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abiotic factor: nonliving environmental factors which affect the ability of organisms to survive

abiotic stress: nonliving environmental factors which can cause stress to organisms, such as soil conditions, drought, extreme temperatures, etc.

abdomen: region of the body furthest from the mouth. In insects, the third body region behind the head and thorax

absorption: one substance taken into the interior of another  See) adsorption & sorption

acellular: not cellular
Examples) prions, viroids and viruses

acid (adj. acidic): water-based solutions that combine with metals or bases to form salts, turn blue litmus paper red and have a sour taste. Acids have a pH lower than 7, strong acids have a pH of 3 or less. Definitions of acids include: Arrhenius - increases the number of free hydrogen ions (H+) in a solution. Brönsted-Lowry - acts as a proton donor in a chemical reaction; Lewis - accepts two electrons to form a covalent bond during a chemical reaction.

acid rain: rain containing nitric acid and sulfuric acid due to presence of sulfur or nitrogen oxides in the atmosphere from burning fossil fuels. Accumulated affects can kill trees and harm aquatic life.

acquired immunity: immunity that develops during a person's lifetime

adaptation: difference that increases an organism's probablity of survival under the conditions of its environment. Types of adaptation are morphological, physiological or reproductive.

adaptive radiation: diversification of a species, driven by the principle mechanism of natural selection, as it adapts to different ecological niches and ultimately evolves into different species through branching evolution; rapid expansion and diversification of an evolving group adapting to new ecological niches; result of different populations becoming reproductively isolated and (usually) adapting to different environments

adenine: a purine (nitrogenous base) and constituent of nucleotides and as such one member of the base pair A-T (adenine-thymine) in DNA and A-U (adenine-uracil) in RNA.

adrenal gland: endocrine gland above each kidney that secretes the adrenaline and noradrenaline (epinephrine and norepinephrine) from its medulla, and steroid hormones from its cortex

adrenal cortex: outer portion of the adrenal gland; that secretes hormones such as hydrocortisone, a glucocortoid, and aldosterone, a mineralocorticoid.

adrenal medulla: inner portion of the adrenal gland that makes epinephrine (adrenaline) in response to low blood levels of glucose as well as exercise and stress; and norepinephrine (noradrenaline) that breaks down stored glycogen into sugar in the liver, facilitates the release of fatty acids from adipose (fat) tissue, dilates small arteries in muscle and increases heart output. Norepinephrine secreted by the adrenal gland acts to narrow blood vessels and raise blood pressure. Underfunction of the adrenal medulla is virtually unknown. However, a tumor called a pheochromocytoma produces norepinephrine and epinephrine and is equivalent to overfunction of the adrenal medulla. Pheochromocytomas arise within the adrenal medulla or elsewhere in the sympathetic nervous system. They typically cause hypertension (high blood pressure) that may be paroxysmal (sharply episodic) with attacks of headaches, feelings of apprehension, sweating, flushing of the face, nausea and vomiting, palpitations and tingling of the extremities (the arms and legs).

adsorption (to adsorb): one material attracting and holding molecules of another substance to the surface of its molecules. A surface effect property of binding to an interface or surface. It is characterised by a surface excess of one species at the interface. The accumulating molecules do not penetrate the substance they are on. Surfactants and polymers are both liable to bind to interfaces. This property may be of crucial importance in imparting colloidal stability to dispersions and in other applications of surfactants such as their use in detergency and as wetting aids.  See) absorption & sorption

aerobic: living or active only in the presence of oxygen; biological process occurring in the presence of molecular oxygen (O2); organisms requiring oxygen for survival.

affect [L. ad + facere to make]: inclination; passion; feeling; disposition; conscious subjective aspect of feeling or emotion; emotional complex associated with an idea or mental state; tend to by affinity or disposition  verb ) have an effect upon; emotional or cognitive impact upon

agar: jellylike material on which bacteria is grown for observation. It is naturally produced by some red algae.

air bladder: tiny grape-shaped structure that acts like an inflatable life-preserver in brown algae

albumin [L. albus=white]: globular protein in many plant and animal tissues that is water-soluble, acid precipitating and heat-coagulating; main protein in human blood and the key to the regulation of the osmotic pressure of blood
Uses) albumin from cow blood is used as an enzyme stabilizer

alga: (Pl. algae): nonvascular unicellular or multicellular eukaryotic nonflowering aquatic plant that lacks true stems, roots, and leaves, but contains chlorophyll and grows in both fresh water and seawater. Algae convert carbon dioxide and inorganic nutrients such as nitrogen and phosphorus into organic matter through photosynthesis and form the basis of the marine food chain.  Taxonomy) {note, classical green algae, Division Chlorophyta} Chrysophyta, Pyrrophyta, Phaeophyta, Rhodophyta, Chlorophyta and Euglenophyta. Uses) Some are used as thickeners or in pigments such as beta carotene or as oxygen producers for aerobic bacteria digesters in sewage treatment. Some cause fouling in pools and reservoirs, or clogging in pipes. Examples) dinoflagellates, diatoms, seaweeds, and kelp.

alkali: strictly speaking, the hydroxide or carbonate salt of an element (one of the unstable alkali and alkaline earth metals) in the first two columns of the periodic table

alkaline: forming or containing an alkali, and by extension, any base

alkalinity: measure of the power of a solution to neutralize hydrogen ions (H+), usually expressed as the equivalent concentration in mg/L of calcium carbonate (CaCO3).

allele: trait specific alleles occupy the same locus or position on homologous chromosomes and thus govern the same trait but because they are different, the resulting expression of that trait may be a different; alternative forms of a gene or genetic characteristic; each member of a gene pair

allergy: reaction that occurs when the body is especially sensitive to certain substances called allergens

alveolus (Pl. alveoli; Latin diminutive of alveus - little cavity or hollow): tiny air sac where the exchange of oxygen and carbon dioxide takes place in the lungs. It is located (like a cell in a honeycomb) in a grapelike cluster at the ends of the bronchioles.

amino acid: any of a class of 20 molecules that combine to form proteins in living things. The sequence of amino acids in a protein and hence protein function are determined by the genetic code.

amniocentesis: process of removing fluid from the sac surrounding a developing baby

amnion: clear membrane that forms a fluid-filled sac around the embryo in the uterus amniotic sac: fluid-f'illed sac that cushions and protects the developing baby in the uterus

amniote: an egg with a hard shell and protective membranes that protect the embryo from drying out.
Examples) reptiles and birds lay amniote eggs

amoeba: unicellular sarcodine [order Amoebida, class Sarcodina], a fresh water protozoan constantly changing in form, that moves and eats with pseudopods

amphiphile [Greek amphi - both + philos - lover]: molecule that has hydrophilic parts with a strong attraction towards both polar solvents and hydrophobic parts attracted to non-polar solvents and will concentrate at the interface between the two

anaerobic: process that occurs with little or no oxygen present

anaerobic respiration: respiration under anaerobic conditions.  Chemistry) the terminal electron acceptor, instead of oxygen in the case of regular respiration, can be: CO2, Fe2+, fumarate, nitrate, nitrite, nitrous oxide, sulphur, sulphate, etc; uses the electron transport chain to dump the electron while fermentation does not

anal pore: structure in a paramecium through which undigested food is eliminated

anaphase: third stage of mitosis during which the chromosomes split apart

anatomy: study of the structure of living things

Angiospermae (flowering plants): major division of the plant kingdom, reproductive organs are in flowers, seeds develop in a closed ovary made of carpels; a very reduced gametophyte, and endosperm develop from a triple fusion nucleus

angiosperm: flowering, fruit-bearing seed plant with ovules covered by a enclosed ovary (protective wall) together known as seeds
See ) Angiospermae

annual ring: one year's growth of xylem cells

anterior: toward the front or in front of

antibiotic: drug or chemical that destroys or weakens disease causing bacteria and is used to treat bacterial infections
Examples) tetracycline (brand names: ACHROMYCIN and SUMYCIN), a broad-spectrum agent effective against a wide variety of bacteria including Hemophilus influenzae, Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia psittaci, Chlamydia trachomatis, Neisseria gonorrhoeae, and many others. The first drug of the tetracycline family, chlortetracycline, was introduced in 1948 History) originally was a substance produced by a microorganism that selectively inhibited the growth of another microorganism. In 1939, after Alexander Fleming discovered penicillin in 1926, Edward Chain and Howard Florey studied penicillin and later carried out human trials of on patients with then fatal bacterial infections. Fleming, Florey and Chain began the era of antibiotics and shared the Nobel Prize in 1945. Today synthetic antibiotics have comparable results.

antibody: protein produced by certain kinds of white blood cells in response to an invasion by a particular organism or substance able to combine with and neutralize antigens (often a virus or bacterium)

antigen: substance that causes an immune system response Examples) a virus or bacterium

antidiuretic: drug that reduces or stops the formation of urine

antigen: invading organism or substance

anti-inflammatory: chemical or drug used in medicine to reduce inflammation

anus: end of the digestive tract, or gut, through which waste products of digestion are excreted, as distinct from the mouth

aorta: largest blood vessel In the body

archaebacteria (Archaea): ancient (over 3.5 billion years old) group of prokaryotic microorganisms in the domain Archaea that are distantly related to eukaryotes and the other prokaryotes. Generally placed within the Kingdom Monera. Some biologists believe this group should be a separate sixth taxonomic Archaea Kingdom.

Archaean [Archean, Gr. archaios=>ancient; fr. arch=>beginning]: beginning eon of Precambrian geologic time (note: Hadean is pre-geologic time) marking the beginning of Geologic history after the earth's suface cooled to form rock and also during which single celled life arose on Earth, as indicated by fossils of bacteria; 3.8 and 2.5 billion years; precedes the Proterozoic eon
Conjecture) The oldest Earth rocks may be older 3.8 billion years old but hard evidence for this is lacking. Erosion and plate tectonics may have destroyed any solid rock older than 3.8 billion years.

artery: large blood vessel that carries oxygenized blood away from the heart; thicker, stronger and more elastic than veins

arthropod: invertebrate having jointed legs a segmented body with an exoskeleton made of chitin

asexual reproduction: reproduction requiring only one parent

asexual budding: asexual reproductive process by which one organism gives rise to a genetically identical organism through growth of a bud that eventually separates from the parent

atherosclerosis: thickening of the inner lining of the arteries

atom: tiny particle of matter with a nucleus containing protons and neutrons and an electron cloud containing electrons

atomic mass units: (dalton, abrev amu) 1/12 of the mass of an atom of the carbon-12 isotope; a unit used for stating atomic and formula weights

atomic weight: weighted average of the masses of the constituent isotopes of an element; the relative masses of atoms of different elements

atrium (plural: atria): upper heart chamber

auto- (aut-) [Gr. autos]: prefix meaning self

autonomic nervous system: controls all involuntary body processes, a part of the peripheral nervous system

autophagosomes: membrane-bound bodies inside cells, which trap and break down organelles

autotroph: organism that can make its own food from simple substances

axil [L. axilla, armpit]: angle between any two organs or structures

axillary: in an axil, growing in an axil
Examples) buds

axon: fiber that carries messages away from a body cell

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bacillus (plural: bacilli) [L. baculus=>rod or stick]: rod-shaped bacterium
Examples) bacteria causing tetanus, diphtheria, pertussis, and tuberculosis; E. coli, Salmonella, Shigella, Klebsiella, Enterobacter, Clostridia; Bacillus Calmett-Guérin is used as vaccination against tuberculosis
History ) the observed shapes, inhabited locations and functions were all early microbiologists had for naming and classification. It was assumed rod-shaped bacteria were closely related, so the genus grouping of "Bacillus" was defined. Different types of bacilli were given species names such as Bacillus coli (found in the gut), and Bacillus typhi (causing Typhoid and now called Salmonella typhi) and Bacillus subtilis (found in rotting hay). The Gram stain showed that many types of bacilli have different cell wall structures. Today the genus Bacillus is still retained for some Gram positive microbes but other bacilli have been moved to genera such as Escherichia, Salmonella, Clostridia, etc. The term bacillus is still retained in some simple alernative names (such as typhoid bacillus) for rod shaped bacteria not in the Bacillus genus, strictly in reference to shape.  See) bacterial shapes

Bacillus anthracis (anthrax, woolsorter's disease): highly contagious and often lethal bacteria causes antrhax disease, afflicts cattle, sheep, horses, mules, and some wild animals and can be transmitted to humans via blood, or other fluids, ingestion of infected raw meat, insect bites, or inhalation; can be used as a biological weapon.
Symptoms) fever, convulsions, lung lesions; cutaneous anthrax (most common form) localized skin lesion with central eschar surrounded by edema (swelling); inhalation (pulmonary) anthrax (woolsorters' disease) hemorrhagic mediastinitis (bleeding into mid-chest), rapidly progressive systemic (bodywide) infection, very high mortality rate; gastrointestinal anthrax rare, high mortality rate.

bacterial shapes: bacteria come in a variety of shapes, the the most common of which are rods (bacilli) and spheres (cocci), others include commas and spirals.

bacteriophage: virus that infects bacteria

bacterium: (Pl. bacteria) unicellular prokaryotic (lacking a nucleus) microorganism that reproduces by cell division and usually has cell walls. It can be shaped like a sphere, a rod or a spiral and is found in every life-supporting environment on earth. Bacteria have an essential role in the recycling of matter. Many bacteria are able to survive, if not proliferate, at low temperatures; however, only some bacteria are able to survive at elevated temperatures. Some bacteria are able to survive high temperatures because they form spores. Once conditions become favorable, the cells return to the vegetative (or actively growing) state.
Size) generally ~1 micrometer (µm) , range 0.1 to >10 µm.   Factoid) Inside your mouth live more bacteria than the number of people who have ever lived. Examples) Clostridium genus, microaerophiles, pathogenic bacteria.  See) archaebacteria, eubacteria

base: water-based solution that reacts with acids to form salts, turns red litmus paper blue, and has a bitter taste and a slippery feel. A base has a pH higher than 7; a strong base will have a pH of 13 or higher. Definitions of bases include: Arrhenius - increases the number of free hydroxide ions (OH-) when added to a solution; Bronsted-Lowry - acts as a proton (H+ acceptor in a chemical reaction; and Lewis - donates electrons to form a covalent bond during a chemical reaction. A base can also be generally referred to a one of four nucleotides that form the building blocks of the nucleic acids, DNA and RNA.

base pair: The two nitrogenous bases held together by weak hydrogen bonds which hold together the two strands of DNA in the shape of the double helix. The number of base pairs (bp) is used as a measure of length of a DNA segment. The two nitrogenous (from purine or pyrimidine) bases (from adenine and thymine or guanine and cytosine) held together by weak hydrogen bonds.

basilar membrane: thin layer of tissue covered with mesothelial cells that separates the cochlea from the scala tympani in the ear

benign: harmless

bile: [L. bilis] substance produced by the liver and secreted into the small intestine where it aids in digestion by breaking down fats for better absorption; yellow, or greenish, viscid fluid, usually alkaline; characteristic constituents are the bile salts, and coloring matters.
History ) ancients considered the bile to be the humor which caused irascibility.

binary fission: reproductive process in which a cell divides into two cells

binomial nomenclature: naming system in which organisms are given two names: a genus and a species

bioaugmentation addition to the environment of bacteria or fungi that can metabolize and grow on specific organic compounds

bio-barrier a biologically active zone that is placed in a subsurface perpendicular to the normal flow of a contaminant plume so that the contaminant can be adsorbed and biologically degraded

bio-chelator a biochemical compound synthesized by living organisms that binds and forms complexes with trace elements and polyvalent cations; use in bio-remediation

biochemistry: scientific study of the chemistry of living cells, tissues, organs and organisms

biogenetic law (alt. recapitulation theory): theory that "ontogeny recapitulates phylogeny," ie, the evolutionary development of a species may be seen by observing the development of an embryo of the species. The theory is not strictly true but is applicable in paleontology.

bioluminescence: glow produced by some fire algae

biome: region with climate, substrates, plants, and animals interacting to produce a large, distinct biotic community

biotechnology: application of technology to the study and solution of problems involving living things

biotic: referring to living things; caused by, or produced by living things; biological aspects of an environment

biotic community: aggregation of different organisms interacting in a common habitat

biotic factor: living things in an environment

biotransformation alteration of the structure of a compound by a living organism or enzyme

bladder: hollow organ in the lower abdomen that is part of the urinary tract which stores urine until it is excreted through the urethra

blood: fluid circulating throughout the body of an animal through blood vessels by the pumping action of the heart, distributing nutrients and oxygen to cells and removing waste from them

blood vessel: tubes that carry blood to and from all parts of the body. The three main types of blood vessels are arteries, veins, and capillaries. The heart pumps blood through these vessels so that the blood can carry with it oxygen and nutrients that the cells need or take away waste that the cells do not need.

botany: study of plants

bovine spongiform encephalopathy (BSE): disease linked to the ingestion of beef infected with prions (the mad-cow disease); speculated that the prions induce changes in the conformation of certain proteins of brain cells

bronchioles: tiny branches of air tubes within the lungs which are the continuation of bronchi and connect to the alveoli (air sacs)

bronchus (plural: bronchi): tube that branches off from the trachea

budding: reproductive process in yeast, in which a new yeast cell is formed from a tiny bud

Bryophyta phylum (mosses): shade-loving, non-vascular spore-producing, non-flowering plants found growing on the ground, on rocks, and on other plants; cannot transport fluids through their bodies so must rely on surrounding moisture; commonly seen as the gametophyte stage while the sporophyte stage is small and overlooked, as opposed to a fern. A few mosses are aquatic and live in bogs or submerged in streams but the majority are terrestrial. Mosses are categorized into three classes: Peat Mosses (Sphagnopsida), Granite Mosses (Andreaopsida), and "True" Mosses (Bryopsida or Musci).
Taxonomy) under Kingdom Plantae   History) the two independent phyla Liverworts (Hepatophyta) and Hornworts (Anthoceraphyta) were at one time considered to be contained by the Bryophyta phylum   Uses) They lay the foundations for other plant growth, prevent erosion, and contribute to the lush green appearance of many forested areas; indicators of the habitat condition since changes in water, soil and/or air quality impact bryophyte growth  See) bryophyte

bryophyte: any primitive plant in the phylum (division) Bryophyta; one of the two types of land plants recogized by plant scientists; life-cycle comprised of two separate generations: the gametophyte generation and the sporophyte generation; the ecologically persistent, photosynthetic phase of the life cycle is the haploid, gametophyte generation; the sporophyte stage is short-lived and the sporophyte remains attached to and nutritionally dependent on the gametophyte. The sporophyte consists of only an unbranched stalk, or seta, and a single, terminal sporangium. Bryophytes do not have a true vascular system and are unable to pull water and nutrients from the ground at significant distance, which distinguishes them as primitive plants, apart from ferns and flowering plants. They never form xylem tissue, the special lignin-containing, water-conducting tissue that is found in the sporophytes of all vascular plants.
alt. ) non-vascular and non-flowering (cryptogam), therefore non-seed producing; includes liverworts, mosses, and hornworts   History) at one time, bryophytes were placed in a single phylum between algae and vascular plants and contained the three classes Hepaticae (liverworts), Anthocerotae (hornworts), and Musci (mosses). Studies of cell ultrastructure and molecular biology now indicate that bryophytes comprise three separate evolutionary lineages, placed into three separate phylums, mosses (phylum Bryophyta), liverworts (phylum Marchantiophyta) and hornworts (phylum Anthocerotophyta); current taxonomic wisdom indicates that the Liverworts and Hornworts are more primitive and only distantly related to Mosses and other plants   Evolution) regarded as transitional between aquatic plants like algae and higher land plants like trees; liverworts are geologically the oldest group, sharing a fossil record with the oldest vascular plants in the Devonian era

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caffeine [Turk. qahveh, Ar. qahuah wine G. Kaffee, Fr. café]: an alkaloid used as a stimulant, metabolized in the liver, the residue of which is excreted through the kidney, half life of caffeine in an adult is about 3 to 4 hours, slower when on oral contraceptives, in pregnancy, up to 18 hours.  Examples) found naturally in coffee beans, tea leaves, cocoa beans (chocolate) and kola nuts (cola)  Uses) added to soft drinks, foods, and medicines  Dosage) 100-200 mg. caffeine can increase alertness, relieve drowsiness and improve thinking. At doses of 250-700 mg/day, caffeine can cause anxiety, insomnia, nervousness and hypertension; a cup of coffee has 100-250 mg; Black tea 40-100 mg; Green tea 15-30 mg  Relevance) can help relieve some headaches, some over-the-counter and prescription pain relievers include it, usually with aspirin or another analgesic; a diuretic which increases urination

calorie: amount of heat energy needed to raise the temperature of I kilogram of water I'C cambium: growth tissue of the stem where xylem and phloem cells are produced

Cambrian { Table }: earliest period of the Paleozoic era, spanning the time between 544 and 505 million years ago.
History) named after Cambria, the Roman name for Wales, where rocks of this age were first studied.

camouflage: hiding from enemies by blending in with the surroundings

cancer: abnormal and uncontrolled cell reproduction

canine: sharp pointed tooth used for tearing and shredding meat

canopy: roof-like formation of branches a forest of tall trees

cap: umbrella-shaped part of a mushroom, which is part of the mushroom's fruiting body

capillary: smallest of blood vessels with walls thin enough for oxygen, glucose and waste products such as carbon dioxide to pass between the capillary and cells.

capsule: cup-shaped part of the nephron in the kidneys

carbohydrate: energy-rich substance found in foods such as vegetables, cereal grains, and breads; compound or molecule that is composed of carbon, oxygen and hydrogen in the ratio of 2H:1C:1O. Carbohydrates can be simple sugars such as sucrose and fructose or complex polysaccharide polymers such as chitin.

carboxyl group: -COOH group; organic molecules containing carboxyl groups are an important, major group of compounds studied in the field of organic chemistry  Chemistry) one of the oxygens is double-bonded to the carbon atom, making it a carbonyl group, and the other oxygen is single bonded to the carbon on one side, and single bonded to the hydrogen on the other. The remaining bond on the carbon atom is attached to the rest of the molecule. .

carcinogen: cancer-causing substance

cardiac muscle: muscle found only in the heart

cardiovascular disease: disease that affects the heart and blood vessels

carnivore: flesh-eating mammal

cartilage: flexible tissue that gives support and shape to body parts

catabolism: breaking down complex substances into simple substances; in biochemistry, the energy-producing breakdown of nutrient molecules.

catalyst: a substance that, through lowering the activation energy of a chemical reaction, promotes the reaction but remains unaltered at the end of the reaction

cell: basic unit, composed of protoplasm, for the structure and function of all living organisms, usually with a nucleus, cytoplasm, and an enclosing membrane; smallest organic unit capable of carrying out all functions normally attributed to life  See) prokaryotic cell, eukaryotic cell.

cell division: process by which two cells are formed from one
See) meiosis, mitosis

cell-free extracts components (eg, enzymes and biochelators) produced in living systems that can be removed and used in bioremedial activities

cell membrane: thin, flexible envelope that surrounds a cell

cellulose: long chain of sugar molecules manufactured by a cell that makes up the cell wall

cell wall: outermost boundary of plant and bacterial cells that is made of cellulose

Celsius: temperature scale used in the metric system in which water freezes at O degrees and boils at 100 degrees

Cenozoic [Gr. new life]: era of geologic time from the end of the Mesozoic era to the present.
Time) 65 million years to the present

central nervous system: part of the nervous system made up of the brain and spinal cord

centriole: structure outside the nucleus in animal cells that plays a part in cell division

centromere: specialized region of chromosome to which spindle fibers attach during mitosis
Exceptions) a few organisms have diffuse centromeres

centrosome: center granular region (containing two centrioles) of microtubule organization during the division of the nucleus

cerebellum: part of the brain that controls balance and posture

cerebrum: part of the brain that controls senses, thought, and conscious activities

chelate a heterocyclic molecule in which a metal ion is bound to at least two nonmetal ions in the same molecule

chelator an agent that causes formation of a chelate

chemical digestion: breaking down of food by enzymes

chemotaxis (chemotactic): movement of cells or organisms toward or away from chemical stimuli

chemotropism orientation response of cells or organisms in relation to chemical stimuli

chitin: polysaccharide molecule in the shell structure of insects, and crustaceans and in the flesh of fungi

chlorophyll: green substance, needed for photosynthesis, found in green plant cells

chloroplast: large, irregularly shaped structure that contains the green pigment chlorophyll; food-making site in green plants

cholera (Vibrio cholerae bacteria, L. vibrio=>to quiver ): devastating and sometimes lethal disease caused by Vibrio cholerae, a comma-shaped bacteria found in the intestines of the infected. Like other Vibrio, Vibrio cholerae moves about actively.
Symptoms) intense vomiting and profuse watery diarrhea leading to dehydration which, unless immediately treated, may be fatal. Thanks to modern sanitary practices, cholera is no longer as common, but remains a global health threat. Epidemics still occur in unsanitary crowded conditions with contaminated water supplies. Treatment) prompt and complete replacement of the fluid and salt lost through the profuse diarrhea. Patients are rehydrated with an oral solution of sugar and salts drunk in large amounts. With prompt and complete oral rehydration, fewer than 1% of cholera patients now die. Very severe cases, especially when oral rehydration is begun late, may require intravenous fluid replacement. Antibiotics shorten the course and diminish the severity, but are not as important as rehydration. Genome) Vibrio cholera was fully sequenced in the year 2000. It is is arranged in two circular chromosomes. The larger has usual "housekeeping" genes, while the smaller contains the pathogenic genetic elements. History) Cholera was discovered in 1883 by German bacteriologist Robert Koch (1843-1910) who studied outbreaks in Egypt and India.

cholesterol: fatty substance found in animal fats, meats, and dairy products

chordate [animal > division > vertebrate]: animals with notochords
Examples) fish, mammals, humans

chromatin: threadlike coils of chromosomes

chromosome: (Gr. chroma=>color; + soma=>body) { Figure } rod-shaped self-replicating genetic structures of cells that direct cell activity and pass traits to new cells. Contains the cellular DNA that bears the linear array of genes in its nucleotide sequence. In prokaryotes, chromosomal DNA is circular, and the entire genome is carried on one chromosome. Eukaryotic genomes consist of a number (usually constant) of chromosomes within the cell nucleus whose DNA is associated with different kinds of proteins. History) term proposed by Waldeyer (1888) for individual deep-staining thread-like bodies inside the cell nucleus.

chromosome theory: theory that states that genes are found on chromosomes and that genes are carried from the parental generation to the next generation on chromosomes

chromatography process of separating gases, liquids, or solids in a mixture or solution by adsorption, as selective adsorption on clay, silica gel, alumina, or paper

chronic disorder: lingering, or lasting, illness

Chrysophyta: division of algae contains 6650 unicellular species, including golden algae, yellow-green algae and diatoms

cilium (Pl. cilia): small, hairlike projection on the outside of a ciliate that acts like a tiny oar for mobility

ciliate: protozoan that moves by means of cilia; one-celled organisms with cilia

circulatory system: body system that delivers food and oxygen to body cells and carries carbon dioxide and other waste products away from body cells

cirrhosis: loss of liver function due to alcohol abuse

clade [Gr klados=>branch or twig]: a monophyletic taxon; a group of organisms which includes the most recent common ancestor of all of its members and all of the descendants of that most recent common ancestor.

cladistics (cladistic analysis): method of phylogenetic analysis for grouping members or hypothesizing relationships among organisms that share a common evolutionary history or shared derived characteristics called synapomorphies and applying three fundamental assumptions: 1. Any group of organisms are related by descent from a common ancestor. 2. There is a bifurcating pattern of cladogenesis. 3. Change in characteristics occurs in lineages over time. We call the original state of the characteristic plesiomorphic and the changed state apomorphic.

class: third classification in the taxonomic sequence, between phylum and order
Examples) Animal: Chordates: Mammalia - animals that breast-feed, which includes humans, cows, dolphins, etc; Animal: Chordates: Reptilia includes cold-blooded, scaled animals

classification: grouping of living things according to similar characteristics

climate: average weather in a particular place over a long period of'time

Clostridium genus containing nearly 100 species of bacteria, all obligately anaerobic, gram-positive, sporeforming bacilli. Most species are harmless, and some are even industrially useful. Clostridium tetani and C. perfringens produce powerful toxins. The tetanus toxin is 20 times stronger than cobra venom and 150 times stronger than strychnine. These bacteria are found in both soil and feces. They do not grow on healthy, living tissue; however, they can multiply rapidly after entering deep cuts or puncture wounds.

club fungus: fungus that produces spores in a club-shaped structure

Coccidiosis: disease caused by microscopic, single-cell organisms called coccidia. It can be treated with drugs known as coccidiostats

coccus (Pl. cocci) [Gr. kokkus=>grain or berry] { Figure }: spherically shaped bacterium
See) bacterial shapes

coelenterate: phylum of inverte-brates that contain a central cavity with only one opening

cochlea: spiraling tube in the inner ear from which nerve impulses are carried to the brain; part of the internal ear concerned with hearing.

coldblooded: having a body temperature that can change somewhat with changes in the temperature of the environment

coldwater fish: prefer water temperature ranges between 7-18 ºC (45-65 ºF) Examples) trout and salmon  See) coolwater- and warmwater fish)

coliform: group of bacteria which live within the bowels of larger organisms that ferment lactose and produce carbon dioxide gas; generally small, gram-negative, nonsporing, bacilliform (shaped like rods), facultative anaerobes; utilized as indicator organisms for the potential presence of enteric pathogens in water; found in sewage
Examples) Escherichia, Kelbsiella, Enterobacter, and Citrobacter

colloid (colloidal): microscopic dispersion of any gas, solid, or liquid particles in a fine state of subdivision that are suspended in a continuous fluid or solid medium and are not readily filtered and do not settle out or settle very slowly.

colloidal dispersion: mixture containing particles larger than those found in a solution but small enough to remain suspended for a very long time.

colorblindness: sex-linked trait that causes the inability to distinguish between certain colors

commensalism: (commensal) symbiotic relationship between populations of organisms in which only one partner benefits without damaging or benefiting the the other(s).

communicable disease: disease transmitted among people by harmful or-ganisms such as viruses and bacteria; infectious disease

community: living part of any ecosystem

competition: struggle among living things to get the proper amount of food, water, and energy compound: two or more elements chemically combined

compound light microscope: microscope having more than one lens and that uses a beam of light to magnify objects

conductivity: measure of the ability of an aqueous solution to transmit electrical current, or the inverse of electrical resistance

coniferous forest: northernmost forest biome, which contains conifers, or cone-bearing trees

conjugation: type of sexual reproduction in which hereditary material is exchanged

connective tissue: type of tissue that provides support for the body and unites its parts

conservation: wise use of natural resources so that they will not be used up too soon or used in a way that will damage the environment

consumer: organism that feeds directly or indirectly on producers

contour farming: farming method in which a slope is plowed horizontally across its face to avoid erosion

contour feather: large feather used for flight that is found on a bird's wing and on most of the bird's body

contractile vacuole: structure in protozoans through which excess water is pumped out

control: experiment done in exactly the same way as another experiment, but without the variable

coolwater fish: prefer a temperature range between that of coldwater and warmwater fish. Examples) striped bass, northern pike, and walleye.

cornea: transparent protective covering of the eye

cotyledon: leaflike structure of a young plant that stores food

covariates: explanatory variables that could affect the variables being measured or studied

crop: saclike organ that stores food in an earthworm

crop rotation: farming method of alternating the growth of different crops each year on the same land

cross-pollination: process in which pollen is transferred from the male part of one flower to the female part of another flower

crustacean: [phylum Arthropoda (arthropods): class Crustacea] majority of these animals are marine; the rest are aquatic
Examples) crab, lobster, shrimp, barnacle, water flea, crayfish

cryptogam: plant that produces spores, not seeds, in its sexual reproductive cycle; plant whose sexual reproductive parts are inconspicuous
Examples) ferns, mosses, algae   See) phanerogam

Cryptosporidium: the only waterborne coccidian parasite known to infect humans; the cause of enterocolitis and diarrhea in several species, including humans. Drinking water contaminated with Cryptosporidium oocysts has been blamed in a number of gastroenteritis outbreaks.
Symptoms) severe gastrointestinal infection and eventual death in immunocompromised individuals; rarely serious in healthy persons and typically characterized by a self-limiting diarrhea.  Causes) potentially pets and farm animals, contaminated foods and contaminated waters, association with infected persons.  History) First observed in laboratory mice early in this century, it was considered a rare, largely asymptomatic infection and was ignored for 60 years; first cases in humans reported 1976, increased awareness and its association with HIV-infected individuals came 80's

cutaneous: relating to the skin

cuticle: waxy covering of the epidermis that prevents the loss of too much water from a leaf

cyanobacteria: (alt. misnomer: blue-green algae) photosynthetic aquatic bacteria (not algae), usually unicellular, but often growing in macroscopic colonies, and formed the oldest known fossils (>3.5 billion years). Many Proterozoic oil deposits are attributed to their activity, providers of nitrogen fertilizer in the cultivation of rice and beans, responsible for having generating the oxygen atmosphere in the Archaean and Proterozoic Eras and contributed to the origin of plants in the late Proterozoic or early Cambrian Era. Through endosymbiosis, cyanobacteria took residence within certain eukaryote cells, making food for the eukaryote and developing into a chloroplast, marking the origin of the eukaryotic mitochondrion. etymology) called "blue-green algae" because they are photosynthetic and aquatic, but are relatives of bacteria, not eukaryotic algae. It is only the chloroplast in eukaryotic algae to which the cyanobacteria are related.

cyst: (can refer a structure or a dormant stage) dormant form of some bacteria, reproductive bodies and embryos.  Examples of bacteria) Cryptosporidium, Giardia, Toxoplasma and Entamoeba.  alt.) closed sac or pouch which generally contains semisolids, fluids, or gases, parasites, or other non-pus materials that may be a normal or abnormal part of the body.

cytochrome any of several respiratory pigments that occur in animal and plant cells which play a major role in intracellular oxidations, and are related chemically to hemoglobin

cytoplasm [Latin plasmator: maker, plasmo: to mould] excluding the nucleus, all of the protoplasm (living material) within a cell, consisting of a semifluid material and contains numerous functional structures (organelles)

cytosine: a pyrimidine (nitrogenous base) and constituent of nucleotides and as such one member of the base pair G-C (guanine and cytosine).

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data: recorded observations and measurements

deciduous forest: forest biome that contains deciduous trees, which shed their leaves in the autumn

decomposer: organism that feeds on dead organic matter and breaks it down into simpler substances

dendrite: fiber that carries messages from a neuron toward the cell body

denitrification: reduction of nitrate-yielding gaseous nitrogen

density: measure of how much mass is contained in volume of an object

depletion: process in which nutrients are washed away from the soil by water

depressant: drug that slows down the actions of the nervous system

derived character state (derived characteristics): a character state that is present in one or more subclades (but not all such subclads) of the clade under consideration; inferred to be a modified version of the primitive condition of that character, and to have arisen later in the evolution of the clade.
Examples) presence of hair is a primitive character state for all mammals, whereas the hairlessness of whales is a derived state for one subclade within Mammalia

dermis: inner layer of the skin

desert: biome that receives less than 25 centimeters (10 inches) of rainfall a year

detritus: fresh or partly decomposed dead organic matter

detritovore: organism that feeds on detritus (usually a detritus feeder other than bacteria and fungi).

Devonian : period of the Paleozoic era, spanning the time between 410 and 360 million years ago.
History) It is named after Devonshire, England, where rocks of this age were first studied   See) geologic time

diabetes mellitus (sugar diabetes): disease preventing the utilization of blood glucose (metabolized carbohydrates) for energy due to low or ineffective insulin (hormone) needed for glucose to be absorbed and utilized by tissues.  Causes) pancreas is not able to make enough insulin or available insulin is ineffective  Symptoms) the bloodstream and kidneys try to flush out resulting high levels of unused glucose, hence increased frequency of urination excessive and excessive thirst or hunger, weight loss, loss of energy; blurred vision, itching, slow healing; after a long period capillaries may become weakened, especially in the kidney and the retina of the eye.  Causes) unknown; type I (insulin-dependent) diabetes may be more than one disease possibly caused by genetic factors and viruses

diaphragm: muscle at the bottom of the chest that aids in breathing

diatom: [Bacillariophyceae class), Chrysophytatype division, Algae] motile organisms with a characteristic thin siliceous shell ie, cell wall similar to a green house and have no flagella. The chloroplasts are yellow-brown instead of the green common to other photosynthetic organisms. Many are non-motile, most occur as plankton, found in fresh and salt water,  Taxonomy) patterns in the shells are used to identify species. There are two different groups of diatoms, the pennates which are pen shaped and the centric which are like a cylinder. In fresh water most diatoms are pennate.

diffuse centromeres: having centromeric properties distributed over the entire length of the chromosome
See) centromere

diffusion: process by which food molecules, oxygen, water, and other materials enter and leave a cell through the cell membrane

digest: break down

digestion: process by which food is broken down into simpler substances

digestive system: body system in which food is broken down into simpler substances for use by the body

dinoflagellate [Pyrrophyta division, Algae]: most are unicellular biflagellate (has two flagella) with thick armor-like cellulose plates and most occur as plankton, found in fresh and salt water, can secrete toxins leading to occurrence of "red tides" during which many aquatic organisms, especially those in the benthos, may perish. Species) > 1000

dioecious: having separate sexes; eggs and sperm produced by separate individuals

diploid cell: cell containing a nucleus with two complete sets of chromosomes, one set inherited from each parent. The diploid condition is often abbreviated as 2n
See) haploid

diploid number: the full component of chromosomes normally found in somatic cells  See) haploid number

disaccharide: a sugar composed from one glucose molecule and one fructose molecule, both of which are monosaccharides
Examples) sucrose

dispersion: two substances mixed together such that one is not dissolved in the other. For example, milk, a dispersion of globules of fat in water; latex paint, a dispersion of polymer particles in water; smoke, a dispersion of carbon particles in air.

dissolved oxygen: below 3 parts per millinon is generally stressful to aquatic organisms

diuretic [Gr. "dia-", thoroughly + "ourein", to urinate; L. diureticus]: drug or substance in food or drink (such as coffee, tea, and alcoholic beverages) that promote the formation of urine by the kidney  Uses) treating hypertension  Examples) diuretic drugs: Aldactone (spironolactone), Dyazide (triamterene), Hydrodiuril (hydrochlorothiazide), Lasix (furosemide), and Maxzide (triamterene).

division of labor: division of the work among the different parts of an organism's body that keeps an organism alive

DNA (deoxyribonticleic acid): nucleic acid molecule that stores the genetic information about an organism and the information needed to build proteins. DNA is a double-stranded molecule held together by weak bonds between base pairs of nucleotides. DNA nucleotides) adenine (A), guanine (G), cytosine (C), and thymine (T). In nature, base pairs form only between A <=> T and G <=> C;. Thus, the base sequence of each strand can be deduced from the other.  See) RNA)

dominant: stronger trait in genetics

dysentery: (Greek dys=>abnormal or painful + enteron=>intestine) an often painful intestinal inflammation (especially of the colon) usually caused by amebic infestation of the bowel, which can be fatal (usually due to dehydration); There are two specific varieties: (1) amebic dysentery (2) bacillary dysentery.  Symptoms) diarrhea, bloody stools..  Treatment) rapid rehydration and medication.

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effect [L. ex + facere to make]: consequence, result; produced by an agent or cause  See) affect

Escherichia coli: (E. coli) common colon bacillus type of bacterium; most strains are harmless, but others can cause waterborne or foodborne illness; studied intensively by geneticists because of its has a small genome, is easy to grow and is usually harmless.
Examples) E. coli 0157:H7 is a major health problem and produces toxins that can damage the lining of the intestine; causes hemorrhagic diarrhea (bloody colitis)  Symptoms) bloody diarrhea with gross blood in the stool, painful abdominal cramps, lasting a week; occasionally kidney failure  Causes) eating undercooked, contaminated ground beef, drinking raw milk, swimming in or drinking sewage-contaminated water  Transmission) person-to-person contact in families and child care centers  Prevention) thoroughly cook ground beef, avoid unpasteurized milk, wash hands carefully

ecotoxicity quality, state, or relative degree of being toxic or poisonous to the environment and the ecological system

ectoplasm: cytoplasm embedded with microfilaments (to give it rigidity) and lacking organelles that is found just under the cytoplasmic membrane in ciliates.

Eh standard oxidation reduction potential (redox potential); energy gained in the transfer of 1 mol of electrons from an oxidant to H2

emulsion: colloidal dispersion of one liquid in another liquid (usually an oil and water). It is often stabilised with a surfactant or with polymers. Emulsions are not usually truly stable but may be metastable. This is in contrast to microemulsions.

encephalitis: inflammation of the brain which can cause brain damage or may result in or exacerbate symptoms of developmental disorder or mental illness; usually runs a short course with full recovery within a week; eventuates in central nervous system impairment or death in some cases; treatment begins early to avoid serious, life-long effects.
Causes) after (up to 3 weeks) onset of (1 in 1,000 cases) the measles rash, with high fever, convulsions, and coma  Treatment) antibiotics, anti-viral medications, and anti-imflammatory drugs; if brain damage results, physical therapy or cognitive restoration therapy may help to regain lost functions

encephalitis lethargica (sleeping sickness): results in a set of Parkinson’s disease-like symptoms called postencephalitic parkinsonianism


endocrine gland: gland that secretes directly into the bloodstream.  See) exocrine gland.

endogenous: growing from or on the inside; developing within the cell wall; arising from internal structural or functional causes; constituting or relating to metabolism of the nitrogenous constituents of cells or tissues.

endoplasm: portion of the cytoplasm of a cell closest to the nucleus; inner portion of the cytoplasm or protoplasm in the interior of a cell

endosperm (albumen): nutritive tissue in a seed; in an angiosperm it is triploid and formed in the embryo sac after fertilization; in a gymnosperm, it is haploid and is derived from the sterile portion of the female gametophyte.
See) perisperm

endotoxins: produced within cells, but they are either part of the cell walls or the cytoplasm; therefore, they are not released until the cells die and lyse (break apart and disintegrate).  See) exotoxin

enzymes: proteins that act as catalysts, speeding the rate at which biochemical reactions proceed but not altering the direction or nature of the reactions.

epidemiology: the study of the factors that cause disease and of the factors that influence distribution of disease within a population


epinephrine (adrenaline): hormone produced and secreted by the adrenal gland in response to low glucose in the blood and to exercise and stress which acts as a stimulant to increase blood pressure, heart rate, and other functions; it causes the breakdown of the stored glycogen into glucose in the liver, dilation of the small arteries within muscle and increases heart rate (output), (facilitates) release of fatty acids from adipose (fat) tissue; also acts as as a neurotransmitter which transmits nerve signals from neuron to neuron.
Chemistry) C9H13NO3.

epistaxis: profuse bleeding from the nose

epithelium: cells joined by small amounts of cementing substances which cover internal and external surfaces of the body.

esophagus: pipe-shaped tube that transports food to the stomach

estrogen: hormone that triggers the broadening of the hlps in females and starts the maturation of egg cells in the ovaries

eukaryote: (eucaryote, eukaryotic, eucaryotic cell) cell or organism that maintains the genome within a membrane-bound, structurally discrete nucleus and has many functions segregated into well-developed semi-autonomous subcellular compartments (organelles), and by the cytoskeleton. Eukaryotes include all organisms except viruses, bacteria, and cyanobacteria (blue-green algae). Examples) humans and other animals, plants, fungi and protists.  Taxonomy) the Eukaryotes, Archaea and Eubacteria make up the three major branches of living organisms (viruses excepted).  See) prokaryote

eukaryotic cell: cell structure of eukaryotes, which divides by mitosis and has a true nucleus.  See) prokaryotic cell

eutrophication: enrichment of a body of water with nutrients, resulting in excessive growth of microbes, deoxygenation, and a deterioration of the water quality with respect to human use

evaporation: process in which radiant heat gain or loss of pressure turns liquid water into a gas

evolution: change in a species over time

excrete: separate, throw off or get rid of waste material

excretory system: body system that removes body wastes

exhale: breathe out

exocrine gland: releases chemicals into a nearby organ through a duct or tube

exoskeleton: rigid, outer covering of an organism

exotoxins: harmful (toxic) substances, produced within cells, that are then released  See) endotoxin

expression system: system in which a cloned gene can be expressed. Elements used to evaluate the quality of an expression system include the number of copies of the gene per cell, the strength of the transcriptional promoter, the presence of the bacterial ribosome binding site, codon usage, and the fate of the protein.

ex situ in a position or location other than the natural or original one

external fertilization: fertilization that occurs outside the body of the female

extinct: having died out

extinction: process by which a species passes out of existence

extremophiles group of organisms whose growth is dependent on extreme environmental conditions, Examples) extreme halophiles, psychrophiles (cold), or thermophiles (heat)

eyespot: reddish structure in Euglena that is sensitive to light

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facultative: capable of functioning under varying environmental conditions, such as bacteria that can live with or without oxygen.

facultative anaerobes: bacteria which can survive with or without oxygen Examples) Escherichia coli.

Fallopian tube: oviduct; tube through which an egg travels from the ovary

family: fifth classification in the taxonomic sequence, between order and genus and withn which most organisms have the same behavior patterns, feeding habits, and general functions
Examples) Cat Family (Felidaes) which all have whiskers, sharp claws, and include animals such as Lions and Cats

fang: special tooth in snakes used to inject venom into their prey

fat: substance that supplies the body with energy and helps support and cushion the vital organs in the body

fecal coliform: subset of the total coliform group of bacteria generally considered to be a more reliable indicator of human or animal fecal pollution than the total coliform group, although there are certain limitations to their utility as an indicator. Fecal coliform is a portion of the coliform bacteria group originating in the intestinal tract of warm-blooded animals that pass into the environment as feces. Fecal coliform often is used as an indicator of the bacteriological safety of a domestic water supply. The fecal coliform bacterial densities will be determined using the membrane filtration technique. The MF procedure uses an enriched lactose medium and an incubation temperature of 44.5 + 0.2oC. Fecal coliform is bacteria typically found in the feces of warm blooded mammals. Fecal coliform colonies produced by the M-FC medium are blue, while non-coliform colonies are pale yellow, gray, or cream color. Since fecal coliform is found in mammalian waste, it is recommended that fecal coliform be absent from potable water. Bacteria from the colons of warm-blooded animals which are released in fecal material. Specifically, this group comprises all of the aerobic and facultative anaerobic, gram-negative, non-spore-forming, rod-shaped bacteria that ferment lactose with gas formation within 48 hours at 35 degrees Celsius.

feces: solid waste that is eliminated from the body

feedback inhibition mechanism by which the end product of the cell's biosynthetic pathway inhibits the activity of the first enzymes in the same pathway. This mechanism controls enzymatic activity so that resources can be conserved and regulated.

feedback mechanism: process In the endocrine system in which the production of a hormone is controlled by the concentration of another hormone

fermentation: energy-releasing chemical decomposition process, an oxygen-free environment, in which a substance, usually a carbohydrate is changed into alcohol and carbon dioxide due to the action of enzymes produced by bacteria, yeasts or molds; typically the conversion of starch or sugar into ethyl alcohol

ferns (Pterophyta, Pteridophyte): vascular plants under the Plantae Kingdom that reproduce from spores rather than seeds and have true leaves, roots and stems; commonly seen as the sporophyte stage while the gametophyte stage is small and overlooked, as opposed to a moss. Leaves are macrophylls and, in many families, demonstrate circinate vernation (a pattern of uncoiling of a crozier-like structure due to uneven growth). While arborescent species exist, no living fern demonstrates true secondary growth. Roots are adventitious.  Reproduction) either homosporous and exosporic or heterosporous and endosporic. Homospory with the production of photosythetic free-living gametophytes is the most common pattern. Alternation of generations between a dominant vascular sporophyte initially dependent upon the very reduced gametophyte Taxonomy) spore, sporangium and sorus structure are important taxonomic features  Paleontology) fossils dating back to the lower Devonian

fertilization: joining of the egg and the sperm

fetus: developing baby from the eighth week until birth

fibrin: substance that traps blood cells and plasma, forming a scab

flagellate: protozoan that moves by means of flagella

flagellum (Pl. flagella): long, thin whiplike appendage which can be the organ of locomotion of a motile cell Examples) whiplash, with a smooth continuous surface, and tinsel, with the surface covered with mastigonemes (hair-like processes).

flower: structure containing the reproductive organs of an angiosperm

food chain: food and energy links between the different plants and animals in an ecosystem

food vacuole: spherical structure in protozoans that digests food particles

food web: all the food chains in an ecosystem that are connected

formula: combination of chemical symbols that shows the elements that make up a compound and the number of atoms of each element in a molecule of that compound

fossils: imprint or remains of plants or animals that existed in the past; recognizable remains, such as bones, shells, or leaves, or other evidence, such as tracks, burrows, or impressions, of past life on Earth.

fossil fuel: product of decayed plants and animals that is preserved in the earth's crust over millions of years

fossil record: most complete biological record of life on earth

freshwater biome: biome that contains freshwater lakes, poiids, swamps, streams, and rivers

frond: leaf of a fern plant

fructose (fructopyranose) [=>fruit sugar]: six-carbon (monosacharide) sugar which is a bulding block for more complex sugars and carbohydrates

frugivore: animal that primarily eats fruit
Examples) many bats and birds

fruit: ripened ovary of an angiosperm

fruiting body: spore-containing structure in a fungus

fungus (Pl. fungi): nonvascular, plant-like organism that contains no chlorophyll; ability to export hydrolytic enzymes (as do animals) that break down biopolymers absorbed for nutrition. Rather than requiring a stomach for digestion, fungi live in their food supply and grow into new food as the local environment becomes depleted. When a filament contacts nutrients, the entire colony mobilizes and reallocates resources. Should all food become depleted, sporulation is triggered. Although the fungal filaments and spores are microscopic, the colony can be very large with individuals of some species rivaling the mass of the largest plants and animals.  Taxonomy) sister group of animals and part of the eukaryotic crown group that radiated (~1 billion years ago), constitute an independent group equal in rank to that of plants and animals. Examples) mushrooms, rusts, smuts, puffballs, truffles, morels, molds, and yeasts. Species) >70,000 described; <=1.5 million total estimated

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gall bladder: organ that stores bile gene: basic unit of heredity

gametes: reproductive cells (in animals, sperm produced in the testes or unfertilized ovum cells , ie. eggs in ovaries, produced by meiosis and normally having half the number of chromosomes found in somatic cells.

gametophyte (gametophytic): plant, or phase of a plant's life cycle, that bears gametes
See) sporophyte  Examples) ferns, mosses

gametophyte stage: stage in which a plant is able to re-produce sexually (similar to flowering plants) with sexual parts contained in small and inconspicuous structures (usually unlike flowers). Antheridia (the male organs) produce mobile antherozoids requiring a film of water to move to the archegonia (female organs). After fertilisation, a new plant develops, which remains attached to, and appearing to be part, of the parent plant. This is the sporophyte. Another common means of gametophyte reproduction is through shedding fragments of leaves or other parts that can regenerate into new plants. In some species, specialised groups of cells known as gemmae are produced for this purpose.

gene fundamental unit of heredity, an ordered sequence of nucleotides located in a particular position on a particular chromosome that encodes a specific functional molecule or unit within an organism; a section of DNA coding for a single polypeptide chain, a particular species of transfer RNA or ribosomal RNA, or a sequence that is recognized by and interacts with regulatory proteins.

generalist: organism that is not specialized to live under particular ecological circumstances and can survive under a wide variety of conditions

genetic code: the sequence of nucleotides, coded in triplets (codons) along the mRNA, that determines the sequence of amino acids in protein synthesis. The DNA sequence of a gene can be used to predict this mRNA sequence, and the genetic code can in turn be used to predict the amino acid sequence.

genetic engineering: process in which single genes (or parts of DNA) are isolated, studied, and transferred into cells of the same or different species

genetics: (Gr. genesis, descent) The study of heredity or of the patterns of inheritance of specific traits. History) term coined by Bateson (1907) for the science of heredity and variation.

genome: all genetic material in the chromosomes of an organism, the size of which is generally given as its total number of base pairs (bp); the sum of all chromosomal genes in a haploid cell (including prokaryotes), or the haploid set of chromosomes in a eukaryotic cell

genotype: the type species of a genus; the genetic constitution, makeup or totality of genes of an individual or group

genus (plural: genera): sixth classification in the taxonomic sequence, between family and species and the first word of the binomial nomenclature of an organism; interbreeding between organisms within the same genus and different species may occur

geologic time: period of time extending from the formation of the earth to the present
See) Precambrian; EONS: Hadean, Archaean, Proterozoic, Phanerozoic; ERAS: Paleozoic, Mesozoic, Cenozoic; PERIODS: Cambrian , Ordovician, Silurian, Devonian, Carboniferous (Mississippian, Pennsylvanian), Permian, Triassic, Jurassic, Cretaceous, Tertiary (Paleogene, Neogene), Quaternary

geologic time scale { Table }: arbitrary chronologic sequence of geologic events, used as a measure of the age of any part of geologic time, usually presented in the form of a chart showing the names of the various rock-stratigraphic, time-stratigraphic, or geologic-time units.

geothermal energy: energy that comes from heat created in the earth

germination: early growth stage, or the "sprouting," of a young plant

germ plasm:liquid portion of a gamete that contains genetic material

Gertsmann-Straeussler-Scheinker disease: unusual form of hereditary dementia

gill: spore-producing structure in a mushroom; structure through which water-dwelling animals obtain oxygen

gizzard: structure in an earthworm that grinds up food

gland: structures or organs, in a living organism, with specialized cells that secrete or excrete a liquid chemical that may have various purposes.

globular proteins: water-soluble, roughly spherical proteins

glucagon: raises the level of glucose in the blood

glucocortoid: chemical that helps cells to synthesize glucose, catabolize proteins, mobilize free fatty acids, and inhibit inflammation in allergic responses

glucose (dextrose): major sugar in the blood utilized for energy; an intermediate molecule in metabolic processes  Uses) often given intravenously to replenish fluids and nutrients  Chemistry) six-carbon monosaccharide, C6H12O6

glycogen: polysaccharide used for energy storage made up of chains of glucose molecules; the liver breaks down glycogen into glucose when the blood is depleted of free glucose  Chemistry) C24H42O21

glycolysis: sequence of reactions that converts glucose into pyruvate with the concomitant production of a relatively small amount of ATP. Glycolysis can be carried out anerobically (in the absence of oxygen), especially to organisms that ferment sugars.  Examples) utilized by yeast to produce the alcohol  Uses) source of raw materials for the synthesis of chemical compounds. For example, 3 phosphoglycerate can be converted into serine.

golden algae (Chrysophyceae class) {Chrysophytatype Division {Algae: most are flagellated, found in fresh and salt water, > 500 species

gradualism: belief that evolution is a slow and steady process

Gram, J.M.C.: (1853-1938) Danish bacteriologist that devised a 4-step method to distinguish between bacteria using crystal (gentian) violet dye. (1) apply a primary stain (crystal violet), (2) apply an iodine solution (acts as a mordant: it causes the primary stain to adhere to the cells better), (3) rinse with 95% ethyl alcohol (decolorizer), then (4) apply a counterstain (can use eosin Y, safranin O, brilliant green, or Bismarck brown).  See) Gram-positive, Gram-negative)

gram molecular weight: weight in grams numerically equal to the molecular weight of a substance

Gram-negative: bacteria that lose the crystal violet Gram stain (and take the color of the red counterstain) due to a cell wall composed of a relatively thin layer of a peptidoglycan. Examples) most of the bacteria normally found in the gastrointestinal tract that can be responsible for disease as well as gonococci (veneral disease) and meningococci (bacterial meningitis). The organisms responsible for cholera and bubonic plague are Gram-negative.

Gram-positive: bacteria that retain the color of the crystal violet Gram stain due to a cell wall composed of a relatively thick layer of peptidologlycan. Examples) staphylococci ("staph"), streptococci ("strep"), pneumococci, and the bacterium responsible for diphtheria (Cornynebacterium diphtheriae) and anthrax (Bacillus anthracis)

granulocytes (polymorphonuclear leukocytes): leukocytes containing the enzyme myeloperoxidase and characterized by granules in their cytoplasm; active in allergic immune reactions such as arthritic inflammation and rashes; classified according to the pattern and color exhibited when stained
Examples) basophils, eosinophils, neutrophils

grassland: biome made up mainly of grasses that receive between 25 and 75 centimeters (10 and 30 inches) of rainfall yearly

green plants: Taxonomy) green plants, subkingdom Chlorobionta, have two major lineages: 1) most of what have been classically considered "green algae"--microscopic freshwater forms and large seaweeds (Prasinophytes, Chlorophyceae, Trebouxiophyceae, and Ulvophyceae); 2) Streptophytes several groups of traditional "green algae" more closely related to land plants (embryophytes), including the traditional Class Charophyceae (some members, particularly Order Charales, and Coleochaetales are more closely related to higher plants than to co-members), plus the familiar green plants found mostly on land. Ultrastructural and morphological studies were the first to support the relationship of these orders of green algae to land plants (Pickett-Heaps, 1975; Mishler and Churchill, 1985; Graham et al., 1991). The orders were all placed in the class Charophyceae (Mattox and Stewart, 1984) and retained within the green algae (Division Chlorophyta in the classical sense [Bold and Wynne, 1985]. Recent analyses suggest that the Charophyceae is a paraphyletic group, and therefore the orders originally circumscribed within it have been placed within the Streptophyta (Bremer, 1985). Later molecular studies (reviews in McCourt, 1995 and Melkonian and Surek, 1995) largely confirmed this close relationship, and confirmed what the ultrastructural and morphological data had first suggested: that the Charophyceae is a paraphyletic assemblage. Specifically, the Charales and Coleochaetales are most closely related to land plants (Chapman and Buchheim, 1991; Ragan et al. 1993; Surek et al., 1993; Bhattacharya et al., 1994). The Charales/Coleochaetales/Embryophyte clade is shown as unresolved because morphological and molecular studies to date have not fully resolved which of the green algae is the sister taxon of land plants (McCourt 1995; Melkonian and Surek, 1995).

gravity: force of attraction between objects

groundwater: underground water

guanine: a purine (nitrogenous base) and constituent of nucleotides and as such one member of the base pair G-C (guanine and cytosine).

guard cell: satisage-shaped cell that regulates the opening and closing of stomata

gullet: funnel-shaped structure in a paramecium through which food passes from the oral groove to the food vacuole

gymnosperm:: type of seed plant whose seeds are not covered by a protective wall; seed plant with the ovules borne on the surface of a sporophyll
See) angiosperm

Gymnospermae: division of the plant kingdom, being woody plants with alternation of generations, having the gametophyte retained on the sporophyte and seeds produced on the surface of the sporophylls and not enclosed in an ovary

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habitat: place in which an organism lives

Hadean Eon: period predating geologic time spanning between the formation of the Earth (~4.5 billion years) and the Archaean eon; earliest subdivision of the Precambrian time. No rocks of this age are known on Earth, with the exception of a few meteorites. During Hadean time, the Solar System was forming, probably within a large cloud of gas and dust around the sun called an accretion disc. The Earth and other planets would have been molten at the beginning of their histories. The oldest meteorites and lunar rocks are ~4.5 billion years old. During the first ~800 million years of its history, the surface of the Earth cooled, changing from liquid to solid and forming rocks.

hair cells: mechanoreceptors located in the organ of corti that are sensitive to auditory stimuli and in the vestibular apparatus that are sensitive to movement of the head. Appropriate stimuli cause movement of the hair-like projections (stereocilia and kinocilia) which relay the information centrally in the nervous system.

half-life: time it takes for half of a radioactive element to decay; time required for half of a substance introduced to a living system or ecosystem to be eliminated or disintegrated by natural processes.

hallucinogen (huh-Loo-suh-nuh-jehn): drug that produces powerful hallucinations

haploid: single set of chromosomes (half the full set) present in the egg and sperm cells of animals and in the egg and pollen cells of plants

haploid number: the number of chromosomes in gametes as a result of the halving of chromosome pairs in meiosis.  See) diploid number

Haversian canal: passageway running through the thick bone, containing blood vessels and nerves

hazardous waste: waste that is poisonous, or reacts dangerously with other substances

heavy metals metals of high specific gravity (5.0 or higher)

hemoglobin: oxygen-carrying protein in red blood cells of vertebrates and some invertebrates

hemophilia: inherited disease that causes the blood to clot slowly or not at all

herbaceous stem: soft, green plant stem

herbivore: organism that eats only plants

heredity: organic relation between successive generations; passing a particular trait or characteristic from forebear to progeny; biological similarity of progeny and parents; sum of an organism's inherited genetic traits.

heterocyst one of three types of specialized cells that form in filamentous cyanobacteria in response to environmental conditions, involved in the fixation of atmospheric nitrogen

heterotroph: organism unable to make its own food, hence obtains chemical energy preformed organic molecules

hibernation: winter sleep during which all body activities slow down

hilum: scar on a seed coat at the place where it was attached to its stalk during development

histological: pertaining to the microscopic structure of plant and animal tissues

holdfast: rootlike structure that attaches an alga to a rock or other object on the ocean floor

homeostasis: relatively stable state of equilibrium between different but interdependent elements or groups of elements of an organism, population, or group; ability of an organism to keep conditions inside its body the same even though conditions in its external environment change.

homologous: similar in structure

homologous chromosomes: are paired during meiosis and have the same genes (but not necessarily the same alleles) at the same location, alike in size and position of the centromere.

hormone: biochemical substance acting as a messenger in an organism, which is produced by a cell or tissue and causes a change or activity in another cell or tissue; harmones may be transported by the blood

host: organism in which another organism lives

hybrid: organism produced through hybridization; organism with two different genes for a particular trait

hybridization: crossing of two genetically different but related species of an organism

hybrid vigor: ability of hybrids to grow faster or larger than their parents

hydrophilic: a substance that attracts, dissolves in, or absorbs water; a molecule or a part of a molecule that is attracted to water or an aqueous phase.

hydrophobic: having a strong aversion to water; substance that is is attracted to non-polar solvents and repels, will not absorb, or is insoluble in water or other polar fluids; molecule or a part of a molecule that is adverse to being in contact with water or an aqueous phase; organism that is harmed by water or a wet environment hydrophobic bonding: attraction of hydrophobic and nonpolar molecules (parts of molecules) to each other in the presence of water or other polar fluids. Hydrophobic molecules will form clumps so that the interiors are away from water.

hydrophobic interaction: attractive force between molecules due to the close positioning of non-hydrophilic portions of the two molecules.

hydroplasma: liquid portions of protoplasm or all of the liquid contained within a live cell.

hyperplasia abnormal increase in tissue growth caused by excessive cell division  See) hypertrophy)

hypertension: high blood pressure

hypertrophy excessive enlargement or development of an organ or tissue, with increase in cell size but without increased cell division  See) hyperplasia

hypha (Pl. hyphae): thread-like structure in fungi that produces enzymes to break down living or dead organisms; the fine, branching tubes which make up the body (or mycelium) of a multicellular fungus

hypolimnion: cool, oxygen-deficient, bottom layer in a stratified body of water (usually a seasonal phenomenon).

hypothalamus: endocrine gland at the base of the brain that controls body temperature, water balance, appetite, and sleep

hypothesis: rational, untested explanation for a phenomenon, usually derived from reason and experience

hypoxia: condition of low dissolved oxygen in aquatic systems

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immune system: body's defense system against disease

immunity: body's ability to fight off disease without becoming sick

inbreeding: breeding that involves crossing plants or animals that have the same or very similar sets of genes

incisor: front tooth used for biting

incomplete dominance: condition that occurs when a gene is neither dominant nor recessive

incubate: warm eggs by sitting on them until they hatch

infection: state caused when the body is iiivaded by disease-causing organisms

infectious disease: disease that is transmitted among people by harmful organisms such as viruses and bacteria; communicable disease

inflammation: a type of nonspecific immune response to irritation, injury, or infection cuased by disease-causing organisms, which results in redness, warmth, swelling and pain Technical) immune system components are directed to the site and made manifest by increased blood supply and vascular permeability which allows chemotactic peptides, neutrophils, and mononuclear cells to leave the intravascular compartment. Microorganisms are engulfed by phagocytic cells in an attempt to contain the infection in a small-tissue space. The response includes attraction of phagocytes in a chemotactic gradient of microbial products, movement of the phagocyte to the inflammatory site and contact with the organism, phagocytosis (ingestion) of the organism, development of an oxidative burst directed toward the organism, fusion of the phagosome and lysosome with degranulation of lysosomal contents, and death and degradation of the organism. When quantitative or qualitative defects in neutrophil function result in infection, the infection usually is prolonged and recurrent and responds slowly to antimicrobial agents. Staphylococci, gram-negative organisms, and fungi are the usual pathogens responsible for these infections.
History) defining clinical features of inflammmation have been known since antiquity and first recorded by Celsus (Aulus Aurelius Cornelius, 30 BC - 45 AD), Roman physician and medical writer: Latin rubor=>redness, calor=>warmth), tumor=>swelling) and dolor=>pain.

inheritance: a trait acquired via biological heredity passing from parent or ancestor to offspring or heir

ingestion: taking in food; eating

inhale: breathe in

insulin: polypeptide hormone that regulates the metabolism of glucose, fats and proteins; produced in the pancreas by cells in the islets of Langerhans.  Uses) mass-produced for the treatment of diabetes mellitus with the aid of genetically engineered bacteria or is taken from pigs and cattle

interface: boundary between two immiscible phases, sometimes including a thin layer at the boundary within which the properties of one bulk phase change over to become the properties of the other bulk phase. When one of the phases is a gas, the term surface is frequently used.

interferon: substance produced by a body cell when invaded by a virus

interleukin: family of proteins controlling aspects of blood cell and platelet (hemopoiesis) production and immune response. Eight interleukins are currently characterized
Examples) interleukin 2 stimulates T-lymphocytes and is being studied for possible cancer treatment

intermittent stream: watercourse that flows only at certain times of the year; a watercourse where water losses from evaporation or seepage exceed available stream flow.

internal fertilization: fertilization that takes place inside the body of the female

interneuron: neurons involved in intermediate processing of signals that connect only with other neurons, generally with sensory and motor neurons (not with either sensory cells or muscles).

interphase: period between one mitosis and the next

interstitial: relating to spaces or interstices in any structure, eg, small area, space or hole in the substance of an organ or tissue

intravascular fluid: body fluid inside the blood vessels, including blood cells and the plasma

invertebrate: animal without a backbone

in vitro: literally, "in glass"; a biologic or biochemical process occuring outside a living organism.

iris: circular, colored portion of the eye that regulates the amount of light entering the eye

Islets of Langerhans: groups of specialized cells in the pancreas that make and secrete hormones, the five types of cells in an islet and their associated hormones are: alpha/glucagon; beta/insulin; delta/somatostatin, PP and D1 (about which little is known)  Symptoms) degeneration of the insulin-producing beta cells is the main cause of type I (insulin-dependent) diabetes mellitus  History) named after Paul Langerhans (1847-1888), the German pathologist who discovered them and described their appearance as little islands in 1869

isotopes: atoms containing the same number of protons but different numbers of neutrons, ie, two or more forms of atoms of the same element with different masses

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joint: place where two bones meet

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kidney: organ in the urinary tract that removes waste products from the blood and produces urine; one of a pair of bean-shaped, major excretory organs that are located in the lower back on both sides of the abdomen that filter waste and toxins from, and regulate concentration of acid and chemicals in the blood (such as hydrogen, sodium, potassium, and phosphate) as well as maintain water balance in the body by excreting urine. They also make substances that help control blood pressure and regulate the formation of red blood cells. Urine collects in the middle of each kidney, an area called the renal pelvis. Urine passes from the kidneys through connecting tubes (ureters) into the bladder, where it is stored until excreted.

kilogram (kg): basic unit of mass in the metric system

kinetochore: platelike structure necessary for chromosomal movement during mitosis; it develops on the centromere and links the chromosomes to the mitotic spindle

kingdom: topmost and largest taxonomy rank, immediately above phylum or division
See) Monera, Protista, Fungi, Plantae, Animalia

Krebs cycle (citric acid cycle, tricarboxylic acid cycle): series of reactions following glycolysis in aerobic respiration that convert pyruvic acid into hydrogen, carbon dioxide and electrons

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land plant: bryophytes (nonvascular) and tracheophytes (vascular) are the two types recognized by plant scientists

large intestine: organ in the digestive system in which water is absorbed and undigested food is stored

larva: stage of insect that develops from an egg

larynx: voice box

law: scientific theory that has been tested many times and is generally accepted as true

leaching: process of separating the soluble components (at times nutritive or harmful elements) from some material (eg, soil) by percolation

legume: member of the bean or pea family Fabaceae; a type of dry fruit whose pod forms from one carpel and opens from both sides

lens: curved piece of glass that bends light rays as they pass through it; part of the eye that focuses the light ray coming into the eye

lentic: still or standing water

leukocyte: (alt. white blood cell) pale, nucleated cell in the immune system that destroys invading cells and removes debris  See) also granulocyte, lymphocyte, and monocyte.

lichen: organism made up of a fungus and an alga that live together in a symbiotic relationship

life span: maximum length of time an organism can be expected to live

ligament: stringy connective tissue that holds the bones together

ligand: neutral molecule or ion having a lone pair of electrons that can form a bond with a metal ion

limiting factor: living or nonliving factor in an environment that can stop a population from increasing in size

limiting nutrient: nutrient present in lowest concentration relative to need: limits growth such that addition of the limiting nutrient will stimulate growth.

lipophilic: having an affinity for fatty tissues

liter (L): basic unit of volume in the metric system

litter: material that is disposed of in improper places

liver: large glandular and vascular organ in the visceral cavity of all vertebrates (upper abdomen of humans, beneath the diaphragm, to the right of center) that aids in digestion (secretes bile into the small intestine to break down fats for better absorption), stores and processes various nutrients, eg, breaks down glycogen into glucose when blood glucose is low, and detoxifies of the blood (by removing waste products and worn-out cells and concentrating the toxins within bile which is secreted into the small intestine for later excretion); most venous blood from the alimentary canal passes through it on the way back to the heart; in invertebrates, it is usually made up of caecal tubes, and differs in form and function from that of vertebrates

livenvort: small, green nonvascular plant with flat leaflike parts

lotic: flowing water

lung: main respiratory organ

lymph: clear fluid plasma that leaks out of the blood and surrounds and bathes tissues and the outside of body cells and is collected, filtered, and transported by the lymphatic system to the blood circulatory system.

lymphatic system: tissues and organs, including the bone marrow, spleen, thymus, and lymph nodes, that produce and store cells that fight disease and infection; lymphatic tissues such as vessels, lymph nodes [filter function], and spleen, which collect, filter, and transport lymphatic fluid from tissues and capillaries, then return it to the blood circulatory system.

lymphatic tissue: (alt. lymphoid tissue) lymphocytes within a network of fibers; part of the lymphatic system

lymph nodes: (alt. lymph glands) small, bean-shaped organs located throughout the lymphatic system that store cells that can trap cancer cells or bacteria traveling through the body in lymph. round or oval mass of lymphatic tissue which filters lymphatic fluid found on a lymphatic vessel within the lymphatic system, draining tissues where immune responses are initiated

lymphocyte: small non-granular white blood cell (leukocyte) of the immune system, usually found in lymphatic tissue, that responsible for immune responses. The two main types of lymphocytes are B cells and T cells. B cells make antibodies that attack bacteria and toxins. T cells attack a body's own cancerous or virus stricken cells. Lymphocytes secrete products (lymphokines) that modulate the functional activities of many other types of cells and are often present at sites of chronic inflammation.

lymphokines: molecules other than antibodies which are involved in signalling between cells of the immune system and are produced by lymphocytes  See) interleukins.

lysogenic bacteria: (Pl. ...bacterium) bacterium containing in its genome the DNA of a dormant virus. The (lysogenic) virus passively allows itself be replicated by the bacterium but can reactivate (becoming a lytic virus) and destroy the bacterium at any time.

lysosome: small, round structure involved in the digestive activities of a cell

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macroalgae: multicellular algae (green, blue-green, red) with filamentous, sheet or mat-like morphology.

macronucleus: large nucleus in a paramecium that controls all life functions except reproduction

macrophage: large leukocyte that travels in the blood but can (wandering macrophage) leave the bloodstream and enter tissue; like other leukocytes, it protects the body by digesting debris and foreign cells.

macrophyte: a multicellular aquatic plant, either free-floating or attached to a surface; macroscopic vascular plant

malignant: life-threatening

mammary gland: structure in a female mammal that produces milk

mantle: part of a mollusk that produces material that makes up the hard shell

marine biome: ocean biome

marrow: soft material inside a bone

marsupial: pouched mammal

mass: measure of the amount of matter in an object

matter: anything that takes up space and has mass

mechanical digestion: physical action of breaking down food into smaller pieces

mechanoreceptors: specialised (transducer) cells that transduce mechanical stimuli and relay that information centrally in the nervous system.  Examples) hair cells, which mediate hearing and balance, and the various somatosensory receptors, often with non-neural accessory structures.

medulla: part of the brain located at the base of the brain stem that controls involuntary body processes

meiosis: cell division in specialized tissues of ovaries and testes in animals resulting in the production of sperm or ova, respectively. Meiosis involves two divisions and results in four daughter cells, each containing only half the original number of chromosomes. These cells can develop into gametes.
See) mitosis


menopause: physical change in females after which menstruation and ovulation stop

menstrual cycle: monthly cycle of change that occurs in the female reproductive system

menstruation: process in which the blood and tissue from the thickened lining of the uterus pass out of a female's body through the vagina

mesocosm: field-scale model utilized to understand the interactive relationship of microbial communities and the roles played by microbial populations within ecosystems


Mesozoic [Gr.=>middle life]: second era of the Phanerozoic eon of geologic time between the Paleozoic and the Cenozoic eras, and containing the Triassic, Jurassic, and Cretaceous periods; During this time the fauna changed drastically compared to the Paleozoic. This early Mesozoic was dominated by ferns, cycads, ginkgophytes, bennettitaleans, and other unusual plants. Modern gymnosperms, such as conifers, first appeared in their current forms in the early Triassic. By mid-Cretaceous, the earliest angiosperms had appeared and began to diversify, largely taking over from the other plant groups. Dinosaurs, which are perhaps the most popular organisms of the Mesozoic, evolved in the Triassic, but were not very diverse until the Jurassic. Except for birds, dinosaurs became extinct at the end of the Cretaceous. Some of the last dinosaurs to have lived are found in the late Cretaceous deposits of Montana in the United States.
Time) 248 to 65 million (180 million) years

messenger RNA (mRNA): RNA that carries a copy of a specific sequence of genetic information (a gene) from the DNA in the cell nucleus to the ribosomes in the cytoplasm where it is translated in order to synthesize a protein. Messenger RNA is assembled on one sequence (one strand) of DNA bases.

metabolism: chemical changes in living systems by which energy is provided for vital processes and activities and new material is assimilated; all chemical activities in an organism.

metabolite: chemical intermediate in metabolic reactions

metamorphosis: change in appearance due to development; changes through which an insect passes in its growth from the egg through the larva, pupa and adult

metaphase: second stage of mitosis

Metazoans: all animals having an adult body composed of numerous cells differentiated into tissues and organs and usually a digestive cavity lined with specialized cells. Taxonomy) usually includes the Coelenterata and all higher animals but sometimes extended to include the Parazoa and Mesozoa.

meter (in): basic unit of length in the metric system metric system: universal system of measurement

methanotroph: methane-oxidizing bacterium

microaerophiles: bacteria which require low concentrations of oxygen and don't do well either at atmospheric oxygen concentrations or without oxygen Examples) Sphaerotilus natans, Enterobacter aerogenes.

microbial ecology: study of the interactions of microorganisms with their biotic and abiotic surroundings

microbiology: study of microorganisms or microscopic forms of life (bacteria, protozoa, viruses, and fungi)

micron (micrometer): or one millionth (10-6) of a meter, sometimes represented by the Greek letter µ (mu). A micron is 0.000039".  Examples) bacteria; contaminant particles are measured by micron size and count.

micronucleus: small nucleus that controls reproduction in a paramecium One of two cellular nuclei in the single-celled ciliated protozoan "tetrahymena" containing a full set of the organism's genes. It is used only under stressful conditions whereby the it directs the tetrahymena to undergo sexual reproduction with another stressed tetrahymena, producing four identical offspring with mixed parental genes.

microorganism: organism of microscopic or ultramicroscopic size

microscope: instrument that produces an enlarged image of an object

migrate: move to a new environment during the course of a year

mineral: simple substance found in nature that helps maintain the normal functioning of the body

mineralization: microbial breakdown of organic materials into inorganic materials

mineralocortoid mineralocortoid: chemical that regulates the level of minerals such as sodium and potassium in the blood

mitochondrion (Pl. mitochondria): rod-shaped structure (many) in the cytoplasm that produce a source of energy (adenosine triphosphate, ATP) for the cell and contains a small amount of DNA, distinct from that of chromosomes, and normally inherited from the mother.

mitosis [Latin mitis=>mild, gentle; ripe, mature]: cell division process that occurs in somatic cells. One cell divides into two offspring cells that are identical to each other in their chromosome complement. Mitosis produces cells with diploid numbers of chromosomes  alt.) duplication and division of the nucleus and of the chromosomes during cell reproduction.
See) meiosis


mole: (abbrev mol) fundamental unit for measuring compounds; one gram molecular weight of a compound  See) Avogadro's number.

molecular clock: scale used to estimate the rate of change in proteins over time

molecule: smallest particle of a compound having all the properties of that compound

molecular weight: mass of one molecule of a nonionic substance in atomic mass units

mollusk: invertebrate with a soft, fleshy body that is often covered by a hard shell

molt: periodically shed one's skin

Monera: (prokaryotes, monerans) prokaryotic Kingdom composed of bacteria (to include archaebacteria, eubacteria) and cyanobacteria. One-celled (sometimes colonial) organisms whose cells lack a nuclear envelope, mitochondria, or plastids. They reproduce asexually through fission (splitting in two) and mainly gain their nutrition by absorbing it from their environment (though some species are chemoautotrophs or photosynthetic). Members of this kingdom were among the first forms of life over 3.5 billion years ago. Some biologists believe archaebacteria should be a separate sixth taxonomic Archaea Kingdom.

moneran: member of the Monera kingdom

monoclonal antibody: substance produced by the joining of cancer cells with antibody-producing white blood cells

monomer: single molecule that is the subunit of a polymer

monophyletic: group of organisms that includes the most recent common ancestor and all of the descendants of that most recent common ancestor. A monophyletic group is called a clade  alt. ) of or pertaining to a single family or stock, or to development from a single common parent form; as opposed to polyphyletic

monosaccharide: the simplest sugar  Chemistry) composed of one carbon atom for every two hydrogens and one oxygen

monotreme: egg-laying mammal

morphology: form and structure of an organism or part of an organism; the study of form and structure

moss: small, green nonvascular plant that has stemlike and leaflike parts

motor neuron: type of neuron that connects functionally to a muscle fibre and carries messages from the central nervous system to effectors

multiple allele: more than two alleles that combine to determine a certain characteristic

multicellular: having many cells

muscle tissue: type of tissue that has the ability to contract and make the body move

mutant: organism bearing a mutant gene that expresses itself in the phenotype of the organism an organism, population, gene, or chromosome, etc. which differs from the corresponding wild type by one or more mutations

mutation: change in geiies or chromosomes that causes a new trait to be inherited

mutualism: stable symbiotic relationship between organisms of different species that is mutually beneficial  alt.) sometimes referred to same-species relationsip, such as colonial animals sharing food
Examples) symbiotic gut fauna in ruminants, such as cows

mycelium (pl. mycelia; also thallus, pl. thalli): the diffuse, indefinite body of a multicellular fungus, which is composed of many fine, branching tubes called hyphae.

mycobacterium tuberculosis: pathogenic gram-positive bacillus (type of bacterium) that causes tuberculosis

mycoplasmas (mycoplasmal contamination): the smallest cells or microorganisms known (usually .3 to .8 micrometers), able to pass through most filters and often contaminating normally sterile preparations like cultures and vaccines. Some types of mycoplasmas cause pneumonia. is an important problem in biotechnology, but fortunately the microbes can .  Prevention) usually killed with antibiotics

mycotic infection: disease caused by a fungus

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natural immunity: immunity that is present at birth and protects people from some diseases that infect other types of organisms

natural resource: material produced by the environment and used by people

natural selection: survival and reproduction of those organisms best adapted to their surroundings

nematocyst: stinging cell that is found in the mouth of a coelenterate

nematode: nonsegmented roundworm (animal), parasitic on plants or animals, or free living in soil or water

neoplasm: new or abnormally fast growth of cells that may create a benign or cancerous tumor

nephron: microscopic chemical filtering factory in the kidneys

nerve impulse: message carried throughout the body by nerves

nerve tissue: type of tissue that carries messages back and forth between the brain and spinal cord and to every part of the body

nervous system: body system that controls all of the activities of the body

neuron [Greek=>a sinew, tendon, thong, string, or wire] { Figure }: specialized nerve cell (electrical impulse conducting unit of the nervous system) connected to other types of neurons by synapses; can react to stimuli and transmit impulses electro-chemically; has a nucleus, axons to emit chemical output which is received by dendrites of other neurons connected to it, and dendrites to receive chemical input from axons of other neurons connected to it; some of the longest (up to several meters) cells known; send output signals to muscles or other neurons, including motoneurons (muscle or motor neurons) and receive input signals from other neurons, including sensory neurons. A neuron that strictly signals another neuron is called an interneuron.
History) word coined by English physiologist Sir Charles Scott Sherrington, Oxford University (1857-1952), an influential figure in the development of neurophysiology, clinical neurology and neurosurgery (brain surgery); coined other useful terms including synapse; shared the 1932 Nobel Prize in Medicine or Physiology with Lord Edgar Douglas Adrian of Cambridge University for discoveries of neuron functionality.

neurotoxins: poisons that affect the nervous system of an animal

neurotransmitter: chemical released from the axon of one neuron which triggers a nerve impulse by binding to a site in the dendrite of an adjacent neuron

neutron: subatomic particle that has no charge but with a mass approximately the same as that of a proton; found in all atoms except the lightest hydrogen isotopes

niche: role of an organism in its community or environment


nitrogen cycle: cyclic tranformation of the element nitrogen from gaseous forms to inorganic forms, such as ammonium, nitrates and nitrites, and to organic forms, such as nucleic acids and proteins and back to elemental nitrogen

nitrogen fixation: process by which some kinds of bacteria take gaseous nitrogen (N2) directly from the air and form nitrogen compounds available for plant uptake
See) nitrogen cycle

nitrogenous base: nitrogen-containing molecule having the chemical properties of a base  See) purine and pyrimidine

nondisjunction: failure of chromosomes to separate during meiosis

nonrenewable resource: natural resource that cannot be replaced by nature

nonvascular plant: plant lacking transportation tubes that carry water and food throughout the plant

nostril: opening in the nose

notochord: rudimentary internal skeleton of stiff cartilage running lengthwise under the dorsal surface of chordates; generally, there is a single hollow nerve chord on top of the notochord. Among humans and the other vertebrates, the notochord is replaced following the embryonic stage.

nuclear energy: energy located within the nucleus of an atom

nuclear fission: process in which atoms of the element uranium are split to release energy

nuclear fusion: process by which atoms are combined and energy is released

nuclear membrane: thin membrane that separates the nucleus from the rest of a cell

nucleic acid: genetic material of all living organisms; large organic compound composed of nucleotide subunits. Examples) DNA and RNA.

nucleolus (nucleoli): cell structure located in the nucleus and made up of RNA and protein

nucleoplasm (karyolymph): fluid within the nucleus of a eukaryote containing chromosomes and nucleoli

nucleotide: a subunit of an DNA or RNA molecule, in (either of) which thousands are linked. It consists of a nitrogenous base, a phosphate molecule, and a sugar molecule (deoxyribose in DNA and ribose in RNA). The nitrogenous bases adenine, guanine, cytosine are contained in both DNA and RNA, in addition DNA contains thymine and RNA contains uracil

nucleus: (Pl: nuclei) cell structure that directs all the activities of the cell. Cellular organelle in eukaryotes that contains the genetic material. Chemistry: very small, very dense, positively charged center of an atom containing protons and neutrons, as well as other subatomic particles.

nutrient: usable portion of food

nymph: intermediate growing stage in the life cycle of an arthropod with an incomplete metamorphosis, usually having much the same morphological appearance as an adult.

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obligate aerobes (strict aerobes): bacteria which require the presence of oxygen to survive. Examples) Pseudomonas fluorescens

obligate anerobes (strict aerobes): bacteria for which the absence of oxygen is required, ie, oxygen is toxic to the cells. Examples) Clostridium botulinum, C. tetani.

obligate parasite (biotroph): organism that can grow only as a parasite in association with its host plant; cannot be grown in artificial culture media

occlusion: block or plug that stops flow of liquids (as in vessels)

oil: energy-rich substance

omnivore [Latin omnis: all, every]: organism that eats both plants and animals

ontogeny: history of the development and growth of the individual organism

Oomycetes: fungal-like organisms typically with nonseptate mycelium, asexual sporangia and zoospores, and sexual oospores

oospore: thick-walled, sexually-derived resting spore of Oomycetes

opiate: pain-killing drug produced from the opium poppy

oral groove: indentation in a paramecium through which food particles enter

order: fourth classification in the taxonomic sequence, between class and family
Examples) Animal: Chordates: Mammalia: Carnivora - carnivores; Animal: Chordates: Mammalia: Insectivora - insect-eaters

organ: group of different tissues working together; third level of organization in an organism

organ of corti: organ containing the special sensory receptors for hearing. It is composed of a series of epithelial structures placed upon the inner part of the basilar membrane

organelle: membrane-bound body found in the cytoplasm of the cell that performs specific cellular functions; intracellular structures of an organism that together carry out all the basic life functions; specialized part of a cell, analogous to an organ.  Examples) mitochondria and chloroplasts

organ system: group of organs that work together to perform certain functions; fourth level of organization in an organism

organic: any molecule containing carbon atoms; pertaining to living organisms

organism: any living thing

osmosis: special type of diffusion by which water passes into and out of the cell

ossification: process in which cartilage disappears and is replaced by bone

ovary: the female reproductive structure of organisms; in plants, enlarged basal portion of a pistil, containing the ovules and developing into the fruit; hollow structure that contains the egg cells of a flower; in animals, the female gonad producing eggs (ova) and sex gland (endocrine gland) producing female hormones; in women, these hormones regulate the menstrual cycle and pregnancy, and control development of characteristics such as breasts, body shape and hair and the pair of ovaries are located in the pelvis, one on each side of the uterus, each the size and shape of an almond. An egg is released during each menstrual cycle and travels through a fallopian tube to the uterus.

over-the-counter drug: drug that can be bought without a prescription

oviduct: Fallopian tube; tube through which an egg travels from the ovary

ovulation: process in which an egg is released from the ovary into the Fallopian tube

ovule: enclosed structure that, after fertilization, becomes a seed; egg contained within an ovary; structure that contains the female sex cells of a seed plant

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paleontology: scientific study of extinct organisms through the examination of fossils.

Paleozoic [Gr.=>old life]: era of geologic time, from the end of the Precambrian (or the end of the Proterozoic eon) to the beginning of the Mesozoic era, and containing the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian periods. This was the first era to exhibit a proliferation of the complex life-forms. At its beginning, almost all living animal phyla appeared within a few million years. About halfway through the fungi, plants, insects and animals colonized the land and limestone formations were deposited. At its end 90% of marine animal species were wiped out, marking the largest mass extinction in the earth's record. The coal deposits of western Europe and the eastern United States were formed during this era. The Paleozoic took up over half of the Phanerozoic eon, during which there were six major continents (each consisting of different parts of the modern continents) which experienced tremendous mountain building along their margins and numerous incursions and retreats of shallow continental seas across their interiors, as evidenced by the resulting large limestone outcrops.
Time) 544 - 248 (span 300) million years

palisade layer: long, cylindrical food-making cells of the upper mesophyll in a leaf

pancreas: organ behind the lower part of the stomach that produces insulin and pancreatic juice in areas called the islets of Langerhans, which contain specialized cells that manufacture respective hormones

pancreatic juice: colorless alkaline digestive fluid secreted intermittently by the pancreas containing enzymes trypsin, chymotrypsin, and carboxypolypeptidase

paramecium (Pl. paramecia; alt. ciliates) [genus]: single-celled, slipper-shaped, fast moving protozoan covered with cilia used for motility, contractile and food vacuoles, a mouth near the center, and a pellicle covering the outer surface which helps keep its shape  Taxonomy) kingdom Protista, phylum Ciliophora

paraphyletic: group of organisms that includes the most recent common ancestor of all of its members but not all of its descendents (distinction from polyphyletic groups not absolutely clear.)

parasite: organism that feeds on other living organisms

parasitism: symbiotic relationship in which one organism is harmed by the other organism

parathyroid: endocrine gland producing a hormone that controls the level of calcium in the blood

pasteurization: process in which milk is heated to destroy the bacteria that would cause the milk to spoil quickly

pathogenic bacteria: bacteria capable of causing disease.
Examples) Bacillus anthracis (anthrax), Bordetella pertussis (whooping cough), Corynebacterium diphtheriae (diphtheria), Cryptosporidium, Mycobacterium tuberculosis (tuberculosis), Salmonella sp. (salmonellosis and typhoid fever), Shigella sp. (bacillary dysentery), Streptococcus pyogenes (scarlet fever), Vibrio cholerae (cholera), Yersinia pestis (bubonic plague)  See) waterborn disease

pellicle: hard membrane that covers the outer surface of a paramecium

penicillin: substance produced by fungi which is able to inhibit bacterial growth
History) discovered in 1926 by Alexander Fleming

pepsin: enzyme produced by the stomach that digests protein

peptide: any of a class of molecules that hydrolyze into amino acids and form the basic building blocks of proteins.

peptide bonds: amide linkage between amino acids by way of a bond formed between the amino group of one amino acid and the carboxyl group of another


Periodic Table of Elements { Table }:
{ History article }

periosteum: tough membrane containing bone-forming cells and blood vessels that surrounds the solid bone

peripheral nervous system: part of the nervous system that branches Out from the central nervous system and includes a network of nerves and sense organs

periplasmic space: in gram-negative bacteria, the area between the cytoplasmic membrane and cell wall containing nutrition-related enzymes

peristalsis: powerful wave of muscle contractions that pushes food through the digestive system

permafrost: permanently frozen tundra soil

permeable membrane: membrane that allows substances to pass through it

pesticide: chemical used to kill harmful insects or other pests

petal: colorful leaflike structure that surrounds the male and female reproductive organs In a flower

petroleum: liquid fossil fuel

pH: a measure of acidity or alkalinity of a solution or mixture. It is the negative log of the Hydrogen potential (which the letters "pH" represent).

pH = -log (H+)

where (H+) is the concentration of hydrogen ions in units of moles per liter of volume. A pH of 7 is neutral and indicates that there are 10-7 moles per liter of H+ ions in a solution.

phago- (prefix) [Gr. phago=>to eat]: eating, devour
Examples) phagocyte, phagophobia

phagocyte: (Gr. to eat + a hollow vessel, ie, cell) leukocyte which plays a part in retrogressive processes by taking up (eating), in the form of fine granules, the parts to be removed. The human macrophage and neutrophil are phagocytes.

phagocytosis: process by which phagocytes engulf and ingest bacteria or other foreign bodies by enclosing it within a vacuole (phagosome) in the cytoplasm

phagophobia: excessive fear of eating

phanerogam: plant reproducing by seeds and having conspicuous reproductive parts.
See) cryptogam

Phanerozoic: [=>ancient]: last eon of geologic time with an abundance of complex life forms (following Precambrian) beginning with the Cambrian period of the Paleozoic era, through the Mesozoic era and into the current Cenozoic era; 544 million years to present

phenotype: visible characteristic of an organism

pheromone: chemical substance given off by insects and other animals to attract a mate

phospholipid: triglyceride that has a phosphorous-containing compound bound to it in place of one of the three fatty acids

phloem: tubelike plant tissue in the conducting system of a plant that carries food or metabolites (products of chemical reactions in the plant, such as sugars)

photosynthesis: constructive metabolism [in chloroplasts of organisms] which uses energy from light or natural sunlight to make (synthesize) food, whereby carbon dioxide from the air and water are converted into carbohydrates and oxygen in the presence of chlorophyll  Examples) occurs in plants, algae, cyanobacteria and lichens.

phototaxis: ability of bacteria to detect changes in light intensity and respond by moving away from or toward the light.

phototropism growth-mediated response of plants or microorganisms to stimulation by visible light

phylogenetics (phylogenetic analysis) [a type of systematics]: scientific study and discovery of the evolutionary or genetic relationships between organisms and of the causes behind these patterns, including methods of collecting, analyzing and interpreting data and results; may entail the application of cladistics; may be referred to as a type of taxonomy, which is a more general term for classification by characteristics which may not necessarily be derived characteristics

phylogeny (phylogenesis, phylogenetic, phylogenic): evolutionary relationships among organisms; the branching patterns produced by their true evolutionary history; evolutionary tree or history of a particular taxonomic group of organisms, usually a group of species assumed to be descended from a common ancestral species.
Context) "the phylogeny of the group.."

phylum (division, Pl. phyla): second classification in the taxonomic sequence, between kingdom and class
Examples) animal kingdom: chordates division; plant kingdom: antrophyta division (>flowering plants)

physical dependence: effect of drug abuse in which the body cannot function properly without the drug

physiological adaptation: difference in physical and chemical activities of cells and tissues of a species, which improves the probability of its survival under the conditions of its environment

physiological ecology study of biophysical, biochemical, and physiological processes used by living organisms to cope with factors in their physical environment and which are employed during ecological interactions with other organisms.

phytoplankton: plankton that are photosynthetic

pistil: female reproductive organ of a flower  See) stamen.

pituitary: endocrine gland located below the hypothalamus that produces hormones that control many body processes

placenta: structure through which developing mammals receive food and oxygen while in the mother

plankton: small (often microscopic) organisms that float, drift or swim near the surface of fresh or salt water  Examples) phytoplankton, zooplankton

plants:  See) green plants

plasma: the fluid portion of blood or whole blood minus the cells, yellowish in color; clinically obtained by removing the blood cells from blood  alt. ) fire-like, highly energetic gas made up of ions, electrons, and neutral particles

plasmacyte (plasma cell): non-granular, basophilic leukocyte that produces antibodies

plasmagene: any self-replicating gene in cytoplasm, including DNA found in the mitochondria

plasmalogen: glycerol-based phospholipids usually found in brain and spinal cord tissue

plasma proteins: proteins dissolved or suspended in blood plasma  Examples) albumin

plasmid: bacterial DNA in the form of a ring, autonomously replicating, extrachromosomal; distinct from the normal bacterial genome, nonessential for cell survival under nonselective conditions, some capable of integrating into the host genome  Uses) artificially constructed plasmids are used as cloning vectors

platelet: blood cell fragment that aids in blood clotting

pleura: very thin, transparent membrane covering both the outer surface of the lungs and diaphragm and the inner surface of the chest wall

pollen: contains the male sex cells of a seed plant

pollination: transfer of pollen from the male part to the female part of a flower

pollution: introduction of harmful or unwanted substances into the environment

polymer: large molecule (generally molecular weight >=10,000) that is made by linking many many similar smaller molecules (monomers) into a "chain." A polymer can be a homopolymer made of a single monomer species or a copolymer made of different monomers. Biopolymers are created naturally. Polymers are also organically synthethized for industry and research.

polypeptide (protein): a polymer required to make a protein, which is composed of multiple amino acid units linked by peptide bonds; usually less than 100 amino acids long; formed during translation

polyphyletic: a group of organisms that does not include their most recent common ancestor which does not possess the character shared by members of the group (the distinction from paraphyletic groups is not absolutely clear) alt. ) pertaining to, or characterized by, descent from more than one root form, or from many different root forms; polygenetic as opposed to monophyletic

polysaccharides: carbohydrates made of chains of simple sugars

population: group of the same type organism living together in the same area

pore: opening on the outer surface of an animal through which materials enter or leave

poriferan: member of the phylum portifera


Precambrian [=>before Cambrian]: Time span from the beginning of the earth to the beginning of the Paleozoic era of the Phanerozoic eon. This includes about 90% of all geologic time (this excludes the Hadean eon which predates geologic time) and contains the Hadean, Archaean and Proterozoic eons.
Time) 4.5 billion - 544 million (span 4 billion) years

predator: animal that kills and eats other animals

predation: relationship that exists between a predator and its prey

prescription drug: drug that requires a doctor's prescription

prey: animal that is killed and eaten by a predator

primate: order of mammals that includes humans, apes, and monkeys

primitive character state (primitive characteristic or primitive condition): character state that is present in the common ancestor of a clade; inferred to be the original condition (vs. a derived condition) of that character within the clade under consideration.
Examples) presence of hair is a primitive character state for all mammals, whereas hairlessness of whales is a derived state for one subclade within Mammalia

prion (slow virus): communicable infective agent (proteinaceous infectious particle) which is a protein normally occurring in a harmless form, but by folding into an aberrant shape turns into a rogue agent which coopts other normal prions to become rogue prions; disease-causing agent containing no genetic material (no detectable nucleic acid) that is neither bacterial, fungal nor viral with slow replication and long latent intervals in the host
Examples) scrapie, bovine spongiform encephalopathy (BSE); associated with a number of degenerative brain diseases, including mad cow disease, Creutzfeld-Jacob disease, fatal familial insomnia, kuru, Gertsmann-Straeussler-Scheinker disease, and possibly some cases of Alzheimer's disease   History) Dr. Stanley B. Prusiner received the 1997 Nobel Prize in physiology or medicine for the discovery of prions

probability: numerically evaluated likelilood that an event may or may not take place

prokaryote: (procaryote, prokaryotic, procaryotic cell) cell or organism that maintain their genome dispersed throughout the cytoplasm and lacking a membrane-bound, structurally discrete nucleus and other subcellular compartments; the chromosomal DNA is circular, and the entire genome is carried on one chromosome Taxonomy) not used in any formal system, but previously used interchangeably with the term bacteria. Examples) Bacteria  See) eukaryote, chromosomes, Monera.

prokaryotic cell: cell structure of prokaryotes, which lacks a true nucleus and divides by simple fission rather than mitosis. See) eukaryotic cell

producer: organism that can make its own food

promoter: substance that in very small amounts can increase the activity of a catalyst; a DNA sequence that directs RNA polymerase to bind and initiate, transcription of genes or operons.

prophase: first stage of mitosis during which the nuclear membrane begins to disappear

protein: substance (generally of molecular weight greater than 10,000) used to build and repair cells; made up of polymers of amino acids linked by peptide bonds. The specific sequence of amino acids determines the shape and function of the protein. Examples) enzymes, hormones, and antibodies

Proterozoic Eon [=>early life]: final eon of Precambrian geologic time during which primitive single celled and more advanced multicellular organisms begin to appear as indicated by abundant fossils in rocks from this eon; 2.5 billion and 544 million years; precedes the Phanerozoic eon

Protista kingdom (protists): biologic kingdom composed of eukaryotic organisms which are not animals, true fungi or green plants, may reproduce sexually or asexually and may obtain nutrition via several methods, including photosynthesis, ingesting other organisms, and absorption. Protists can be sedentary or move with pseudopods, flagella, or cilia and include unicellular and multicellular algae, slime molds, and unicellular or simple colonial protozoans. Taxonomy) non-monophyletic adaptive groups: Flagellates, Amoebae, Algae, Parasitic Protists. Examples) one group of Protists, the Stramenopiles include fungal-like organisms (Oomycetes), parasitic protozoa (opalines and Blastocystis), free-living protozoa (some heliozoa and flagellates) as well as various unicellular algae (chrysophytes) and muticellular algae (kelps and other brown algae). Species) >200,000 named.

proton: subatomic particle in the nucleus of an atom having a mass of 1.0073 amu and a charge of +1

protoplasm: all of the living materials of which a cell is made

protozoan: microscopic, unicellular, motile, animal-like (often aerobic) eukaryotic organism of the Protista kingdom. They occur as free-living species or as parasites and commensals of plants and animals. Diseases, such as African sleeping sickness, malaria, and dysentery are caused bt protozoans. They sometimes cluster into colonies and often consume bacteria as an energy source.

pseudopods: finger-like extensions of a sarcodine, composed of its cytoplasm, which are used for mobility and phagocytosis

psychological dependence: emotional need for a drug

ptyalin: enzyme in saliva that breaks down some starches into sugars

puberty: beginning of adolescence

pulmonary: relating to the lungs and pleura

pulmonary artery: artery which transports oxygen-poor blood from the heart to the lungs, where the blood picks up oxygen; one of the few arteries which is blue instead of red

punctuated equilibrium: theory that evolution occurs in rapid and sudden changes in a species after a long period of little or no change

pupa (pl. pupae): inactive stage between the larva and adult stage in the life of an insect having complete metamorphosis

pupil: circular opening at the center of the iris

purine: double-ring nitrogenous base occurring in nucleic acids. The purines in DNA and RNA are adenine and guanine.

pus: white substance in an infected area made up of dead bacteria, destroyed body cells, and dead white blood cells

pyrimidine: single-ring nitrogenous base occurring in nucleic acids. The pyrimidines in DNA are cytosine and thymine. The pyrimidines in RNA are cytosine and uracil.

pyruvate: can be aerobically degraded by the Krebs or TCA cycle to produce large amounts of ATP

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radially symmetrical: having parts symmetrically arranged about a central axis


radioactive dating: method based on radioactive elements used by scientists to measure the age of fossils or the age of the rocks in which fossils are found

radioactive material: material harmful to life, that is given off during the nuclear fission process

radula: filelike structure in the mouth of a univalve used to scrape food from an object

receptor: part of the nervous system that responds to stimuli; cell-surface proteins that trigger intracellular changes

recessive: weaker trait in genetics

recombinant DNA: new piece of DNA produced by combining parts of separate DNA strands

red blood cell: cell that carries oxygen throughout the body

reflex: automatic reaction to a stimulus

regeneration: ability of an organism to regrow lost parts

regulatory elements: relatively short nucleotide sequences in DNA that play important roles in controlling gene expression

relative dating: method of determining the age of fossils that involves comparing the rock layers in which the fossils were formed

renewable resource: natural resource that is replaced by nature

replication: process in which DNA molecules form exact duplicates

reproduction: process by which living things give rise to the same type of living thing

reproductive adaptation: difference in the mechanism of the reproductive cycle of a species, that improves the probability of its survival under the conditions of its environment

reproductive system: body system in which the male and female sex cells are produced and which enables an organism to produce offspring

respiration: any of various energy-yielding oxidative reactions in living matter that typically involve transfer of oxygen and production of carbon dioxide and water; process by which living organisms perform a catabolic exchange of oxygen and carbon dioxide and oxidize nutrient molecules for energy production

respiratory system: body system that gets oxygen into the body and removes carbon dioxide and water from the body

response: some action or movement of an organism brought on by a stimlilus

retina: inner eye layer on which an image is focused

rheumatic fever: an illness, predominantly affecting children and following a streptococcus infection (eg, strep throat) or scarlet fever, which can cause long-lasting effects in the skin, joints, heart, and brain and may be followed by Sydenham’s chorea, obsessive-compulsive disorder or a tic disorder.  Symptoms) fever, joint pain, nausea, stomach cramps, and vomiting.  Treatment) prophylactic antibiotics

rheumatology: internal medicine} study of the immune system; non-surgical evaluation and treatment of the rheumatic diseases and conditions, ie, immune system abnormalities or musculoskeletal system related symptoms. Ref: American College of Rheumatology

rhizoid: thread-like, root-like, unicellular or multicellular absorbing structure, found in fern gametophytes and in some non-vascular plants such as mosses for the absorption of water and nutrients

rhizome: underground stem of a fern

ribosome: a protein-making site of a cell; a roughly spherical grain-like structure made up of RNA and attached to the inner surface of an endoplasmic reticula (passageway) in the cytoplasm of cells

RNA (ribonucleic acid): nucleic acid in the nucleus and cytoplasm of cells that "reads" the genetic information carried by DNA and guides protein synthesis, ie, translates the genetic code of DNA into proteins. Its structure is similar to DNA. Example classes) messenger-, transfer- and ribosomal-RNA.

root hair: microscopic extension of an individual cell that greatly increases the root's surface area and helps the plant absorb water and minerals from the soil

rough endoplasmic reticulum: an organelle with a large number of ribosomes attached, found in eukaryotic cells and is important in making proteins and in preparing cell secretions

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sac fungus: fungus that produces spores in a saclike structure

salmonella: a genus of rod-shaped, Gram-negative bacteria that are a common cause of food poisoning

saprophyte: vegetative organism that obtains nutrients from dead organisms or decaying orgainic matter

sarcodine: protozoan that moves by means of pseudopods

savanna: grassland

scavenger: organism that feeds on dead animals

science: creation, verification and testing of hypotheses, theories, models, laws, or principles that help to approximate, explain, simplify, utilize and predict commonly accepted and repeatable observations and data about the material universe or physical reality. The organized body of knowledge about the material universe which can be currently verified or tested or which is currently under verification and testing; a particular branch of either such a process of study, or such a body of knowledge, eg, astronomy, biology, chemistry, geology, and physics.

scientific method: systematic approach to problem solving, testing, creation, verification or disproving assumed or derived postulates, theorems, or laws; generally verifiable by repeatable independent tests and observations

scrapie: disease of sheep caused by a prion that can withstand boiling, x-ray irradiation, and treatment with formalin; incubation period is longer than 4 months

scrotum: external sac in males that contains the testes

seaweed: large photosynthetic protist that is not a true plant
Examples) rhodophytes and kelps

secondary metabolism metabolic process producing a metabolite, which peaks only after the main growth phase of the cell is completed

secrete: discharge or release of a liquid by organs, tissues, or by a cell

sedimentary rock: type of rock formed from layers of mud and sand that harden slowly over time

seed [OE. sed, fr. sawan to sow; akin to D. zaad seed, G. saat]: structure from which a new plant grows; a ripened ovule consisting of an embryo of a plant (which through germination, may produce a new plant) stored food, and one or more integuments, or coverings (a seed coat),
Technical) has an outer and an inner coat, and within these the kernel or nucleus. The kernel is either the embryo alone, or the embryo inclosed in the albumen, which is the material for the nourishment of the developing embryo. The scar on a seed, left where the stem parted from it, is called the hilum, and the closed orifice of the ovule, the micropyle.

selective breeding: crossing of animals or plants that have desirable characteristics to produce offspring with desirable characteristics

self-pollination: process in which a plant pollinates itself

semicircular canal: curved tube in the inner ear that is responsible for balance

semiconductor: poorly conducting substance that contains a full band and an empty band, with small energy gaps between the bands

sensory cell: [Latin sensorius=>sensus=>faculty of perceiving] specialized cell for sensation  Examples) cutaneous mechanoreceptors and muscle receptors

sensory neuron: type of neuron that receives input from special receptors called sensory cells and carries these messages to the central nervous system

sepal: leaflike structure enclosing a flower when it is still a bud

septum (Pl. pl. septa): dividing wall between adjacent cells of a hypha or spore; thick wall of tissue that separates the heart into right and left sides

sessile: living attached to another object

seta (Pl. setae): a bristle or stiff hair; bristle on the segment of an earthworm that helps it pull itself along the ground

sex chromosome: chromosome that determines the sex of an organism

sex-linked trait: characteristic passed from parent to child on a sex chromosome

sexual reproduction: process where two gametes fuse to form one hybrid, fertilized cell with a new genome different from either parent; reproduction usually requiring two parents

sickle-cell anemia: inherited blood disease that causes red blood cells to become sickle shaped

siliceous: containing silica

skeletal muscle: muscle that is attached to bone and moves the skeleton

skin: outer covering of the body

slime mold: nonphototrophic eukaryotic microorganism lacking cell walls, which aggregate to form fruiting structures (cellular slime molds) or simply bloblike masses of protoplasm (acellular slime molds). It resembles a protozoan and a fungus during the two stages of its life cycle

small intestine: organ in the digestive system in which most digestion takes place

smog: thick cloud of pollutants

smooth muscle: muscle responsible for involuntary movement

smut disease caused by a member of the Ustilaginales (Ustomycetes) group of fungi; also the common name for a species in this group

solar energy: energy from the sun

somatic cell: cell that has a diploid number of chromosomes and reproduces by mitosis; most cells in multicellular plants and animals are somatic cells; generally all the cells in the body except those directly involved with reproduction  See) sex cell.

somatostatin: harmone which inhibits the release of numerous other hormones

sorption : either or both of the processes of adsorption and absorption.

sorus (plural: sorl): spore case on the underside of a fern frond

species: last and most specific classification in the taxonomic sequence following genus and within which organisms are able to interbreed to produce young; the first word of the binomial nomenclature of an organism

sperm: male sex cell or gamete

sphygmomanometer (sfihg-moh-muh-NAHM-uh-tuhr)-instrument for measuring blood pressure

spinal cord: part of the nervous system that connects the brain with the rest of the nervous system

spindle (nucleospindle, mitotic spindle): network of fiberlike microtubules that forms in the cell nucleus during mitosis and helps move chromosomes by connecting centrosomes to kinetochores

spindle fibers: microtubules that compose the mitotic spindle within a cell nucleus

spirillum (plural: spirilia): spiral-shaped bacterium

spleen: lymphatic system blood reservoir and blood filtering organ that produces lymphocytes and destroys old blood cells

spongy layer: irregularly shaped food-making cells of the lower mesophyll of a leaf

spontaneous generation: theory that states that life can spring from nonliving matter

sporangium (Pl. sporangia): structure within which spores are formed

spore: general term for a reproductive structure in fungi, bacteria and cryptogams, commonly one-celled, but in fungi frequently a multicelled structure which is in effect a group of one-celled spores because every cell may produce one or more germ tubes.

spore wall usually a layered structure containing from the inner layer outwards, an endosporium, episporium, exosporium or epitunica, perisporium or myxosporium, and ectosporium

sporocarp any spore-bearing organ; fruit-body

spore formation

sporophore a spore-bearing or spore-supporting structure in fungi, which may be simple as in sporangiophore or complex as in ascomata and basidiomata; fruit-body

sporophyte: plant, or phase of a life cycle, that bears the spores formed during the sexual reproductive cycle  See) gametophyte

sporozoan: protozoan that has no means of movement

sporulation: the formation of spores or division into many small spores

stalk: stemlike structure in a mushroom that supports the cap

stamen: male reproductive organ of a flower  See) pistil.

stigma: structure at the top of pistil

stimulant: drug that speeds up the activities of the nervous system

stimulus (plural: stimuli): signal to which an organism reacts; change in the environment

stochastic: involving a random variable; involving chance or probability

stoma (plural: stomata): opening in the lower surface of the epidermis

stomach: J-shaped, muscular organ connected to the end of the esophagus in which foods are physically,and chemically digested

strain (clone): population of cells all descended from a single cell

stratification: division of an aquatic community into distinguishable temperature based layers.

streptococcus: (Gr. strepto=>twisted + kokkos=>berry; named from microscope observations) group of bacteria (gram-positive, facultative anaerobic cocci) that cause diseases. are ). Related diseases) strep throat, strep pneumonia, scarlet fever, rheumatic fever and heart valve damage, and glomerulonephritis.

strip cropping: farming method in which strips of cover crops are grown between strips of other crops to hold down the soil

style: slender tube that connects the ovary to the stigma

sucrose (saccharose) [=>sugar-sugar]: common table sugar or the water-soluble disaccharide produced by most plants
Uses) commonly extracted from sugarcane and sugar beets

sulfate-reducing bacterium: (Pl. ..bacteria) a bacteria which is able to reduce sulfate SO42- (as a terminal electron acceptor) using electrons donated from organic acids, fatty acids, alcohols or hydrogen (electron donors).

surfactant: natural or synthetic chemical that promotes the wetting, solubilization, and emulsification of various types of organic chemicals; a surface active agent, ie, a molecule that tends to adsorb at surfaces or interfaces; usually amphiphilic molecules with hydrophilic (water soluble) head groups and hydrophobic tails. The hydrophilic head group may be ionic or non-ionic. Surfactants generally lower the surface tension of water.

swim bladder: sac filled with air that enables bony fish to rise or sink in water

symbiosis: relationship in which an organism lives on, near, or in another organism

symptom: sign of disease

synapomorphy: a derived characteristic used to infer common ancestry because it is shared by members of a taxa under consideration

synapse: tiny gap between an axon and a dendrite

systematics: the science, usually divided into the two areas of phylogenetics and taxonomy, of naming and classifying organisms with regard to natural relationships.

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taiga: northernmost area of a coniferous forest biome

talon: sharp claw of a bird

taxon: any named group of organisms, not necessarily a clade

taxonomy: science of classification; study of the classification of organisms according to standard rules. Most modern taxonomies have phylogenetic (or natural) aspects of attempting to group organisms according to evolutionary descent (cladistic analysis attempts to do so strictly). A taxonomic sequence is defined, whereby group classifications are reduced from the most general, to the most specific similarities and from the most differences to the least differences in structure, function, behavior and genetic inheritance.
See) Kingdom, Phylum (Division), Class, Order, Family, Genus, Species   History ) One primeval system was based on harmful vs. non-harmful organisms. Aristotle's system, 4th century BC and lasting over 2,000 years, was based on whether the organism had red blood or not, then subdivided organisms by physical characteristics. Swedish naturalist Carolus Linnaeus, 18th century, developed a binomial nomenclature and classification system of characteristics, the basic framework of which is still in use today. This static taxonomy served to demonstrate the unchanging order inherent in Biblical Creation. Darwinians overturned the static view of nature by the middle of the 19th century and proposed natural selection as a mechanism of change. Following classifications attempted to reflect evolutionary types of relationships and distances between organisms. Classifications have continued to change and are ever-growing. See) systematics, phylogenetics

telophase: fourth stage of mitosis resulting in the formation of two individual cells

temperature inversion: atmospheric condition in which a layer of cool air containing pollutants is trapped near the ground under a layer of warm air

tendon: connective tissue that connects muscle to bone

terracing: farming method in which a slope is made into a series of level plots in steplike fashion to avoid erosion

territory: area where an animal lives

Tertiary: first period of the Cenozoic era (after the Mesozoic era and before the Quaternary period), spanning the time between 65 and 1.8 million years ago.

testis (plural: testes): male sex gland; endocrine gland that produces male hormones

testosterone: hormone responsible for the growth of facial and body hair, broadening of the shoulders, and deepening of the voice in males tetracycline: broad-spectrum antibiotic effective against a wide variety of bacteria including Hemophilus influenzae, Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia psittaci, Chlamydia trachomatis, Neisseria gonorrhoeae, etc.
History) chlortetracycline was the first drug of the tetracycline family, introduced in 1948 Brand Names): Achromycin, Sumycin

theory: a logical explanation of events that happen in nature.

thermal pollution: release of heat into the environment

thymine: a pyrimidine (nitrogenous base) and constituent of nucleotides and as such one member of the base pair A-T (adenine-thymine) in DNA.

thyroid: endocrine gland that produces a hormone that controls metabolism

tissue: group of cells that are similar in structure and perform a special function; second level of organization in an organism

tolerance: effect of drug abuse in which a person must take more and more of a drug each time to get the same effect

topsoil: rich upper layer of soil

total coliforms: gram-negative, aerobic or facultative anaerobic, nonspore forming rods; originally believed to indicate the presence of fecal contamination, but are widely distributed in nature and not always associated with the gastrointestinal tract of warm blooded animals; still widely used as an indicator for potable water in the U.S.

toxic:: poisonous

toxin: poison

trachea: windpipe; carries air to lungs

trait: attribute or characteristic within a species for which heritable differences can be defined

transduction: transfer of genetic determinants from one microorganism to another by a viral agent

transformation: In microbiology) genetic transfer wherein DNA from a donor cell enters a recipient cell and is incorporated into the recipient DNA by genetic recombination.

transfusion: process of transferring blood from one body to another

transpiration: process for regulating water loss through the leaves of a plant

transposon: segment of DNA with a repeat of an insertion sequence element at each end and which can migrate from one plasmid to another within the same bacterium, to a bacterial chromosome, or to a bacteriophage

triglyceride (triacylglycerol, neutral fat): lipid consisting of three fatty acids bound to glycerol; excess triglycerides are removed from the blood by insulin  Uses) high triglyceride counts in the blood is an indicator of diabetes and increased risk of heart disease (normal < 200 mg/dl)  Prevention) exercise, a low-fat diet, weight loss

trilobite [=>usually three lobed]: any of numerous species of extinct (by the close of the Paleozoic era) hard-shelled, segmented arthropods common in the Silurian and Devonian periods and belonging to the order Trilobita. A signature creature of the Paleozoic Era, Trilobites existed over 300 million years ago in the ancient seas and were extinct before dinosaurs existed. The highest diversity occured during the Cambrian Period, slowly diminishing through the Paleozoic until their extinction in the Middle Permian, a longevity of some 280 million years. All trilobite fossils are covered by a hard outer shell containing calcium carbonate and chitin, and are composed of the three main body parts: a cephalon (head), a segmented (from 2 to more than 40 segments) thorax, and a pygidium (tail piece). The name "trilobite," however, refers to the longitudinally symmetric right and left pleural lobes flanking a central or axial lobe. These three lobes run from the cephalon to the pygidium. The trilobites have pairs of legs under each body segment. The extremities also have a fringed appendage probably with gill and swimming functions. Like all arthropods, throughout their life, trilobites periodically moulted in order to grow. In this way a single trilobite could produce many individual fossils. Entire trilobites are uncommon because the skeleton breaks apart while moulting. Legs, antennae and other soft parts are rarely preserved. There are eight orders of classification: Agnostida, Redlichiida, Corynexochida, Lichida, Phacopida, Proetida, Asaphida and Ptychopariida.

triploid: having or being a chromosome number three times the haploid number

tropical rain forest: forest biome that receives at least 200 centimeters (79 inches) of rain yearly

tropism: movement of a plant toward or away from a stimulus

tuber: underground stem of a plant

tuberculosis: (TB, antiquated: consumption) highly infectious, potentially fatal disease of humans and animals caused by Mycobacterium tuberculosis causing hard nodules (tubercules) and crusty dead spots in lung and bone tissue.
Symptoms) bad cough, wasting debility. Now a common secondary infection accompanying AIDS, wherby antibiotic-resistant strains have developed with the potential for major epidemics.

tumor: swelling of tissue that develops separately from the tissue surrounding it

tundra: biome that rims the Arctic Ocean around the North Pole and has a cold, dry climate

typhoid fever: acute illness with fever caused by infection with the Salmonella Typhi bacteria contracted from contaminated water and food.  Symptoms) fever, headache, constipation, malaise, chills, and myalgia (muscle pain). Diarrhea is uncommon, and vomiting is not usually severe. Confusion, delirium, intestinal perforation, and death may occur in severe cases. Without therapy, the illness may last for 3 to 4 weeks and death rates range between 12% and 30%. A chronic carrier state (excretion of the organism for more than 1 year) occurs in approximately 5% of cases.  Treatment)F antibiotics; not preventative.

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umbilical cord: structure that connects an embryo to its mother and transports food, oxygen, and wastes

unicellular: one celled


urea: nitrogenous waste formed in the kidney; normally cleared from the blood into the urine by the kidney.
Symptoms) diseases that compromise the function of the kidney often lead to increased blood levels of urea as indicated by a blood urea nitrogen (BUN) test.

ureter: tube that conducts urine to the urinary bladder

urethra: tube through which urine passes out of the body

uracil: a pyrimidine (nitrogenous base) and constituent of nucleotides and as such one member of the base pair A-U (adenine-uracil). It is normally found in RNA but not DNA.

urinary bladder: sac of tissue that stores urine

uterus: pear-shaped structure in which the early development of a baby takes place


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vaccine: substance that increases immunity

vacuole: large, round sac in the cytoplasm of a cell that stores water, food, enzymes, and other materials

valve: small flap of tissue between the upper and lower chambers of the heart

variable: factor being tested in an experiment or a factor that is allowed to vary while other factors are held or assumed constant

variation: difference in members of the same species

vascular: relating to the blood vessels (composed of arteries, veins and capillaries) of the body; as a group, referred to as the vascular system

vascular plant: plant that contains transporting tubes that carry water and nutrients throughout the plant body; referring to the xylem and phloem tissues

vein: blood vessel that carries blood to the heart  See) artery.

venom: poison produced in special glands by snakes

ventricle: lower chamber of the heart

vertebra (plural: vertebrae): bone that makes up a vertebrate's backbone

Vertebrata [division of the Animal kingdom]: animals with a backbone composed of bony or cartilaginous vertebrae, together with Amphioxus in which the backbone is represented by a simple undivided notochord. The Vertebrata always have a dorsal, or neural, cavity above the notochord or backbone, and a ventral, or visceral, cavity below it.
Taxonomy ) subdivisions (classes): Mammalia, Aves, Reptilia, Amphibia, Pisces, Marsipobranchia, and Leptocardia

vertebrate: animal with a vertebrae (backbone, spine)
Taxonomy ) within phylum Chordata and subphylum Vertebrata

villus (Pl. villi): hairlike projection in the small intestine through which food is absorbed into the bloodstream

virus: infectious noncellular agents containing hereditary material (a genome) that only reproduces within a host (infected) cell by directing that cell's nucleic acids to synthesize viral nucleic acids and proteins. It consists of highly organized sequences of nucleic acids (either DNA or RNA, depending on the virus) covered by protein; some animal viruses are also surrounded by a membrane. Viruses straddle the definition of life, lying between supra molecular complex and a very simple biological entity. Viruses are missing most of the structures and activities common to organisms, including reproductive biosynthetic machinery. In general, it is a single strand of genetic information encased within a protein capsule. A virus must infect a suitable host cell to replicate itself. Viruses exist in two distinct states. When not in contact with a host cell it is in essence a static non-living organic particle called a virion. When the virion comes into contact with an appropriate host, it becomes active and is again referred to as a virus. It then displays properties typified by living organisms, such as reacting to its environment and directing its efforts toward self-replication.

virion: A "non-living," dormant stage of a virus when not in contact with a host cell. During this stage, which may last extended periods of time, there are no internal biological activities and it is in essence a static organic particle. When a virion comes into contact with an appropriate host, it becomes active and is again referred to as a virus. It then displays some of properties typified by living organisms, such as reacting to its environment. In the viral state it directs a host cell to replicate the virus, since it lacks "complete" reproductive capacity.

vitamin: nutrient that helps regulate growth and normal body functioning

vocal cord: tissue in the larynx that vibrates with the passage of air to form sounds

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warmblooded: having a constant body temperature

warmwater fish: prefer water temperatures ranging between 18-29 ºC (65-85 ºF). Examples) smallmouth bass, largemouth bass, and bluegill.  See) coldwater- and coolwater fish

waterborne disease ("borne" implies carried by, not born in): diseases associated with transmission through water by pathogenic organisms. Examples-bacteria) cholera, bacillary dysentery, shigellosis, and typhoid fever. Examples-viral, protozoa, helminths) Hepatitis A (virus); Cholera (bacteria); Poliomyelitis, (virus); Diarrheas (bacteria-Escherischia Coli, salmonellas, and Yersinia Enterocolitica); Viral gastroenteritis (virus); Bacillary dysentery (bacteria-various species of shigellas); Campylobacter dysentery (bacteria); Amoebic dysentery (protozoa); Giardia lambliasis (protozoa); Balantidiasis (protozoa); Helminthiasis caused by Ascaris and Trichuris (helminths) History) During the London cholera epidemics of 1853-1854, Dr. John Snow conducted experiments in epidemiology and found that nearly everyone who became ill obtained their drinking water from a specific well into which a cesspool was leaking. Those who became ill either drank water from the well or came into contact with fecally contaminated material while tending the sick.

watershed: land area in which surface runoff drains into a river or system of rivers and streams

water table: upper level of a water-saturated zone in a ground water aquuifer where the soil and all openings in the rocks are saturated; irregular surface of contact between the zone of saturation and the zone of aeration; that surface in unconfined groundwater at which the pressure is equal to that of the atmosphere

weight: measure of the force of attraction between objects due to gravity

white blood cell: blood cell that acts as a defense system against disease

wild strain: strain (eg, vial) found naturally, as opposed to one created in the laboratory

wild type: naturally-occuring, normal, non-mutated version of a gene; original parent strain of a laboratory test organism; referring to how organisms are found naturally, in the wild, before mutations were induced by researchers

windbreak: row of trees planted between fields of crops to prevent erosion due to wind

withdrawal: effect of drug abuse that occurs when a person who is physically dependent on a drug is taken off that drug

woody stem: rigid plant stem

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xylem: tubelike plant tissue that carries water and soluble minerals throughout the body of vascular plants

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zoology: study of animals

zooplankton: plankton that are not photosynthetic to include minute animals and nonphotosynthetic protists

zygote: fertilized egg


An Agricultural and Environmental Biotechnology Annotated Dictionary

  • Public Perception Issues in Biotechnology , Susan Allender-Hagedorn and Charles Hagedorn
  • Virginia Polytechnic Institute & State U

    Aquatic, Wetland and Invasive Plant Glossary:   Center for Aquatic and Invasive Plants with Links, Dave L. Sutton, Ph.D, U Florida

    Biological Basis of Heredity - Glossary of Terms: Palomar College

    Chemistry Dictionary,   Chemical Inst of Canada, Hammilton

    Classification of Living Things:   Glossary of Terms

    Cumulative Glossary for Vascular Plants, Flora of Australia:   Australian Botany pages knowledge base, compilation of public domain documents & contributions
    Fungi of Australia Glossary:   Australian Biological Resources Study, Australian Botany pages

    A Hypermedia Glossary of Genetic Terms by Birgid Schlindwein

    Hypertext Guide to Terms in Colloid and Polymer Science, Adrian R. Rennie, Dept Chemistry, King's College London

    Illustrated Glossary of Plant Pathology   APSnet, The American Phytopathological Society

    Life Science Glossary, Prentice Hall, Life Science 1988, Jill Wright, Charles R. Coble, Jean Hopkins, Susan Johnson, David LaHart

    Life Science Dictionary, BioTech Resources and Indiana U: U Texas web site - MedTerms Medical Dictionary Index

    On-Line Biology Book - Glossary:  Biology, Estrella Mountain Community College

    Natural and Accelerated Bioremediation Research, Appendix B: Glossary:   Office of Science, US DOE

    Paleontology at the U.S. Geological Survey - Glossary of Terms, Geologic in the Eastern Region, USGS

    Pest Management Glossary, David Dent & Rosy Allcott

    PharmInfoNet Polymer Chemistry Glossary:   Polymer Discovery, Key Centre for Polymer Colloids, U Sydney

    Selected Terms in Colloid and Interface Science, Dr. Laurier L. Schramm

    the smallest page on the web:   Intro to Microscopy, Microscopy-UK

    The Tree of Life - Root, Popular Groups, Search Taxon name: U Arizona

    UCMP Glossary of biological terms:   Museum of Paleontolgy UC, Berkeley

    Water related health risks:   Learn more about water, MSF-Visit a REgugee Camp

    Water Resources of Georgia-USGS Chat microbial: Glossary of water terms:  

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