A

abiotic factor: nonliving things in an environment

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

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: change that increases an organism's chances of survival under the conditions of its environment. Types of adaptation are morphological (structural), physiological (cell and tissue - chemical and physical activity) or reproductive.

adrenal: endocrine gland on top of each kidney that produces the liot-mone adrenaline

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 )

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

alga (Al.-guh; plural: algae): nonvascular unicellular or multicellular aquatic plant that contains chlorophyll and grows in both fresh water and seawater. Some algae may be used as a food source, some as thickeners or in pigments such as beta carotene. They are used as oxygen producers for aerobic bacteria digesters in sewage treatment. Some cause fouling in pools and reservoirs, or clogging in pipes.

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: each member of a gene pair

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

alveolus (plural: alveoli): grapelike cluster of tiny balk)ons in the lungs

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 .

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

amoeba: sarcodine, a type of protozoan, that lives in fresh water and moves by means of 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

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

angiosperm: type of seed plant whose seeds are covered by a protective wall

annual ring: one year's growth of xylem cells

antibiotic: chemical that destroys or weakens diseasecausing bacteria

antibody: protein produced by certain kinds of white blood cells in response to an invasion by a particular organism or substance

antigen: invading organism or substance

aorta: largest blood vessel In the body

artery: blood vessel that carries oxygenized blood away from the heart ( see vein ).

arthropod: invertebrate that has jointed legs and an exoskeleton

asexual reproduction: reproduction requiring only one parent

atherosclerosis (ath-uhr-oh-skluh-ROH-sihs): 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

atrium (plural: atria): upper heart chamber

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

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

axon: fiber that carries messages away from a body cell

B

bacillus (plural: bacilli): rod-shaped bacterium

bacteriophage: virus that infects bacteria

bacterium (plural: 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.

benign: harmless

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.

bile: substance produced by the liver that aids in digestion

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

biogenetic law (or 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: division of area with similar climate, plants, and animals

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

biotic factor: living things in an environment

botany: study of plants

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

C

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

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 formed by tal) trees in the forest

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

capillary: tiny, thin-walled blood vessel

capsule: cup-shaped part of the nephron

carbohydrate: energy-rich substance found in foods such as vegetables, cereal grains, and breads

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

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 of structure and function of a living thing

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

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

cerebellum: part of the brain that controls balance and posture

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

chemical digestion: breaking down of food by enzymes

chlorophyll: green Aibstance, 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

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

chordate: phylum of vertebrates

chromatin: threadlike coils of chromosomes

chromosome: rod-shaped cell that directs the activities of a cell and passes cell traits to new cells

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

chronic disorder: lingering, or lasting, illness

cilium (plural: cilia): small, hairlike projection on the outside of a ciliate that acts like a tiny oar and helps the organism move

ciliate: protozoan that moves by means of 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

class: classification grouping between phylum and order

classification: grouping of living things according to similar characteristics

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

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

coccus (plural: cocci): sphere-shaped bacterium

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

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

colloid (colloidal): microscopic dispersion of particles suspended in a fluid medium.

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: symbiotic relationship in which only one partner in the relationship benefits

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

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

cornea: transparent protective covering of the eye

cotyledon: leaflike structure of a young plant that stores food

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

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

cytoplasm [Latin plasmator: maker, plasmo: to mould] all the protoplasm, or living material, outside the nucleus of a cell

D

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

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

dermis: inner layer of the skin

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

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

diatom: type of golden algae that is made of a tough grasslike material

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: type of fire algae that has two flagella

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.

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 that stores the information needed to build proteins and carries genetic information about an organism

dominant: stronger trait in genetics

E

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.

endocrine:

endocrine gland: A gland that secretes its products directly into the bloodstream. ( see exocrine gland ).

endoplasm:

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

epidermis:

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 cell, eucaryotic cell) cell or organism with a membrane-bound, structurally discrete nucleus and other well-developed subcellular compartments. Eukaryotes include all organisms except viruses, bacteria, and cyanobacteria (blue-green algae). ( see prokaryote)

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

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

eyespot: reddish structure in Euglena that is sensitive to light

F

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

family: classification grouping between order and genus

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

feces: solid waste that is eliminated from the body

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 process in which sugars and starches are changed into alcohol and carbon dioxide; process by which yeasts obtain their energy

fern:

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 (plural: flagella): long, thin whiplike structure that propels an organism

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

fossil: imprint or remains of plants or animals that existed in the past

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

fruit: ripened ovary of an angiosperm

fruiting body: spore-containing structure in a fungus

fungus (plural: fungi): nonvascular-plantlike organism that has no chlorophyll

G

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

gene ordered sequence of nucleotides located in a particular position on a particular chromosome that encodes a specific functional molecule or unit within an organism. It is the fundamental unit of heredity.

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 genes, or parts of DNA, are transferred from one organism into another organism

genetics: study of heredity

genotype :JEE-nuh-tighp): genetic makeup of an organism

genus (plural: genera): group of organisms that are closely related; classification group between family and species

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

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

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.

gradualism: belief that evolution is a slow and steady process

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

gravity: force of attraction between objects

groundwater: underground water

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

H

habitat: place in which an organism lives

half-life: time it takes for half of a radioactive element to decay

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

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

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

hemoglobin: it-oti-containing protein in red blood cells

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: passing a particular trait or characteristic from a forebears to progeny; sum of an organism's inherited genetic traits.

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

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

homeostasis: ability of an organism to keep conditions inside its body the same even though conditions in its external environment change

homologous: similar in structure

hormone: chemical messenger that travels through 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: 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.

hypertension: high blood pressure

hypha (plural: hyphae: (HlGH-fee): 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.

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

hypothesis: suggested solution to a problem

I

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: body's response to an attack by disease-causing organisms

ingestion: taking in food; eating

inhale: breathe in

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

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

interneuron: type of neuron that cotitiects sensory and motor neurons

interphase: period between one mitosis and the next

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

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J

joint: place where two bones meet

K

kidney: major excretory organ

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

kingdom: largest classification grouping

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L

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

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

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

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

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

litter: material that is disposed of in improper places

liver: organ that produces bile and urea

livenvort: small, green nonvascular plant with flat leaflike parts

lung: main respiratory organ

lymph: plasma that leaks out of the blood and surrounds and bathes body cells

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

M

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

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

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

meiosis (migh-TOH-sihs): process that results in cells with only half the normal number of chromosomes

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 (mehn-STRAY-shuhn): process in which the blood and tissue from the thickened lining of the uterus pass out of a female's body through the vagina

mesophyll:

metabolism: all chemical activities in an organism

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

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

microbiology: study of microorganisms

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.

micronucleus (pl. micronuclei) Definition: microorganism: microscopic organisms

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

mitochondrion (plural: mitochondria): rod-shaped structure that is referred to as the powerhouse of a cell

mitosis [Latin mitis: mild, gentle; ripe, mature] duplication and division of the nucleus and of the chromosomes during cell reproduction

molar: back tooth that grinds arid crushes food

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

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

molt: periodically shed one's skin

Monera: (prokaryotes, monerans) biological kingdom composed of bacteria 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).

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

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 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

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

mutualism: symbiotic relationship that is helpful to both organisms

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: gram-positive bacterium that causing tuberculosis

N

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

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: nerve cell

neutron: neutral particle in the nucleus of an atom

niche: role of an organism in its community or environment

nitrogen base: substance in DNA that contains the element nitrogen

nitrogen fixation: process by which some kinds of bacteria take nitrogen directly from the air and form nitrogen compounds

nitrogenous base: nitrogen-containing molecule having the chemical properties of a base

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

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: large organic compound that stores information that helps the body make the proteins it needs

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

nucleotide: subunit of a DNA or RNA molecule. It consists of a nitrogenous base (adenine, guanine, thymine, or cytosine in DNA; adenine, guanine, uracil, or cytosine in RNA), a phosphate molecule, and a sugar molecule (deoxyribose in DNA and ribose in RNA). Thousands of nucleotides are linked to form a DNA or RNA molecule.

nucleus: (Pl: nuclei) cell structure that directs all the activities of the cell. Cellular organelle in eukaryotes that contains the genetic material.

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.

O

oil: energy-rich substance

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

opiate: pain-killing drug produced from the opium poppy

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

order: classification grouping between class and family

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

organelle: tiny cell structure organism: entire living thing that carries out all the basic life functions; membrane-bound body found in the cytoplasm of the cell that performs specific cellular functions.

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

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: hollow structure that contains the egg cells of a flower; female sex gland; endocrine gland that produces female hormones

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: structure that contains the female sex cells of a seed plant

P

pacemaker: special tissue in the heart that controls  the pace at which the heart beats

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

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

pancreas (PAN-kree-uhs): organ that produces 'Pancreatic juice and insulin

paramecium (plural: paramecia): type of protozoan that moves by means of cilia

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

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

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:

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

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

permafrost: permanently frozen tundra soil

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 (for which the letters "pH" represent).

phenotype: visible characteristic of an organism

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

phloem: tubelike plant tissue that carries food down the plant

photosynthesis: process by which organisms use energy from sunlight (or articial light) to make their own food, whereby water and carbon dioxide are converted to carbohydrate and oxygen in the presence of chlorophyll. This occurs in plants, algae, cyanobacteria and lichens.

phylogeny (phylogenesis, phylogenetic, phylogenic): evolutionary history of a particular taxonomic group, usually of a species.

phylum (plural: phyla): second largest classification grouping of the taxonomic sequence of kingdom, phylum,

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

phytoplankton: microscopic plants that live on the surface of the ocean

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 organisms that float or swim near the surface of water

plasma: the fluid portion of blood or whole blood minus the cells, yellowish in color.

plasmid: bacterial DNA in the form of a rilig

platelet: blood cell fragment that aids in blood clotting

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. A multitude of polymers are organically synthethized for industry and research.

polypeptide (protein): a polymer composed of multiple amino acid units linked by peptide bonds.

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

portifera:

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

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

prokaryote: (procaryote, prokaryotic cell, procaryotic cell) cell or organism lacking a membrane-bound, structurally discrete nucleus and other subcellular compartments. Bacteria are prokaryotes (see eukaryote, chromosomes).

producer: organism that can make its own food

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.

Protista kingdom:

proton: positively charged particle in the nucleus of an atom

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

protozoan: member of the Protista kingdom; unicellular, animal-like organism with a nucleus

pseudopod: extension of the cytoplasm of a sarcodine that is used in moving and getting food

psychological dependence: emotional need for a drug

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

puberty (pyoo-buhr-tee): beginning of adolescence

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

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

R

radioactive:

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

recapitulation theory (or biogenetic law): 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.

receptor: part of the nervous system that responds to stimuli

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

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

respiration: process by which living organisms take in oxygen and use it to produce energy

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 (REHT-uhn-uh): inner eye layer on which an image is focused

rhizoid: rootlike structure through which mosses absorb water

rhizome: underground stem of a fern

ribosome: grainlike body made up of RNA and attached to the inner surface of an endoplasmic passageway; a protein-making site of the cell

RNA (ribonucleic acid): nucleic acid that "reads" the genetic information carried by DNA and guides the protein-making process

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

S

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: organism that feeds on dead organisms

sarcodine: protozoan that moves by means of pseudopods

savanna: grassland

scavenger: organism that feeds on dead animals

scientific method: systematic approach to problem solving

scrotum: external sac in males that contains the testes

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: structure from which a plant grows; contains a young plant, stored food, and a seed coat

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

sensory neuron: type of neuron that carries messages from special receptors to the central nervous system

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

septum: thick wall of tissue that separates the heart into right and left sides

seta (plural: setae): 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: reproduction usually requiring two parents

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

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

skin: outer covering of the body

slime mold: bloblike organism resembling 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

solar energy: energy from the sun

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

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

species: group of organisms that are able to interbreed and produce young

sperm: male sex cell

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

spirillum (plural: spirilia): spiral-shaped bacterium

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

spore: tiny reproductive cell

sporozoan: protozoan that has no means of movement

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

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

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

sulfate-reducing bacterium: (Pl. ..bacteria) a bacteria which is able to reduce sulfate SO₄^2- (as a terminal electron acceptor) using electrons donated from organic acids, fatty acids, alcohols or hydrogen (electron donors).

Author: Mirrored from Tsute Chen's Glossary of Microbiology Definition: surfactant: 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

synapse: tiny gap between an axon and a dendrite

T

taiga: northernmost area of a coniferous forest biome

talon: sharp claw of a bird

taxonomy: science of classification

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

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

thermal pollution: release of heat into the environment

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

toxic:: poisonous

toxin: poison

trachea: windpipe; carries air to lungs

trait: a characteristic of an organism

transfusion: process of transferring blood from one body to another

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

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 causing hard nodules (tubercules) and crusty dead spots in lung and bone tissue. It is caused by Mycobacterium tuberculosis. Symptoms include a bad cough and wasting debility. Now a common secondary infection accompanying AIDS, wherby antibiotic-resistant strains have developed which have tge potential to cause 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 include: 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: antibiotics; not preventative.

U

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

unicellular: one celled

univalve:

urea: nitrogen waste formed in the liver

ureter: tube that conducts urine to the urinary bladder

urethra: tube through which urine passes out of the body

urinary bladder: sac of tissue that stores urine

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

V

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 plant: plant that contains transporting tubes that carry materials throughout the plant

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

vertebrate: animal with a backbone

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

virus: tiny particle that contains hereditary material

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

w

warmblooded: having a constant body temperature

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

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

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

x

xylem: tubelike plant tissue that carries water and minerals through the plant

z

zoology: study of animals

zygote: fertilized egg

An Agricultural and Environmental Biotechnology Annotated Dictionary, Susan Allender-Hagedorn and Charles Hagedorn

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

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:   MedicineNet.com

Pest Management Glossary, David Dent & Rosy Allcott

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

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