*Biology Vocabulary

Modified 2004-05

    This page has a list of vocabulary terms which you will be responsible for knowing. As we go through the semester or next few weeks, we will continue to learn a few terms at a time. You may take the test at any time you feel you are ready. Note: There are several terms which are highlighted, these terms have pages linked to the terms to help give you a better understanding of the term. If you have any questions, just give me a yell.

Biological Prefixes & Suffixes- This guide to biological terminology has prefixes and suffixes which are parts to many biological terms. This glossary was designed to acquaint you with th emore common components of such words. Each is followed by its definition and an example.

acetylcholine-neurotransmitter that stimulates skeletal muscles.

acid- 1st Sem any substance that increases the concentration of hydrogen ions when added to a water solution. This is represented on the pH scale from 0-7.
acoelomate-an animal that lacks a coelom, or body cavity.

active transport-movement of a particle through a membrane against a concentration gradient with the use of energy from ATP.

adaptation- 1st sem process of becoming adapted to an environment; an anatomical structure, physiological process, or behavioral trait that improves an organism's likelihood of survival and reproduction.

adrenaline-peptide hormone released by the adrenal medulla in times of stress; also called epinephrine.

adventitious roots-roots that grow the aboveground parts of a plant, such as stems and leaves.

aerobic- 1st sem term for processes that require oxygen or organisms which must live in an oxygenated environment.

aggregation-a temporary collection of cells that come together for a period of time and then separate.

allele-an alternative form of a gene.

allosteric enzyme-an enzyme whose shape can be altered by the binding of a signal molecule to its surface.

alveolus-microscopic air sac in the lung where oxygen and carbon dioxide are exchanged.

amino acid-organic molecule that is the building block of protein.

amnion- a membrane inside an egg enclosing the embroy.

amniotic egg-a water tight, fluid-filled egg  in birds, reptiles, and mammals.

amylase-enzyme the breaks down starches into sugars.

anaerobic-1st sem term for process not requiring oxygen or organisms which cannot live in the presence of oxygen.

anaphase-stage if cell division in which chromosome copies separate.

annual plant-plant the completes its life cycle during one growing season.

anterior-front end of bilaterally symmetric(two sides which mirror each other) animal. For us this is our stomach or front surface for 4 legged animals like dogs, it would be their heads.

antibiotic-substance used as a drug to kill bacteria.

antibody-defensive protein released by B cells in response to a foreign substance in the body. These are produced by the body and are generally all natural.

aorta- main artery in the body; receives blood from the left ventricle.

appendicular-bones that form the arms and legs.

artery-vessels that carries blood away from the heart to the body's organs.

atom-1st sem smallest unit of matter that cannot be broken down by chemical means.
This contains a nucleus, with protons and neutrons having electrons revolving around it.
ATP-synthetase-protein channel in a membrane through which protons are pumped to produce ATP.

autonomic nervous system-the network of motor nerves that regulate cardic muscle, smooth muscle, and gland activity.

autotroph-organism the obtains energy from sunlight or chemicals by producing its own food sources.

axial skeleton-bones that form the main body axis.

axon-the elongated extension of a neuron that carries impulses away from the cell body.

bacillus-rod-shaped bacteria cell.

base- 1st Sem any substance that increases the concentration of hydroxide ions when added to a water solution
biennial plant-plant that completes its life cycle within two years.

bilaterally symmetric-animal configuration with left and right halves that mirror each other.

binary fission-1st sem a form of asexual reproduction that produces identical offspring in which one cell copies itself and splits into two new cells.

binomial nomenclature-1st sem a system for giving each organism a two-word scientific name that consists of the genus followed by the species.

biology-1st sem science of life.

bronchiole- tiny air passages that connect alveoli to the bronchi.

c3 plant-plant that fixes carbon using the calvin cycle.

c4 plant-plant that fixes carbon using an alternative pathway in which the first detectable product is a four-carbon compound.

calorie-1st sem amount of energy needed to raise the temperature of 1 gram of water 1C. The calorie used to indicate the energy content of food is a calorie.

calvin cycle-the second major pathway in photosynthesis involving carbon fixation and carbohydrate formation.

cancer-a disease characterized by abnormal cell growth.

capillaries-tiny blood vessels that allow exchange between blood and cells in tissue.

carbohhydrate-1st sem organic compound composed of carbon, hydrogen, and oxygen; used by living things as an energy source. These compounds have Carbon, Hydrogen & Oxygen in a 1:2:1 ratio.

carcinogen- cancer causing substance.

carcinoma- common type of skin cancer originating in the non-pigment producing cells of the epidermis.

carnivore-1st sem Organisms which consume other heterotrophs.

catalyst-material that speeds up a chemical reaction without being used itself.

cell- smallest unit that can perform all the life processes.

cell specialization-1st sem ability of different cells to perform specific functions in a multicellular organism, such as protection, mobility and reproduction.

cell theory-1st sem principle that states all organisms are made of one or more cells that are derived from other cells, that the cell is the is the basic unit of structure and function.

cellular respiration-1st sem process by which living things obtain energy from the bonds of food molecules by breaking them apart.

cellulose- carbohydrate that is the main structural component of the cell walls of plants.

central nervous system- system composed of the brain and spinal cord.

cerebellum- region of the brain that controls coordination and balance.

cerebrum- rounded wrinkled anterior portion of the brain; center for memory, learning, emotions, and other highly complex function.

chemiosmosis- process by which cells pump protons across a plasma membrane and use the resulting proton gradient to produce ATP.

chemosynthesis-1st sem production of organic compounds using energy contained in inorganic molecules.

chloroflurocarbon- any of a group of compounds that contain carbon, chlorine, and florine, often used as coolants, propellants, or foaming agents.

chlorophyll- the green pigment molecule responsible for trapping light energy in photosynthesis.

chromosome- cellular structure on which genes are located .

chrysalis- in insect, protective capsule enclosing the transforming larva.

chyme- semisolid material in the stomach and duodenum composed of food, HCL and enzymes.

cirrhosis- degenerative condition of the liver in which cells are replaced with scar tissue and the organ shrinks into a hard mass.

closed circulatory system- system in which the blood does not leave the blood vessels and materials pass in and out by diffusing across the walls  of the vessels.

coccus- spherical-shaped bacterial cell.

coelom- fluid-filled cavity that forms within the mesoderm.

colon-organ that compacts waste for excretion; also called the large intestine.

community- 1st Sem the many different species that live together in a habitat.

compound-substance that is made up of more than one kind of atom

conjugation- temporary union of two protists to exchange nuclear material.

control- factor that is held constant throughout an experiment to test a hypothesis.

convergent evolution-process by which unrelated species become similar as they adapt to similar environments.

cranium- portion of the skull that encases the brain.

cytosol- liquid portion of the cytoplasm.


deciduous- describes trees, shrubs, and woody vines that drop all of their leaves at the end of each growing season.
dendrite- cytoplasmic extension from the body of a neuron.

deoxyribonucleic acid- also know as DNA is a nucleic acid which stores the genetic information controlling our heredity and characteristics.

dermis- thick layer of skin beneath the epidermis.

diaphragm- in mammals, sheet of muscle at the bottom of the rib cage that aids in respiration.

diastolic pressure- the low blood pressure that occurs during relaxation of the heart.

diffusion-1st sem movement of particles from an area of high concentration to an area of low concentration.

dihybrid cross- a cross that involves two pairs of contrasting traits.

diploid-1st sem term used to indicate cell containing two homologues of each chromosome.

diurnal- term describing animals that are active during the day and sleep at night.

dominant trait- trait that is expressed when its allele is homozygous or heterozygous.

dormancy- condition in which a seed or plant remains inactive for a period of time.

dorsal- top surface of a bilaterally symmetrical animal.

duodenum- first part of the small intestine.


ecdysis- process of shedding and discarding the exoskeleton; also called molting.
ecology- the study of the interactions of living organisms with one another and with their environment.

ecosystem-ecological system encompassing a community and all the physical aspects of its habitat.

ectoparasites- parasites that live outside their host.

electron- elementary particle with negative electric charge.

element- substance composed of a single type of atom.

emulsification-1st sem process in which fat globules are broken down into droplets and exposed to enzymes.

endocytosis-1st sem process by which extra cellular matter is taken up by a cell.

endoparasite- parasite that lives inside its host.

endoskeleton- an internal skeleton.

endothermic-1st sem  refers to an animal that generates its own body heat.

epithelium- protective tissue that covers the body's interior surfaces.

erythrocyte- oxygen carrying red blood cell.

eukaryotic cell-1st sem complex cell that has nucleus enclosed by a membrane and usually a great number of organelles

exocytosis-1st sem releasing materials outside a cell by discharge from waste vacuoles.

exoskeleton-hard external covering of some invertebrates.


fat-1st sem class of organic compound containing carbon, hydrogen, and oxygen and used to construct membranes and to store energy.


gamete-haploid cell that participates in fertilization by fusing with another haploid cell.
gametocyte- third state of the Plasmodium life cycle; undergoes a sexual phase in the bloodstream's of infected humans.

genotype-genetic constitution of an organism as indicated by its set of alleles.

genus- taxonomic category containing similar species.

gestation period- length of time between fertilization and birth.

glycogen- polymer of glucose used for short-term energy storage.

glycolysis- biochemical pathway that breaks down glucose into pyruvate.

gram-negative- designates a bacterium that does not retain the Gram stain.

gram-postive- designates a bacterium that retains the Gram stain.

gravitropism- growth response to gravity.

gymnosperm- seed plant that produces seeds that do not develop within a fruit.

habitat -1st sem place where an organism lives and interacts with other organisms.

half-life- the period of the time that it takes for one-half of a radioisotope to decay.

haploid -1st sem having only one set of chromosomes thus producing the gametes or sex cells.

Hardy-Weinberg principle - principle stating that the frequency of alleles in a population does not change unless evolutionary forces such as selection act on the population.

hemoglobin - component of red blood cells that blinds with and carries oxygen through the body.

hemophilia - genetic disorder that impairs the blood's ability to clot and can cause excessive bleeding.

herbivore -1st sem organism that eats only plants or algae.

heredity -1st sem transmission of genetic traits from parent to offspring.

hermaphrodite - organism that produces both eggs and sperm.

heterotroph -1st sem organism that cannot makes its own food.

heterozygous - refers to a pair of genes, or an individual, with two different alleles for a trait.

homeostasis -1st sem maintenance of the internal stability of a cell organism, or population in its environment.

homologous chromosomes - chromosomes that are similar in shape, size, and the genes they carry.

homozygous - refers to a pair of genes, or an individual, with two identical alleles for a trait.

hyperthyroidism - condition resulting from overproduction of thyroxine by the thyroid gland, characterized by nervousness, sleep disorders, irregular heartbeat, and weight loss.

hypertonic -1st sem describes a solution with a higher concentration of solute molecules than the solution across a selectively permeable membrane.

hypothesis -1st sem proposed explanation or a If-Then statement that tells what you think will happen during your experimental procedure.

hypothyroidism - condition resulting from underproduction of thyroxine by the thyroid gland, characterized in childhood by stunted growth and mental retardation and characterized in adulthood by lack of energy and weight gain.

hypotonic -1st sem describes a solution with a lower concentration of  solute molecules than the solution across a selectively permeable membrane.


incomplete dominance- condition in which a trait is intermediate between two parents.
inhalation - part of breathing in which the diaphragm contracts and air moves into the lungs.

insulin - peptide hormone produced by the islets of Langerhans in the pancreas that stores excess glucose by promoting the accumulation of glycogen in the liver.

ion -1st sem a positivly or negativly electrically charged atom or molecule.

ionic bond -1st sem chemical bond joining positive and negative ions.

isotonic - describes solutions with equal solute concentrations on either side of a selectively permeable membrane.


kinetic energy - energy of an object due to its motion.
kingdom - taxonomic category that contains phyla with similar characteristics.

krebs cycle - cyclic biochemical pathway of cellular respiration that uses pyruvate from glycolysis, releases CO2, and produces ATP, NADH and FADH2


law of independent assortment- law stating that pairs of genes separate independently of one another in meiosis.
law of segregation- law stating that pairs of genes separate in meiosis and each gamete receives one gene of a pair.

leukocyte- white blood cell; the primary cell of the immune system.

lipase- enzyme that breaks down fat molecules into fatty acids and glycerol.

lymphatic system- system of the body that collects and recycles fluids leaked from the cardiovascular system.

lymphocyte- type of white blood cell that matures in the organs of the lymphatic system.


macroevolution- change that occurs among species over time as new species evolve and old species become extinct.
meiosis-1st sem process in which the nucleus of a cell completes two successive divisions that produce four nuclei, each with a chromosome number that has been reduced by half.

melanocyte- type of cell in the basal layer of skin's epidermis that produces the dark pigment melanin.

menstruation- periodic flow of blood and tissue shed from the outer layer of the endometrium of a woman's uterus that occurs approximately every 28 days.

mesoderm- middle layer of embryonic tissue in animals from which the skeleton and muscles develop.

metabolism-1st sem sum of all chemical processes occurring in an organism.

metamorphosis-1st sem process of change through which an immature organism passes as it grows to adulthood.

metastasis- spread of malignant cells beyond their original site.

microevolution- change that occurs within a species over time.

mitochondrion- cell organelle of a eukaryotic cell that supplies the cell with ATP by performing oxidative respiration.

mitosis-1st sem process in which the nucleus of a cell divides into two nuclei, each with the same number and kind of chromosomes.

molecule-1st sem smallest particle of a substance that retains all the properties of the substance and is composed of two or more atoms bonded by the sharing of electrons.

monocots- monocotyledons; angiosperms with seeds that have a single cotyledon.

monohybird cross- cross involving one pair of contrasting traits.

multicellular- an organism that consists of more than one cell.

mutation-1st sem change in the DNA of a gene or chromosome.


natural selection-1st sem process by which populations change in response to their environment leave more offspring.
nitrogen fixation- process of combining nitrogen gas with hydrogen to form  ammonia.

nuclear envelope- 1st Sem double membrane that surrounds the cell nucleus.

nucleic acid- 1st Sem organic molecule that stores information for cell function; DNA or RNA.

nucleus-1st sem the organelle that houses the DNA of eukaryotic cells.


obligate anaerobe-1st sem organism that is poisoned by oxygen.
omnivore-1st sem animal that eats both plants and animals.

open circulatory system- system in which blood leaks out of blood vessels and bathes the body's tissues.

order- taxonomic category consisting of families with similar characteristics.

organelle-1st sem subcellular structure that has a special function.

origin- the end of the muscle that remains stationary during muscle contraction.

osmosis-1st sem movement of water through a membrane from area of high concentration to an area of low concentration.

osmotic pressure- increased water pressure that results from osmosis.

ovary- gamete-producing organ of the female reproductive system.

oviparoous- term that describes organisms that produce eggs that hatch outside the mother's body.

ovoviviparous- term that describes organisms that produce eggs that hatch inside the mother's body.

ovulation- the release of an ovum from a follicle.

ovum- and individual egg cell.

oxidative respiration- aerobic chemical reactions that follow glycolysis and that produce large amounts of ATP.


parasitism - type of predator feeds on but usually does not kill a larger organism.
Pathogen -1st sem a diease-causing agent.

peptidoglycan - the carbohydrate-protein compound that makes up the cell walls of eubacteria.

perennial plant - plant that lives for more than two years and may produce flowers, fruits, and seeds many times during its life.

peripheral nervous system - system in humans that includes nerves that bring information to the brain and transmit commands from it.

P generation - (parental generation) plants that displayed only one form of a particular trait.

photosynthesis -1st sem process by which organisms use light energy to produce ATP and other organic molecules from inorganic molecules.

pH scale - 1st Sem method of relating the hydrogen ion concentration in a solution.

phylum - a  taxonomic cat containing classes with similar characteristics.

pigment - molecule containing atoms that enable it to absorb certain wavelengths of light.

placenta - organ that nourishes the embryos of placental animals.

plasma - 1st sem nonnucular portion of blood.

plasma membrane - 1st sem thin layer on the surface of all cells, consisting mainly of lipids and proteins.

platelets - un-nucleated cell fragments that aid in blood clotting.

predation - an ecological interaction in which one organism feeds on another.

producer - 1st sem organism that makes its own food from energy and carbon atoms in its environment; autotroph.

prokaryotic cell -1st sem a cell without a nucleus.

protein -1st sem organic compound formed of one or more chains of poly peptides.

protist - a member of the kingdom Protista.

pseudopodium - extension of cytoplasm of the amoebae that enables it to move.

Punnett square - diagram used by biologists to predict the probable outcome of a cross.


radially symmetric - arrangement of the body parts around a central point.
radient energy - energy, such as light, that is transmitted in  waves that can travel through a vacuum.

reactant -1st sem substantance that is the starting material in a chemical reaction.

recessive trait - the trait that is not expressed in F1 generation after crossing.

respiration - simultaneous uptake of oxygen and release of carbon dioxide by the lungs.

retrovirus - virus that uses reverse transcriptase to transcribe DNA  from an RNA template

reverse transcriptase- enzyme in a retrivirus that manufactures DNA complementary to the virus's RNA.

robonucleic acid RNA- 1st sem a type of nucleic acid that participates in the expression of genes.

ribosome -1st sem cytoplasm organelle on which proteins are synthesized.


saturated fat - 1st sem fat that contains no C-C bonds.
scientific name-1st sem unique two-word name for a species in taxonomy; the first word is the genus, the second word is the species.

self-pollination- process by which a plant pollinates itself.

sexual reproduction- 1st sem reproduction in which gametes from opposites sexes or mating types unite to form a zygote.

sliding filament theory- explanation of muscle contraction in which myosin and actin filaments overlap and shorten each sarcomere.

slightly movable joint- a joint that permits limited movement of the bones.

smooth ER- endoplasmic reticulum with few or no ribosomes.

sodium-potassium pump- membrane channel through which sodium ions are exchanged with potassium ions, creating an abundance of sodium ions outside the cell wall.

solute-1st sem component of a solution in the lesser amount.

solution-1st sem homogeneous mixture of two or more substances.

solvent-1st sem component of a solution in the greater amount.

somatic nervous system- motor and sensory nerves that control the skeletal muscles and that are under conscious control.

speciation-1st sem process by which new species are formed.

species-1st sem group of organisms that look alike and are capable of producing fertile offspring in nature.

sjpirillum- spiral-shaped bacterial cell.

spongy bone- tissue in the human skeleton composed of hardened fibers interspersed with many spaces.

stamen- male reproductive structure of the flowering plant.

steriod- a class of lipids that includes cholesterol and some hormones.

steriod hormones- fat-souble hormones derived from cholesterol and secreted by the adrenal cortex, testis, ovary, and placenta.

subcutaneous tissue- layer of fat-rich cells just below the dermis.

symbiosis-1st sem ecological interaction in which two or more.

systemic circulation loop- series of vessels that carries blood to the tissue of the body and back to the heart.

systolic pressure- highest pressure that occurs during the pumping of the heart.


target cell- final destination of hormones, where they produce their effect.
taxonomy-1st sem science of naming and classifying organisms.

telophase- stage of mitosis in which a new nuclear envelope forms and spindle fibers disappear.

tendinitis - inflamed and painful tendons.

terrestrial -1st sem term that describes an organism with the ability to live on land.

theory -1st sem explanation based on a hypothesis that has been tested many times.

theory of endosymbiosis -1st sem theory that mitochondria and chloroplasts are the descendents of symbiotic eubacteris.

tissue - 1st sem group of cells with a common structure and function.

tissure culture - technique for growing pieces of living tissure in artificial media.

trachea - tube that carries air from the larynx to the lungs.

transmission electron microscope - (TEM) a microscope that produces a stream of electrons that passes through a specimen  and strikes a fluorescent screen.

transpiration - loss of water from a plant through its stomata.

tuber - a modified underground stem.

tumur - a mass of cells resulting from the proliferation of a cancerous cell.

Ttpe 1 diabetes - hereditary autoimmune disease in which the immune system attacks the islets if Langerhans in the pancreasa, causing abnormally low insulin secretion.

Type 2 diabetes - disease in which the number of insulin receptors is abnormally low while the level of insulin in the system is often higher than normal.


ulcer- hole in the lining of the stomach or small intestine caused by excessive acid.
unsaturated fat- 1st sem fat that contains C=C bonds.

uterus- hollow, muscular, pear-shaped organ of the female reproductive system in which the embryo and then the fetus develops.


vascular system- in plants, tissue that transport water and other materials.
vein- large vessel that carries blood toward the heart.

ventral- bottom surface of a bilaterally symmetrical animal.

venule- small vessels that carries blood from the capillaries to the veins.

vertebrate- animal with a back bone.

virulent- referring to the deadlines of a disease-causing agent.

virus- a strand of nucleic acid encased in a protein coat that can infect cells and replicate within them.

viviparous- term used to describe organisms whose young are born alive from egg cells that develop within the mother's body.

water vascular system- hydraulic system of echinoderms that aids in movement.


xylem- in plants, hard-walled cells that transport water and dissolved minerals up from the roots.


yeast- common name given to unicellular ascomycetes.
yellow marrow- soft tissue filling the cavity of a long bone where fat is stored.


zygotic meiosis- life cycle in which the zygote is the only diploid cell and undergoes meiosis immediately after it is formed.