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BIO VOCABULARY
A
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.
B
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.

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C
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.
D
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.
E
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.

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

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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.
K
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
L
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.
M
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

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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.
N
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.
O
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.
P
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

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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.
R
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
S
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.
T
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.

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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.
U
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.
V
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.
W
water vascular system- hydraulic system of echinoderms that aids in
movement.
X
xylem- in plants, hard-walled cells that transport water and dissolved minerals
up from the roots.
Y
yeast- common name given to unicellular ascomycetes.
yellow marrow- soft tissue filling the cavity of a long bone where fat is stored.

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