competitive inhibition chemical compounds that
bind to the active site of the enzyme and inhibit
enzymatic reactions. (2.2)
complementary pairings of bases between nucleic
acid strands. The two strands of a DNA double
helix are complementary with each other — each
purine base pairs with a pyrimidine base on the
opposite strand (A pairs with T or U, and C pairs
with G). (7.2)
condensation type of reaction in which two
molecules react to form water and another
molecule. This type of reaction is also known
as dehydration synthesis. (1.3)
cones colour receptors in the eye. (5.3)
conjunctiva the thin, transparent membrane that
covers the cornea and is kept moist by tears. (5.3)
conservative theory the theory stating that, in the
replication of DNA, the two new strands form
one molecule, while the two original strands
re-form the original molecule. (7.3)
convergent evolution evolutionary process in which
similar traits arise in two or more species
because each species has independently adapted
to similar environmental conditions, not because
they share a common ancestor. (12.3)
copy DNA (cDNA) double-stranded molecule of
DNA containing only the coding portions of the
eukaryotic gene. (9.3)
co-repressor molecule that combines with a
repressor protein, causing the repressor protein
to have an increased affinity for the operator.
When the repressor protein is bound to the
operator, transcription is blocked. (8.4)
cornea the clear part of the sclera at the front of the
eye. (5.3)
corpus callosum layer of white matter made up of
axons that joins the two hemispheres of the
cerebral cortex in the brain. (5.1)
corpus luteum follicle that has been emptied of its
egg. The empty follicle produces progesterone.
(6.3)
cortex (renal) the outer part of the kidney, where
the glomerulus, Bowman’s capsule, proximal
tubule, and distal tubule of the nephrons are
located. (4.2)
coupled reaction combinations of reactions in
which the energy released by an exothermic
reaction can be used to drive an endothermic
reaction. (2.3)
covalent bond chemical bond formed by the sharing
of electrons between two atoms. (1.1)
Cowper’s gland gland in human males that secretes
an alkaline fluid that neutralizes the acidity of
the female reproductive tract during sexual
intercourse. (6.3)
cryptic coloration structural adaptation
characterized by camouflaging shape and
coloring, enabling species to hide from predators.
(12.1)
cyclic photophosphorylation addition of a
phosphate group to ADP to form ATP. The
process uses energy from an electron transport
chain in which electrons are recycled in the
photosystem. (3.3)
cytochrome c mitochondrial protein involved in
respiration. The amino acid sequence of this
protein is used to indicate relatedness among
species. (10.3)
cytochromes electron carriers in the electron
transport chain. (3.2)
cytosine (C) one of four nitrogen-containing bases in
a nucleotide that make up DNA and RNA. (7.1)
cytosol fluid medium within a cell. (1.3)
cytotoxic T cell lymphocyte that binds to an
infected cell and then destroys it by puncturing
its membrane. (4.4)deamination the removal of an amino group. (3.2)
death in population dynamics, a factor that
decreases a population. (14.2)
decomposer organism that obtains its nutrition from
dead organisms and animal waste. The organism
breaks down larger organic molecules into
smaller nutrients and returns them to the abiotic
environment. (13.2)
deforestation the large-scale cutting down of forests
by humans. (15.3)
demographic transition period of change in the
growth rate (r) of a population. (15.1)
demography the study of populations, especially
population size, density, age structure, and
growth. (14.1)
dendrite the primary site on a nerve cell (neuron)
for receiving signals from other neurons. There
may be anywhere from one to several thousand
dendrites on each neuron. (5.1)
density the number of individuals per unit of area
or volume in a population. (14.1)
density-dependent factor variable, such as
competition for resources, that affects the growth
of a population when there is an increased
number of individuals in a given area. (14.3)
density-independent factor variable, such as
climate, that affects the growth of a population
regardless of the number of individuals in the
population in a given area. (14.3)
deoxyribonucleic acid DNA, also called
deoxyribose nucleic acid. A nucleic acid
consisting of long chains of individualD
Glossary • MHR 573