Microbiology, 2021

E • Glossary 1183
chromosome discrete DNA structure
within a cell that controls cellular
activities
chronic disease any disease that
progresses and persists over a long time
chronic granulomatous disease primary
immunodeficiency caused by an impaired
ability of phagocytic cells to kill ingested
bacteria in the phagolysosome
chronic wasting disease prion disease of
deer and elk in the United States and
Canada
cilia (singular: cilium) short filamentous
structures found on some eukaryotic cells;
each is composed of microtubules in a 9+2
array, and may be used for locomotion,
feeding, and/or movement of extracellular
particles that come in contact with the cell
ciliated epithelial cells hair-like cells in
the respiratory tract that beat, pushing
mucus secretions and trapped debris away
from the sensitive tissues of the lungs
ciliates protists with cilia (Ciliophora),
including Paramecium and Stentor,
classified within the Chromalveolata
cisternae the sacs of the endoplasmic
reticulum
citric acid cycle see Krebs cycle
class switching genetic rearrangement of
constant region gene segments in plasma
cells to switch antibody production from
IgM to IgG, IgA, or IgE
clindamycin semisynthetic protein
synthesis inhibitor of the lincosamide
class that binds to the 50S subunit,
inhibiting peptide bond formation
clone a genetically identical cell or
individual
Clostridium perfringens gastroenteritis
relatively mild gastrointestinal illness
caused by C. perfringens
clusters of differentiation (CD) cellsurface
glycoproteins that serve to identify
and distinguish white blood cells
coagulase enzyme that causes the
activation of fibrinogen to form fibrin,
promoting clotting of the blood
coarse focusing knob a knob on a
microscope that produces relatively large
movements to adjust focus
coccidioidomycosis disease caused by the
highly infectious fungal pathogen
Coccidioides immitis and related species
codon three-nucleotide sequence within
mRNA that specifies a particular amino
acid to be incorporated into the
polypeptide being synthesized
coenocyte multinucleated eukaryotic cell
that forms as a result of multiple rounds of
nuclear division without the
accompanying division of the plasma
membrane
coenocytic hyphae nonseptate hyphae
that are multinucleate and lack cell walls
or membranes between cells;
characteristic of some fungi
coenzyme organic molecule required for
proper enzyme function that is not
consumed and is reusable
cofactor inorganic ion that helps stabilize
enzyme conformation and function
cognate amino acid amino acid added to a
specific tRNA molecule that correctly
corresponds to the tRNA’s anticodon and,
hence, the mRNA’s codon, reflecting the
genetic code
cohort method a method used in
observational studies in which a group of
individuals is followed over time and
factors potentially important in the
development of disease are evaluated
colistin membrane-active polymyxin that
was historically used for bowel
decontamination but now used for
systemic infections with drug-resistant
pathogens
colitis inflammation of the large intestine
collagenase enzyme that digests collagen,
the dominant protein in connective tissue
colony-forming unit (CFU) a counting
quantity represented by a colony formed
on solid medium from a single cell or a few
cells
commensalism type of symbiosis in
which one population benefits and the
other is not affected
commercial sterilization type of
sterilization protocol used in food
production; uses conditions that are less
harsh (lower temperatures) to preserve
food quality but still effectively destroy
vegetative cells and endospores of
common foodborne pathogens such as
Clostridium botulinum
common cold most common cause of
rhinitis in humans; associated with a
variety of adenoviruses, coronaviruses,
and rhinoviruses
common source spread a mode of disease
transmission in which every infection
originates from the same source
communicable able to be transmitted
directly or indirectly from one person to
another
community group of interacting
populations of organisms
competitive inhibitor molecule that binds
to an enzyme’s active site, preventing
substrate binding
competitive interactions interactions
between populations in which one of them
competes with another for resources
complement activation cascading
activation of the complement proteins in
the blood, resulting in opsonization,
inflammation, and lysis of pathogens
complement fixation test test for
antibodies against a specific pathogen
using complement-mediated hemolysis
complement system series of proteins
that can become activated in the presence
of invading microbes, resulting in
opsonization, inflammation, and lysis of
pathogens
complementary base pairs base pairing
due to hydrogen bonding that occurs
between a specific purine and a specific
pyrimidine; A bonds with T (in DNA), and
C bonds with G
complementary DNA (cDNA) a DNA
molecule complementary to mRNA that is
made through the activity of reverse
transcriptase
complex media media that contain
extracts of animals and plants that are not
chemically defined
complex virus virus shape that often
includes intricate characteristics not seen
in the other categories of capsid
compound microscope a microscope that
uses multiple lenses to focus light from the
specimen
condenser lens a lens on a microscope
that focuses light from the light source
onto the specimen
conditional mutation mutant form of a
gene whose mutant phenotype is
expressed only under certain
environmental conditions