Microbiology, 2021

E • Glossary 1187
occurring
ectoplasm outer, more gelatinous layer of
cytoplasm under a protist cell membrane
edema swelling due to accumulation of
fluid and protein in tissue as a result of
increased permeability of capillary walls
during an inflammatory response; chronic
edema can also result from blockage of
lymphatic vessels, as in the case of
elephantiasis
effector cells activated cells of cellular
immunity that are involved in the
immediate immune response, primarily to
defend the body against pathogens
electron carrier cellular molecule that
accepts high-energy electrons from
reduced molecules like foods and later
serves as an electron donor in subsequent
redox reactions
electron microscope a type of microscope
that uses short-wavelength electron
beams rather than light to increase
magnification and resolution
electron transport system (ETS) series of
membrane-associated protein complexes
and associated mobile accessory electron
carriers important in the generation of the
proton motive force required for ATP
production by chemiosmosis; the last
component involved in the cellular
respiration of glucose
electroporation a genetic engineering
technique in which cells are exposed to a
short electric pulse, inducing them to take
up DNA molecules from their environment
elementary bodies metabolically and
reproductively inactive, endospore-like
form of intracellular bacteria that spreads
infection outside of cells
elongation in DNA replication stage of
DNA replication during which DNA
polymerase adds nucleotides,
complementary to the parental strand, to
the 3’ end of a growing DNA strand
elongation in transcription stage of
transcription during which RNA
polymerase extends the RNA molecule by
adding RNA nucleotides, complementary
to the template DNA strand
elongation of translation stage of
translation during which amino acids are
added one by one to the C-terminus of the
growing polypeptide
Embden-Meyerhof-Parnas (EMP)
pathway type of glycolysis found in
animals and the most common in
microbes
emerging infectious disease a disease
that is new to the human population or has
increased in prevalence over the previous
20 years
enantiomers stereoisomers that are
mirror images of each other and
nonsuperimposable
encephalitis inflammation of the tissues
of the brain
encystment the process of forming a cyst
endemic disease an illness that is
constantly present (often at low levels) in a
population
endergonic reaction chemical reaction
that requires energy beyond activation
energy to occur
endocarditis inflammation of the
endocardium, especially the heart valves
endocrine function refers to a cytokine
signal released from a cell and carried by
the bloodstream to a distant recipient cell
endocytosis the uptake of molecules
through plasma membrane invagination
and vacuole/vesicle formation
endomembrane system a series of
organelles (endoplasmic reticulum, Golgi
apparatuses, lysosomes, and transport
vesicles) arranged as membranous
tubules, sacs, and disks that synthesize
many cell components
endoplasm inner, more fluid layer of
cytoplasm under a protist cell membrane
(inside of the ectoplasm)
endoplasmic reticulum part of the
endomembrane system that is an
interconnected array of tubules and
flattened sacs with a single lipid bilayer
that may be either rough or smooth;
important in synthesizing proteins and
lipids
endospore a cellular structure formed by
some bacteria in response to adverse
conditions; preserves DNA of the cell in a
dormant state until conditions are
favorable again
endospore staining a differential staining
technique that uses two stains to make
bacterial endospores appear distinct from
the rest of the cell
endosymbiotic theory the theory that
mitochondria and chloroplasts arose as a
result of prokaryotic cells establishing a
symbiotic relationship within a eukaryotic
host
endothelia layer of epithelial cells lining
blood vessels, lymphatics, the blood-brain
barrier, and some other tissues
endotoxin lipid A component of
lipopolysaccharides in the outer
membrane of gram-negative bacteria
enriched media media that contain
additional essential nutrients to support
growth
enrichment culture media providing
growth conditions that favor the
expansion of an organism present in low
numbers
enteric bacteria of the family
Enterobacteriaceae, which live in the
human intestinal tract
enteritis inflammation of the lining of the
intestine
enterobiasis intestinal infection caused
by the pinworm Enterobius vermicularis
enterohemorrhagic E. coli (EHEC) E. coli
bacteria that cause severe gastrointestinal
illness with potential serious
complications such as hemolytic uremic
syndrome
enteroinvasive E. coli (EIEC) E. coli
bacteria that cause relatively mild
gastrointestinal illness
enteropathogenic E. coli (EPEC) E. coli
bacteria that cause serious
gastrointestinal illness
enterotoxigenic E. coli (ETEC) E. coli
bacteria that cause a relatively mild illness
commonly called traveler’s diarrhea
enterotoxin toxin that affects the
intestines
Entner-Doudoroff (ED) pathway
alternative glycolytic pathway used by
some bacteria
enveloped virus a virus formed with a
nucleic-acid packed capsid surrounded by
a lipid layer
enzyme catalyst for biochemical reactions
inside cells
enzyme immunoassay (EIA) type of assay
wherein an enzyme is coupled to an
antibody; addition of a chromogenic
substrate for the antibody allows