Microbiology, 2021

E • Glossary 1209
the number of cells formed by cell division
is equal to the number of cells dying
stereoisomers isomers that differ in the
spatial arrangements of atoms
sterilant strong chemical that effectively
kills all microbes and viruses in or on an
inanimate item
sterile field specified area that is free of all
vegetative microbes, endospores, and
viruses
sterilization protocol that completely
removes all vegetative cells, endospores,
and viruses from an item
steroid lipid with complex, ringed
structures found in cell membranes and
hormones
sterol the most common type of steroid;
contains an OH group at one specific
position on one of the molecule’s carbon
rings
sticky ends short, single-stranded
complementary overhangs that may be
produced when many restriction enzymes
cut DNA
stigma light-sensing eyespot found in
Euglena
stop codon (nonsense codon) one of three
codons for which there is no tRNA with a
complementary anticodon; a signal within
the mRNA for termination of translation
stratum corneum a layer of dead,
keratinized cells that forms the uppermost
layer of the epidermis
strep throat (streptococcal pharyngitis)
bacterial pharyngitis caused by
Streptococcus pyogenes
streptococcal toxic shock-like syndrome
(STSS) condition similar to staphylococcal
toxic shock syndrome but with greater
likelihood of bacteremia, necrotizing
fasciitis, and acute respiratory distress
syndrome
stroma a gel-like fluid that makes up
much of a chloroplast’s volume, and in
which the thylakoids floats
strongyloidiasis soil-transmitted
intestinal infection caused by the
helminth Strongyloides stercoralis
structural formula graphic
representation of the molecular structure
showing how the atoms are arranged
structural isomers molecules composed
of the same numbers and types of atoms
but with different bonding sequences
subacute bacterial endocarditis form of
endocarditis in which damage to the
valves of the heart occurs over months as a
result of blood clot formation and
immune-response-induced fibrosis of the
valves
subclinical disease disease that does not
present any signs or symptoms
subcutaneous mycosis any fungal
infection that penetrates the epidermis
and dermis to enter deeper tissues
substrate chemical reactants of an
enzymatic reaction
substrate-level phosphorylation direct
method of ATP production in which a
high-energy phosphate group is removed
from an organic molecule and added to an
ADP molecule
subunit vaccine vaccine that contains
only key antigens as opposed to whole
pathogens
sugar-phosphate backbone alternating
sugar-phosphate structure composing the
framework of a nucleic acid strand that
results from phosphodiester bond
formation between nucleotides
sulfonamides (sulfa drugs) group of
structurally related synthetic
antimicrobial compounds that function as
antimetabolites, competitively inhibiting
an enzyme in the bacterial folic acid
synthesis pathway
superantigen class of exotoxin that
triggers a strong nonspecific immune
response with excessive production of
cytokines (cytokine storm) causing
inflammation, high fever, shock, and,
potentially, death
supercoiled extensive wrapping and
twisting of a DNA molecule, allowing the
DNA to fit within a small space
supercoiling process in which DNA is
underwound or overwound to fit inside a
cell
supercritical fluid molecule, commonly
carbon dioxide, brought to high pressures
to reach a state that has physical
properties between those of liquids and
gases, allowing it to effectively penetrate
surfaces and cells to form carbonic acid,
which lowers the pH of cells considerably,
leading to sterilization
superinfection secondary infection that
may develop as a result of long-term,
broad-spectrum antimicrobial use
superoxide dismutase enzyme that
catalyzes the breakdown of superoxide
anions
suppurative producing pus; purulent
surfactant group of chemical compounds
used for degerming; lower the surface
tension of water, creating emulsions that
mechanically carry away microorganisms
sweat gland one of numerous tubular
glands embedded in the dermis that
secretes the watery substance known as
perspiration
symbiosis any interaction between
different species that are associated with
each other within a community
symptom subjective experience of disease
felt by the patient
synapse junction between a neuron and
another cell
syncytia multinucleated cells that form
from the fusion of normal cells during
infections or other processes
syndrome group of signs and symptoms
characteristic of a particular disease
syngamy process in which haploid
gametes fuse
synthetic antimicrobial antimicrobial
developed from a chemical not found in
nature
syphilis an STI caused by the bacterium
Treponema pallidum
systemic autoimmune disease
autoimmune disease that affect the
organism as a whole, rather than a single
organ
systemic infection infection that has
spread to multiple locations or body
systems
systemic inflammatory response
syndrome (SIRS) severe inflammatory
response to the presence of microbes in
the blood; can lead to sepsis
systemic lupus erythematosus (SLE)
systemic autoimmune disease producing
inflammatory type III hypersensitivities as
antibodies form immune complexes with
nuclear and cytoplasmic antigens
systemic mycosis a fungal infection that
spreads throughout the body