WGU C453 CLINICAL MICROBIOLOGY FINAL EXAM
STUDY SET 2022/2023 UPDATE NEW VERSION
Bacteria Single-celled organism that do not have a cell nucleus and the membrane-enclosed intracellular
structures found in most other cells (Prokaryotic cell).
Gram-positive Bacteria Thick layer of peptidoglycan (20-80nm across). The peptidoglycan layer is closely
attached to the outer surface of the cell membrane. Retains crystal violet stains. Lack an outer
membrane and a periplasmic space.
Gram-negative Bacteria Cell wall is thinner, but more complex. Only 10-20% peptidoglycan. Contains an
outer membrane, leaving a very narrow periplasmic space. Does not retain crystal violet stain because of
large quantities of lipoproteins and lipopolysaccharides (endotoxin).
Acid-fast Bacteria Cell wall is thick, but consists of 60% lipids. Lipids make acid-fast organisms
impermeable to most other stains and protect them from acids and alkalis. Stain as gram-positive. Grow
slowly because the lipids impeded entry of nutrients.
Endotoxin Lipopolysaccharide (LPS). Part of the outer membrane of the cell wall of gram-negative
bacteria. It can cause fever and dilates blood vessels- causing BP to drop. Bacteria typically release this
when they are dying, so killing them increases the concentration of this toxic substance. Antibiotics
given late in the infection can cause worsening of symptoms or even death.
Wall-deficient Bacteria Protected by a strengthened cell membrane that contains sterols. Example:
mycobacterium paratuberculosis with Crohn's disease- a chronic disorder of the intestine.
Coccus Sphere shaped bacteria
Coccobacillus Short rod shaped bacteria (between cocci and bacilli)
,Vibrio Comma shaped bacteria
Bacillus Rod shaped bacteria
Spirillum Rigid, wavy shaped bacteria
Spirochete Corkscrew shape bacteria
Function of cell membrane To regulate movement of materials into and out of the cell by transport
mechanisms. It synthesizes cell wall components, assists with DNA replication, secretes proteins, carries
on respiration, and captures energy as ATP.
Function of the cell wall Helps maintain the characteristic shape of the cell and prevents the cell from
bursting when fluids flow into the cell by osmosis. Lies outside the cell membrane.
Peptidoglycan Single most important component of the bacterial cell wall.
Capsule Discrete layer of polysaccharides that protects the cell. Promotes infection by protecting the
bacterial cell from engulfment by predatory protozoa or WBC (phagocytes). Also mediates adherence of
cells to surfaces.
Pili Tiny, hallow projections that are used to attach bacteria to surfaces. Are NOT involved in movement.
Promote infection by transferring DNA amount bacteria- which in turn can transfer antibiotic resistance.
Can adhere to RBC and cause blood cells to clump.
Flagella Long, thin, helical appendages that allow bacteria to move.
, Endospore Helps the organism survive, and is not a means of reproduction. They are formed within the
cells, contain very little water and are highly resistant to heat, drying, acids, bases, certain disinfectants,
and even radiation. They are capable of surviving adverse environmental conditions for long periods of
time.
Chemotaxis Process of bacteria moving toward or away from substances in their environment. Towards-
positive, Away- Negative.
Bacteria that produce spores Bacillus, Clostridium
Helminths Worm-like organisms living in and feeding on live hosts, receiving nourishment and
protection while disrupting their hosts' nutrient absorption, causing weakness and disease. Example:
Flukes, tapeworms, adult round-worms of intestine, and roundworm larvae.
Zygomycota Bread molds
Ascomycota Sac fungi. Yeasts. Replication by sexual reproduction.
Basidiomycota Club fungi. Amanita and other mushrooms.
Deuteromycota Fungi imperfecti. Soil organisms.
Virus Tiny, non living particle that invades and then reproduces inside a living cell. Contain only one kind
of nucleic acid- either DNA or RNA (never both).
Naked virus Virus with only a nucleocapsid and no envelope.
Enveloped virus Have a bilayer membrane outside their capsids.
STUDY SET 2022/2023 UPDATE NEW VERSION
Bacteria Single-celled organism that do not have a cell nucleus and the membrane-enclosed intracellular
structures found in most other cells (Prokaryotic cell).
Gram-positive Bacteria Thick layer of peptidoglycan (20-80nm across). The peptidoglycan layer is closely
attached to the outer surface of the cell membrane. Retains crystal violet stains. Lack an outer
membrane and a periplasmic space.
Gram-negative Bacteria Cell wall is thinner, but more complex. Only 10-20% peptidoglycan. Contains an
outer membrane, leaving a very narrow periplasmic space. Does not retain crystal violet stain because of
large quantities of lipoproteins and lipopolysaccharides (endotoxin).
Acid-fast Bacteria Cell wall is thick, but consists of 60% lipids. Lipids make acid-fast organisms
impermeable to most other stains and protect them from acids and alkalis. Stain as gram-positive. Grow
slowly because the lipids impeded entry of nutrients.
Endotoxin Lipopolysaccharide (LPS). Part of the outer membrane of the cell wall of gram-negative
bacteria. It can cause fever and dilates blood vessels- causing BP to drop. Bacteria typically release this
when they are dying, so killing them increases the concentration of this toxic substance. Antibiotics
given late in the infection can cause worsening of symptoms or even death.
Wall-deficient Bacteria Protected by a strengthened cell membrane that contains sterols. Example:
mycobacterium paratuberculosis with Crohn's disease- a chronic disorder of the intestine.
Coccus Sphere shaped bacteria
Coccobacillus Short rod shaped bacteria (between cocci and bacilli)
,Vibrio Comma shaped bacteria
Bacillus Rod shaped bacteria
Spirillum Rigid, wavy shaped bacteria
Spirochete Corkscrew shape bacteria
Function of cell membrane To regulate movement of materials into and out of the cell by transport
mechanisms. It synthesizes cell wall components, assists with DNA replication, secretes proteins, carries
on respiration, and captures energy as ATP.
Function of the cell wall Helps maintain the characteristic shape of the cell and prevents the cell from
bursting when fluids flow into the cell by osmosis. Lies outside the cell membrane.
Peptidoglycan Single most important component of the bacterial cell wall.
Capsule Discrete layer of polysaccharides that protects the cell. Promotes infection by protecting the
bacterial cell from engulfment by predatory protozoa or WBC (phagocytes). Also mediates adherence of
cells to surfaces.
Pili Tiny, hallow projections that are used to attach bacteria to surfaces. Are NOT involved in movement.
Promote infection by transferring DNA amount bacteria- which in turn can transfer antibiotic resistance.
Can adhere to RBC and cause blood cells to clump.
Flagella Long, thin, helical appendages that allow bacteria to move.
, Endospore Helps the organism survive, and is not a means of reproduction. They are formed within the
cells, contain very little water and are highly resistant to heat, drying, acids, bases, certain disinfectants,
and even radiation. They are capable of surviving adverse environmental conditions for long periods of
time.
Chemotaxis Process of bacteria moving toward or away from substances in their environment. Towards-
positive, Away- Negative.
Bacteria that produce spores Bacillus, Clostridium
Helminths Worm-like organisms living in and feeding on live hosts, receiving nourishment and
protection while disrupting their hosts' nutrient absorption, causing weakness and disease. Example:
Flukes, tapeworms, adult round-worms of intestine, and roundworm larvae.
Zygomycota Bread molds
Ascomycota Sac fungi. Yeasts. Replication by sexual reproduction.
Basidiomycota Club fungi. Amanita and other mushrooms.
Deuteromycota Fungi imperfecti. Soil organisms.
Virus Tiny, non living particle that invades and then reproduces inside a living cell. Contain only one kind
of nucleic acid- either DNA or RNA (never both).
Naked virus Virus with only a nucleocapsid and no envelope.
Enveloped virus Have a bilayer membrane outside their capsids.
