MCB 100 UIUC FINAL EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE
2025/2026
Clostridium botulinum - Answers G+ Obligate anaerobe, produces heat-resistant endospores,
growing (or vegetative) cells produce an A-B type toxin that causes flaccid paralysis (flaccid =
limp, no muscle contraction), normal habitat is anaerobic soils and sediments, chemoautrophic,
degrades dead organic matter, ingestion of the toxin causes botulism. the toxin is used (in sub-
lethal doses) to treat nervous tics, reduce wrinkles and ease the pain of migraine headaches.
Listeria monocytogenes - Answers G+ a non-spore forming rod-shaped bacterium that may be
found in contaminated dairy products such as unpasteurized milk or cheese that is made from
non-pasteurized milk, can survive as an intracellular parasite within the cytoplasm of
macrophages and epithelial cells, can spread from cell-to cell without going through the
bloodstream by "punching" through the cell membranes, if Listeriosis symptoms appear, the
odds of death are high (~20%).
Enterococcus faecalis - Answers G+ a non-spore forming coccus, comes in chains, found in the
large intestines, can be an opportunistic pathogen that can cause peritonitis if it gets out of the
intestines and into the abdominal cavity
Streptococcus pneumonia - Answers G+ a non-spore forming coccus that comes in chains,
normally found in the upper respiratory tract, it is the leading cause of bacterial pneumonia (a
lung infection) but it is not the only bacterial species that can cause pneumonia, virulent strains
commonly produce a capsule that is made of polysaccharides, most strains are alpha-hemolytic
Streptococcus mutans - Answers G+ a non-spore forming coccus that comes in chains,
normally found in the mouth, it has a fermentative type of metabolism and excretes lactic acid.
it is a leading cause of tooth decay, the dextrin capsule becomes mineralized plaque when
calcium ions are leached out of the tooth enamel because of the acid
Lactobacillus bulgaricus - Answers G+ a non-spore forming Gram positive rod-shaped
bacterium thatgrows anaerobically and can convert milk sugar (lactose) to lactic acid, it is one
of two species of lactic acid bacteria used to make yogurt
Bacillus licheniformis - Answers G+ an endospore-forming Gram positive rod shaped bacterium
that can grow aerobically, under anaerobic conditions it can reduce nitrate to nitrogen, it is
common in the soil and is the source of the antibiotic bacitracin, which inhibits peptidoglycan
synthesis in other bacteria but not at the same step as penicillin
Mycoplasma pneumonia - Answers G+ this unusual bacterium lacks a cell wall, they have a
tough cytoplasmic membrane that contains ergosterol, they are very small cells that, , can
cause a lung infection
Streptomyces griseus - Answers G+ soil bacterium that is the cause of common scab in
potatoes, they are the source of the first aminoglycoside antibiotic that was discovered
, Corynebacterium diphtheria - Answers G+ a rod-shaped bacterium that forms palisades, infects
the throat, excretes a toxin that enters host cells and inactivates the 80S ribosomes, dead cells
hang down in the back of the throat like a gray curtain, most Americans are immunized against
the toxin (it's the "D" in the DPT shot)
Staphylococcus aureus - Answers G+ a non-spore forming coccus that comes in grape-like
clusters, often found on human skin or in the nose, catalase positive, colonies are frequently
yellow or orange, may cause infections of burns or wounds, may be involved in the formation of
boils, some strains produce a heat stable enterotoxin that can cause a form of food poisoning
Streptococcus pyogenes - Answers G+ a non-spore forming coccus that comes in chains, often
found in the upper respiratory tract, it is a leading cause of pharyngitis (sore throat) but it can
also cause pneumonia and skin infections (impetigo), involved in scarlet fever, usually beta-
hemolytic
Clostridium perfringens - Answers G+ Obligate anaerobe, produces heat-resistant endospores,
normal habitat is anaerobic soils and sediments, chemoautrophic, degrades dead organic
matter, it is a leading cause of gas gangrene ( a necrotic infection of wounds)
Mycobacterium tuberculosis - Answers G+ a slow growing irregular rod that is positive in the
acid-fast stain, it causes a highly contagious chronic lung infection, the cell wall contains wax-
like hydrophobic compounds, can survive and grow inside host phagocytic cells, Gram stain
results are unreliable
Bacillus anthracis - Answers G+ produces heat-resistant endospores, grows either aerobically or
anaerobically but best in the presence of air, can cause a fatal lung infection, can cause wound
infections (wool sorter's disease), most commonly seen in grazing animals and people that
work with grazing animals
Neisseria meningitis - Answers G- a bean-shaped diplococcus that is related to the causative
agent of gonorrhea, it can cause a life threatening infection of the meninges (tissue that covers
the spinal cord and brain)
Rickettsia rickettsia - Answers G- a tiny bacterium that is an obligate intracellular parasite and
absorbs ATP from the host cell, transmitted by ticks, causes Rocky Mountain spotted tick fever
Bordetella pertussis - Answers G- a Gram-negative coccobacillus that causes a potentially
severe upper respiratory infection commonly called whooping cough
Haemophilus aegyptius - Answers G- a glycolytic facultative anaerobe in the family
Pasteurellaceae, this Gram negative rod-shaped bacterium can cause conjunctivitis (pink-eye)
Treponema palladium - Answers G- a spirochete that is the causative agent of syphilis (a
sexually transmitted disease which if left untreated can damage the aorta, heart, brain, eyes and
bones)
2025/2026
Clostridium botulinum - Answers G+ Obligate anaerobe, produces heat-resistant endospores,
growing (or vegetative) cells produce an A-B type toxin that causes flaccid paralysis (flaccid =
limp, no muscle contraction), normal habitat is anaerobic soils and sediments, chemoautrophic,
degrades dead organic matter, ingestion of the toxin causes botulism. the toxin is used (in sub-
lethal doses) to treat nervous tics, reduce wrinkles and ease the pain of migraine headaches.
Listeria monocytogenes - Answers G+ a non-spore forming rod-shaped bacterium that may be
found in contaminated dairy products such as unpasteurized milk or cheese that is made from
non-pasteurized milk, can survive as an intracellular parasite within the cytoplasm of
macrophages and epithelial cells, can spread from cell-to cell without going through the
bloodstream by "punching" through the cell membranes, if Listeriosis symptoms appear, the
odds of death are high (~20%).
Enterococcus faecalis - Answers G+ a non-spore forming coccus, comes in chains, found in the
large intestines, can be an opportunistic pathogen that can cause peritonitis if it gets out of the
intestines and into the abdominal cavity
Streptococcus pneumonia - Answers G+ a non-spore forming coccus that comes in chains,
normally found in the upper respiratory tract, it is the leading cause of bacterial pneumonia (a
lung infection) but it is not the only bacterial species that can cause pneumonia, virulent strains
commonly produce a capsule that is made of polysaccharides, most strains are alpha-hemolytic
Streptococcus mutans - Answers G+ a non-spore forming coccus that comes in chains,
normally found in the mouth, it has a fermentative type of metabolism and excretes lactic acid.
it is a leading cause of tooth decay, the dextrin capsule becomes mineralized plaque when
calcium ions are leached out of the tooth enamel because of the acid
Lactobacillus bulgaricus - Answers G+ a non-spore forming Gram positive rod-shaped
bacterium thatgrows anaerobically and can convert milk sugar (lactose) to lactic acid, it is one
of two species of lactic acid bacteria used to make yogurt
Bacillus licheniformis - Answers G+ an endospore-forming Gram positive rod shaped bacterium
that can grow aerobically, under anaerobic conditions it can reduce nitrate to nitrogen, it is
common in the soil and is the source of the antibiotic bacitracin, which inhibits peptidoglycan
synthesis in other bacteria but not at the same step as penicillin
Mycoplasma pneumonia - Answers G+ this unusual bacterium lacks a cell wall, they have a
tough cytoplasmic membrane that contains ergosterol, they are very small cells that, , can
cause a lung infection
Streptomyces griseus - Answers G+ soil bacterium that is the cause of common scab in
potatoes, they are the source of the first aminoglycoside antibiotic that was discovered
, Corynebacterium diphtheria - Answers G+ a rod-shaped bacterium that forms palisades, infects
the throat, excretes a toxin that enters host cells and inactivates the 80S ribosomes, dead cells
hang down in the back of the throat like a gray curtain, most Americans are immunized against
the toxin (it's the "D" in the DPT shot)
Staphylococcus aureus - Answers G+ a non-spore forming coccus that comes in grape-like
clusters, often found on human skin or in the nose, catalase positive, colonies are frequently
yellow or orange, may cause infections of burns or wounds, may be involved in the formation of
boils, some strains produce a heat stable enterotoxin that can cause a form of food poisoning
Streptococcus pyogenes - Answers G+ a non-spore forming coccus that comes in chains, often
found in the upper respiratory tract, it is a leading cause of pharyngitis (sore throat) but it can
also cause pneumonia and skin infections (impetigo), involved in scarlet fever, usually beta-
hemolytic
Clostridium perfringens - Answers G+ Obligate anaerobe, produces heat-resistant endospores,
normal habitat is anaerobic soils and sediments, chemoautrophic, degrades dead organic
matter, it is a leading cause of gas gangrene ( a necrotic infection of wounds)
Mycobacterium tuberculosis - Answers G+ a slow growing irregular rod that is positive in the
acid-fast stain, it causes a highly contagious chronic lung infection, the cell wall contains wax-
like hydrophobic compounds, can survive and grow inside host phagocytic cells, Gram stain
results are unreliable
Bacillus anthracis - Answers G+ produces heat-resistant endospores, grows either aerobically or
anaerobically but best in the presence of air, can cause a fatal lung infection, can cause wound
infections (wool sorter's disease), most commonly seen in grazing animals and people that
work with grazing animals
Neisseria meningitis - Answers G- a bean-shaped diplococcus that is related to the causative
agent of gonorrhea, it can cause a life threatening infection of the meninges (tissue that covers
the spinal cord and brain)
Rickettsia rickettsia - Answers G- a tiny bacterium that is an obligate intracellular parasite and
absorbs ATP from the host cell, transmitted by ticks, causes Rocky Mountain spotted tick fever
Bordetella pertussis - Answers G- a Gram-negative coccobacillus that causes a potentially
severe upper respiratory infection commonly called whooping cough
Haemophilus aegyptius - Answers G- a glycolytic facultative anaerobe in the family
Pasteurellaceae, this Gram negative rod-shaped bacterium can cause conjunctivitis (pink-eye)
Treponema palladium - Answers G- a spirochete that is the causative agent of syphilis (a
sexually transmitted disease which if left untreated can damage the aorta, heart, brain, eyes and
bones)
