Chamberlain University
2 MAXE • 242 SOIB
★ ★
C College of Nursing & Public Health
J O U R N E Y T O E X T R A O R D I N A R Y CO M PA S S I O N AT E C A R E
EST. 1889
BIOS 242 — Examination 2
F U N D A M E N TA LS O F M I C R O B I O LO G Y: M E TA B O L I S M , CO N T R O L & PAT H O G E N E S I S
INSTITUTION Chamberlain University COURSE CODE BIOS 242
PROGRAM Bachelor of Science in Nursing (BSN) ACADEMIC YEAR
EXAM TITLE Examination 2 – Metabolism, Control & Pathogenesis TOTAL QUESTIONS 50 Questions
COURSE TITLE Fundamentals of Microbiology FORMAT Multiple Choice — Select the Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each multiple-choice question.
▸ This comprehensive examination covers microbial nutrition and growth, enzymes, metabolism (aerobic/anaerobic respiration, fermentation), physical and chemical control methods,
antibiotics and resistance mechanisms, host-microbe interactions, pathogenesis, transmission, and epidemiology.
▸ Questions are drawn from the complete BIOS 242 Exam 2 review content.
▸ Correct answers and detailed rationales appear below each question for comprehensive review.
▸ All content reflects Chamberlain University BIOS 242 course competencies and learning objectives.
MICROBIAL METABOLISM, CONTROL & INFECTIOUS DISEASE Questions 1 – 50
1. A photoautotroph uses which energy source and carbon source?
A. Chemical energy; organic carbon
B. Light energy; CO₂
C. Light energy; organic carbon
D. Chemical energy; CO₂
CORRECT ANSWER B — Light energy; CO₂
RATIONALE Photoautotrophs (e.g., plants, cyanobacteria) use light as their energy source and CO₂ as their carbon source for photosynthesis. Option A describes
chemoheterotrophs (most pathogens). Option C describes photoheterotrophs (some bacteria). Option D describes chemoautotrophs (nitrogen-fixing bacteria).
2. Most human pathogens are classified as which nutritional type?
A. Photoautotrophs
B. Chemoautotrophs
C. Chemoheterotrophs
D. Photoheterotrophs
CORRECT ANSWER C — Chemoheterotrophs
RATIONALE Most human pathogens are chemoheterotrophs—they obtain energy from chemical compounds and carbon from organic sources (the host's tissues).
Photoautotrophs (A) are photosynthetic. Chemoautotrophs (B) use CO₂ as carbon. Photoheterotrophs (D) are rare and use light energy with organic carbon.
3. A saprobe is an organism that:
A. Feeds on a living host and causes disease
B. Feeds on dead matter (decomposer)
C. Produces its own food through photosynthesis
D. Requires a host cell to replicate
CORRECT ANSWER B — Feeds on dead matter (decomposer)
RATIONALE Saprobes (saprophytes) are decomposers that obtain nutrients from dead organic matter. They secrete enzymes to digest material externally and absorb the
breakdown products. Fungi and many bacteria are saprobic. Option A describes a parasite. Option D describes a virus.
4. A psychrophile lives in which type of environment?
A. High salt concentrations
B. Cold temperatures, often associated with food spoilage
C. Hot springs at high temperatures
D. Moderate temperatures of 20–45°C
CORRECT ANSWER B — Cold temperatures, often associated with food spoilage
RATIONALE Psychrophiles are cold-loving organisms that grow optimally at low temperatures (−20°C to 20°C). They are found in permanently cold environments and are
responsible for food spoilage in refrigerated products. Option A describes halophiles. Option C describes thermophiles. Option D describes mesophiles.
, 5. Listeria is an example of which type of organism based on temperature preference?
A. Psychrophile
B. Thermophile
C. Psychrotolerant
D. Hyperthermophile
CORRECT ANSWER C — Psychrotolerant
RATIONALE Psychrotolerant organisms can grow at refrigerator temperatures (4°C) but have optimal growth at warmer temperatures. Listeria monocytogenes is a classic
example—it can grow in refrigerated foods, making it a significant food safety concern. True psychrophiles (A) require cold temperatures for optimal growth.
6. Human pathogens typically grow best in which temperature range?
A. 0–15°C
B. 20–45°C (mesophilic range)
C. 50–80°C
D. Above 80°C
CORRECT ANSWER B — 20–45°C (mesophilic range)
RATIONALE Mesophiles grow optimally between 20–45°C, which includes human body temperature (37°C). Most human pathogens are mesophiles because they are adapted
to grow at host body temperature. Psychrophiles (A) prefer cold. Thermophiles (C) and hyperthermophiles (D) prefer hot environments.
7. An obligate anaerobe is an organism that:
A. Requires a constant supply of oxygen to live
B. Cannot live in the presence of oxygen
C. Can survive with or without oxygen but prefers oxygen
D. Requires low oxygen levels for growth
CORRECT ANSWER B — Cannot live in the presence of oxygen
RATIONALE Obligate anaerobes are killed by oxygen because they lack enzymes (superoxide dismutase, catalase) to detoxify reactive oxygen species. They grow only in
oxygen-free environments. Option A describes obligate aerobes. Option C describes facultative anaerobes. Option D describes microaerophiles.
8. A facultative anaerobe is best described as an organism that:
A. Requires oxygen and cannot survive without it
B. Is killed by any exposure to oxygen
C. Can survive with or without oxygen but prefers oxygen (flexible)
D. Requires only trace amounts of oxygen
CORRECT ANSWER C — Can survive with or without oxygen but prefers oxygen (flexible)
RATIONALE Facultative anaerobes are metabolically flexible—they perform aerobic respiration when oxygen is available (producing more ATP) and switch to fermentation or
anaerobic respiration when oxygen is absent. E. coli is a classic example. Option A describes obligate aerobes. Option B describes obligate anaerobes.
9. An organism that does not use oxygen but tolerates it and relies on fermentation is called:
A. Microaerophile
B. Obligate aerobe
C. Aerotolerant
D. Facultative anaerobe
CORRECT ANSWER C — Aerotolerant
RATIONALE Aerotolerant organisms do not use oxygen for metabolism (they rely solely on fermentation) but possess enzymes to detoxify reactive oxygen species, allowing
them to survive in oxygen's presence. Streptococcus species are examples. Microaerophiles (A) require low oxygen. Facultative anaerobes (D) switch between
aerobic and anaerobic metabolism.
10. An acidophile thrives in which type of environment?
A. Basic (alkaline) pH environment
B. Neutral pH environment
C. Acidic pH environment
D. High salt environment
CORRECT ANSWER C — Acidic pH environment
RATIONALE Acidophiles grow optimally at low pH (acidic conditions). Examples include Helicobacter pylori, which survives stomach acid. Neutrophiles (B) prefer neutral pH
and include most human pathogens. Alkalinophiles (A) prefer basic conditions. Halophiles (D) prefer high salt.
11. In the bacterial growth curve, the lag phase is characterized by:
A. Rapid exponential growth and division
B. Nutrient depletion and cell death
C. Adaptation to the environment with no cell division
D. Equal rates of cell growth and cell death
CORRECT ANSWER C — Adaptation to the environment with no cell division
RATIONALE During the lag phase, bacteria are adapting to their new environment—synthesizing enzymes and adjusting metabolism—but not yet dividing. Option A describes
the log (exponential) phase. Option B describes the death phase. Option D describes the stationary phase.
2 MAXE • 242 SOIB
★ ★
C College of Nursing & Public Health
J O U R N E Y T O E X T R A O R D I N A R Y CO M PA S S I O N AT E C A R E
EST. 1889
BIOS 242 — Examination 2
F U N D A M E N TA LS O F M I C R O B I O LO G Y: M E TA B O L I S M , CO N T R O L & PAT H O G E N E S I S
INSTITUTION Chamberlain University COURSE CODE BIOS 242
PROGRAM Bachelor of Science in Nursing (BSN) ACADEMIC YEAR
EXAM TITLE Examination 2 – Metabolism, Control & Pathogenesis TOTAL QUESTIONS 50 Questions
COURSE TITLE Fundamentals of Microbiology FORMAT Multiple Choice — Select the Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each multiple-choice question.
▸ This comprehensive examination covers microbial nutrition and growth, enzymes, metabolism (aerobic/anaerobic respiration, fermentation), physical and chemical control methods,
antibiotics and resistance mechanisms, host-microbe interactions, pathogenesis, transmission, and epidemiology.
▸ Questions are drawn from the complete BIOS 242 Exam 2 review content.
▸ Correct answers and detailed rationales appear below each question for comprehensive review.
▸ All content reflects Chamberlain University BIOS 242 course competencies and learning objectives.
MICROBIAL METABOLISM, CONTROL & INFECTIOUS DISEASE Questions 1 – 50
1. A photoautotroph uses which energy source and carbon source?
A. Chemical energy; organic carbon
B. Light energy; CO₂
C. Light energy; organic carbon
D. Chemical energy; CO₂
CORRECT ANSWER B — Light energy; CO₂
RATIONALE Photoautotrophs (e.g., plants, cyanobacteria) use light as their energy source and CO₂ as their carbon source for photosynthesis. Option A describes
chemoheterotrophs (most pathogens). Option C describes photoheterotrophs (some bacteria). Option D describes chemoautotrophs (nitrogen-fixing bacteria).
2. Most human pathogens are classified as which nutritional type?
A. Photoautotrophs
B. Chemoautotrophs
C. Chemoheterotrophs
D. Photoheterotrophs
CORRECT ANSWER C — Chemoheterotrophs
RATIONALE Most human pathogens are chemoheterotrophs—they obtain energy from chemical compounds and carbon from organic sources (the host's tissues).
Photoautotrophs (A) are photosynthetic. Chemoautotrophs (B) use CO₂ as carbon. Photoheterotrophs (D) are rare and use light energy with organic carbon.
3. A saprobe is an organism that:
A. Feeds on a living host and causes disease
B. Feeds on dead matter (decomposer)
C. Produces its own food through photosynthesis
D. Requires a host cell to replicate
CORRECT ANSWER B — Feeds on dead matter (decomposer)
RATIONALE Saprobes (saprophytes) are decomposers that obtain nutrients from dead organic matter. They secrete enzymes to digest material externally and absorb the
breakdown products. Fungi and many bacteria are saprobic. Option A describes a parasite. Option D describes a virus.
4. A psychrophile lives in which type of environment?
A. High salt concentrations
B. Cold temperatures, often associated with food spoilage
C. Hot springs at high temperatures
D. Moderate temperatures of 20–45°C
CORRECT ANSWER B — Cold temperatures, often associated with food spoilage
RATIONALE Psychrophiles are cold-loving organisms that grow optimally at low temperatures (−20°C to 20°C). They are found in permanently cold environments and are
responsible for food spoilage in refrigerated products. Option A describes halophiles. Option C describes thermophiles. Option D describes mesophiles.
, 5. Listeria is an example of which type of organism based on temperature preference?
A. Psychrophile
B. Thermophile
C. Psychrotolerant
D. Hyperthermophile
CORRECT ANSWER C — Psychrotolerant
RATIONALE Psychrotolerant organisms can grow at refrigerator temperatures (4°C) but have optimal growth at warmer temperatures. Listeria monocytogenes is a classic
example—it can grow in refrigerated foods, making it a significant food safety concern. True psychrophiles (A) require cold temperatures for optimal growth.
6. Human pathogens typically grow best in which temperature range?
A. 0–15°C
B. 20–45°C (mesophilic range)
C. 50–80°C
D. Above 80°C
CORRECT ANSWER B — 20–45°C (mesophilic range)
RATIONALE Mesophiles grow optimally between 20–45°C, which includes human body temperature (37°C). Most human pathogens are mesophiles because they are adapted
to grow at host body temperature. Psychrophiles (A) prefer cold. Thermophiles (C) and hyperthermophiles (D) prefer hot environments.
7. An obligate anaerobe is an organism that:
A. Requires a constant supply of oxygen to live
B. Cannot live in the presence of oxygen
C. Can survive with or without oxygen but prefers oxygen
D. Requires low oxygen levels for growth
CORRECT ANSWER B — Cannot live in the presence of oxygen
RATIONALE Obligate anaerobes are killed by oxygen because they lack enzymes (superoxide dismutase, catalase) to detoxify reactive oxygen species. They grow only in
oxygen-free environments. Option A describes obligate aerobes. Option C describes facultative anaerobes. Option D describes microaerophiles.
8. A facultative anaerobe is best described as an organism that:
A. Requires oxygen and cannot survive without it
B. Is killed by any exposure to oxygen
C. Can survive with or without oxygen but prefers oxygen (flexible)
D. Requires only trace amounts of oxygen
CORRECT ANSWER C — Can survive with or without oxygen but prefers oxygen (flexible)
RATIONALE Facultative anaerobes are metabolically flexible—they perform aerobic respiration when oxygen is available (producing more ATP) and switch to fermentation or
anaerobic respiration when oxygen is absent. E. coli is a classic example. Option A describes obligate aerobes. Option B describes obligate anaerobes.
9. An organism that does not use oxygen but tolerates it and relies on fermentation is called:
A. Microaerophile
B. Obligate aerobe
C. Aerotolerant
D. Facultative anaerobe
CORRECT ANSWER C — Aerotolerant
RATIONALE Aerotolerant organisms do not use oxygen for metabolism (they rely solely on fermentation) but possess enzymes to detoxify reactive oxygen species, allowing
them to survive in oxygen's presence. Streptococcus species are examples. Microaerophiles (A) require low oxygen. Facultative anaerobes (D) switch between
aerobic and anaerobic metabolism.
10. An acidophile thrives in which type of environment?
A. Basic (alkaline) pH environment
B. Neutral pH environment
C. Acidic pH environment
D. High salt environment
CORRECT ANSWER C — Acidic pH environment
RATIONALE Acidophiles grow optimally at low pH (acidic conditions). Examples include Helicobacter pylori, which survives stomach acid. Neutrophiles (B) prefer neutral pH
and include most human pathogens. Alkalinophiles (A) prefer basic conditions. Halophiles (D) prefer high salt.
11. In the bacterial growth curve, the lag phase is characterized by:
A. Rapid exponential growth and division
B. Nutrient depletion and cell death
C. Adaptation to the environment with no cell division
D. Equal rates of cell growth and cell death
CORRECT ANSWER C — Adaptation to the environment with no cell division
RATIONALE During the lag phase, bacteria are adapting to their new environment—synthesizing enzymes and adjusting metabolism—but not yet dividing. Option A describes
the log (exponential) phase. Option B describes the death phase. Option D describes the stationary phase.
