Chamberlain University
2 MAXE • 242 SOIB
★ ★
C College of Nursing & Health Professions
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
M I C R O B I A L N U T R I T I O N , M E TA B O L I S M , G R O W T H & A N T I M I C R O B I A L CO N T R O L
INSTITUTION Chamberlain University COURSE CODE BIOS 242
PROGRAM Bachelor of Science in Nursing (BSN) ACADEMIC YEAR
EXAM TITLE Examination 2 — Nutrition, Metabolism & Control TOTAL QUESTIONS 25 Questions
COURSE TITLE Fundamentals of Microbiology FORMAT Multiple Choice — Select the Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This examination covers microbial nutrition, metabolism, growth phases, control methods, and antimicrobial drugs.
▸ All content reflects BIOS 242 learning objectives and foundational microbiology for nursing practice.
▸ Correct answers and detailed rationales appear below each question for exam preparation purposes.
▸ Pay careful attention to oxygen requirements, enzyme function, and antibiotic mechanisms of action.
SECTION I — NUTRITION, METABOLISM, GROWTH, CONTROL & ANTIMICROBIAL DRUGS Questions 1 – 25
1. A photoautotroph derives its energy and carbon from which sources?
A. Energy from chemical compounds; carbon from organic matter
B. Energy from light rays; carbon from CO₂ in the air (inorganic source)
C. Energy from light; carbon from consuming other organisms
D. Energy from inorganic materials; carbon from rocks
CORRECT ANSWER B — Energy from light rays; carbon from CO₂ in the air (inorganic source)
RATIONALE A photoautotroph gains energy from light (through photosynthesis) and uses carbon dioxide (CO₂) from the air as its carbon source — an inorganic form of carbon.
Examples include photosynthetic organisms: algae, plants, and cyanobacteria. Photoautotrophs are the basis of most food webs because they produce organic
compounds from inorganic carbon. A chemoheterotroph (like humans) derives both energy and carbon from consumed organic food. A chemoautotroph gets
energy from chemical compounds and carbon from inorganic sources. A lithoautotroph gets energy from inorganic materials.
2. Humans are classified as chemoheterotrophs. What does this mean?
A. We gain energy from light and carbon from CO₂
B. We derive both energy and carbon from the organic food we consume
C. We produce our own food through photosynthesis
D. We gain energy from inorganic materials like rocks
CORRECT ANSWER B — We derive both energy and carbon from the organic food we consume
RATIONALE Chemoheterotrophs derive both their energy (from chemical energy in consumed food) and their carbon source (from the organic compounds in that food) from
external organic sources. Humans, all animals, fungi, and many bacteria are chemoheterotrophs — they are nutritionally dependent on other life forms. An
autotroph ("self-feeder") uses CO₂ as its carbon source and is NOT nutritionally dependent on other living things. A phototroph gains energy from light. A
chemotroph gains energy from chemical compounds. A heterotroph must obtain carbon in organic form.
3. Aerobic respiration differs from anaerobic respiration in that aerobic respiration:
A. Does not require any electron acceptors
B. Uses oxygen (O₂) as the final electron acceptor in the electron transport chain
C. Produces less ATP than fermentation
D. Occurs only in the cytoplasm without mitochondria
CORRECT ANSWER B — Uses oxygen (O₂) as the final electron acceptor in the electron transport chain
RATIONALE Aerobic respiration is the principal energy-yielding pathway in which the final electron acceptor in the electron transport chain is oxygen (O₂). It produces the
largest amount of ATP — approximately 36–38 ATP per glucose molecule. In contrast, anaerobic respiration does not use oxygen as the final electron acceptor;
instead, it uses other molecules (nitrate, sulfate). Fermentation is the incomplete oxidation of glucose without oxygen, produces only a small amount of ATP (2 ATP
from glycolysis), and uses organic compounds as terminal electron acceptors, resulting in products like alcohol or acid.
, 4. What is the difference between active transport and facilitated diffusion?
A. Both require ATP and transport against the concentration gradient
B. Active transport uses ATP to move substances against the concentration gradient; facilitated diffusion uses a carrier protein but does not require energy and moves
with the gradient
C. Facilitated diffusion requires ATP; active transport does not
D. Active transport only moves water; facilitated diffusion only moves glucose
CORRECT ANSWER B — Active transport uses ATP to move substances against the concentration gradient; facilitated diffusion uses a carrier protein but does not require
energy and moves with the gradient
RATIONALE Active transport requires ATP energy to transport substances against their concentration gradient (from low to high concentration). Facilitated diffusion uses a
specific carrier protein that binds to a molecule and changes shape to carry it across the membrane, but moves with the concentration gradient (high to low) and
does NOT require energy. Simple diffusion is the movement of molecules from higher to lower concentration without a carrier. Group translocation is a form of
active transport that chemically modifies the substance during transport. Osmosis is the movement of water across a selectively permeable membrane.
5. An organism that CANNOT grow or metabolize without oxygen is classified as a(n):
A. Obligate anaerobe — will die if oxygen is present
B. Facultative aerobe — does not require oxygen but can use it
C. Obligate aerobe — absolutely requires oxygen to grow and metabolize
D. Aerotolerant anaerobe — does not use oxygen but tolerates it
CORRECT ANSWER C — Obligate aerobe — absolutely requires oxygen to grow and metabolize
RATIONALE An obligate aerobe CANNOT grow or metabolize without oxygen — it has an absolute requirement for O₂. An obligate anaerobe absolutely cannot tolerate oxygen
and will DIE if oxygen is present. A facultative aerobe does not require oxygen for metabolism but can use it if present. A microaerophile prefers lower
concentrations of oxygen. An aerotolerant anaerobe does not use oxygen but has mechanisms to break it down if present. An anaerobe lacks the enzymes needed
to metabolize oxygen. Understanding oxygen requirements is critical for culturing and identifying microorganisms.
6. A psychrophile is a microbe that:
A. Thrives at high temperatures above 45°C
B. Grows best at moderate temperatures (20–40°C), like humans and pathogens
C. Can grow and reproduce in cold temperatures, with an optimum of 15°C
D. Requires high salt concentrations to survive
CORRECT ANSWER C — Can grow and reproduce in cold temperatures, with an optimum of 15°C
RATIONALE A psychrophile is a microbe that can grow and reproduce in low/cold temperatures, with an optimal growth temperature of approximately 15°C. A mesophile
grows best at moderate temperatures (20–40°C) — humans and most human pathogens are mesophiles. A thermophile thrives at relatively high temperatures
above 45°C. A halophile is a salt-loving microbe that thrives in environments with high salt concentrations. Cardinal temperatures describe the range of
temperatures for the growth of a given microbial species: minimum, optimum, and maximum.
7. During which phase of the bacterial growth curve is the best time to treat an infection with antibiotics, and why?
A. Lag phase — cells are dormant and unaffected by antibiotics
B. Exponential (growth/log) phase — cells are actively multiplying and are most vulnerable to antibiotics
C. Stationary phase — population is in survival mode and resistant to treatment
D. Death phase — antibiotics are unnecessary because cells are already dying
CORRECT ANSWER B — Exponential (growth/log) phase — cells are actively multiplying and are most vulnerable to antibiotics
RATIONALE The exponential (growth/log) phase is the best time to treat with antibiotics because cells are actively multiplying, metabolically active, and most vulnerable to
antimicrobial agents that target cell processes like cell wall synthesis, protein synthesis, and DNA replication. The four phases are: (1) Lag phase — cells adjust after
inoculation, flat growth; (2) Exponential/Growth phase — maximum growth rate, cells multiply geometrically; (3) Stationary phase — cell death balances
multiplication, population stabilizes; (4) Death phase — death rate exceeds multiplication, population declines exponentially.
8. Enzymes function as biological catalysts by:
A. Increasing the activation energy required for a reaction
B. Lowering the activation energy, speeding up reactions without being consumed
C. Being permanently destroyed after each chemical reaction
D. Changing the equilibrium constant of the reaction
CORRECT ANSWER B — Lowering the activation energy, speeding up reactions without being consumed
RATIONALE Enzymes are proteins (and sometimes RNAs) that act as biological catalysts — they lower the activation energy of chemical reactions, making them occur faster
and more easily. Enzymes are neither used up nor permanently changed during the reaction. Cofactors are nonprotein metal molecules or ions required for proper
enzyme function. Coenzymes are organic cofactors (e.g., vitamins). Constitutive enzymes are always present at equal rates. Regulated enzymes are induced or
repressed based on substrate concentration. Competitive inhibition occurs when a molecule resembling the substrate occupies the active site. Denaturation is the
loss of protein structure and function due to heat, pH, or salt changes.
2 MAXE • 242 SOIB
★ ★
C College of Nursing & Health Professions
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
M I C R O B I A L N U T R I T I O N , M E TA B O L I S M , G R O W T H & A N T I M I C R O B I A L CO N T R O L
INSTITUTION Chamberlain University COURSE CODE BIOS 242
PROGRAM Bachelor of Science in Nursing (BSN) ACADEMIC YEAR
EXAM TITLE Examination 2 — Nutrition, Metabolism & Control TOTAL QUESTIONS 25 Questions
COURSE TITLE Fundamentals of Microbiology FORMAT Multiple Choice — Select the Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This examination covers microbial nutrition, metabolism, growth phases, control methods, and antimicrobial drugs.
▸ All content reflects BIOS 242 learning objectives and foundational microbiology for nursing practice.
▸ Correct answers and detailed rationales appear below each question for exam preparation purposes.
▸ Pay careful attention to oxygen requirements, enzyme function, and antibiotic mechanisms of action.
SECTION I — NUTRITION, METABOLISM, GROWTH, CONTROL & ANTIMICROBIAL DRUGS Questions 1 – 25
1. A photoautotroph derives its energy and carbon from which sources?
A. Energy from chemical compounds; carbon from organic matter
B. Energy from light rays; carbon from CO₂ in the air (inorganic source)
C. Energy from light; carbon from consuming other organisms
D. Energy from inorganic materials; carbon from rocks
CORRECT ANSWER B — Energy from light rays; carbon from CO₂ in the air (inorganic source)
RATIONALE A photoautotroph gains energy from light (through photosynthesis) and uses carbon dioxide (CO₂) from the air as its carbon source — an inorganic form of carbon.
Examples include photosynthetic organisms: algae, plants, and cyanobacteria. Photoautotrophs are the basis of most food webs because they produce organic
compounds from inorganic carbon. A chemoheterotroph (like humans) derives both energy and carbon from consumed organic food. A chemoautotroph gets
energy from chemical compounds and carbon from inorganic sources. A lithoautotroph gets energy from inorganic materials.
2. Humans are classified as chemoheterotrophs. What does this mean?
A. We gain energy from light and carbon from CO₂
B. We derive both energy and carbon from the organic food we consume
C. We produce our own food through photosynthesis
D. We gain energy from inorganic materials like rocks
CORRECT ANSWER B — We derive both energy and carbon from the organic food we consume
RATIONALE Chemoheterotrophs derive both their energy (from chemical energy in consumed food) and their carbon source (from the organic compounds in that food) from
external organic sources. Humans, all animals, fungi, and many bacteria are chemoheterotrophs — they are nutritionally dependent on other life forms. An
autotroph ("self-feeder") uses CO₂ as its carbon source and is NOT nutritionally dependent on other living things. A phototroph gains energy from light. A
chemotroph gains energy from chemical compounds. A heterotroph must obtain carbon in organic form.
3. Aerobic respiration differs from anaerobic respiration in that aerobic respiration:
A. Does not require any electron acceptors
B. Uses oxygen (O₂) as the final electron acceptor in the electron transport chain
C. Produces less ATP than fermentation
D. Occurs only in the cytoplasm without mitochondria
CORRECT ANSWER B — Uses oxygen (O₂) as the final electron acceptor in the electron transport chain
RATIONALE Aerobic respiration is the principal energy-yielding pathway in which the final electron acceptor in the electron transport chain is oxygen (O₂). It produces the
largest amount of ATP — approximately 36–38 ATP per glucose molecule. In contrast, anaerobic respiration does not use oxygen as the final electron acceptor;
instead, it uses other molecules (nitrate, sulfate). Fermentation is the incomplete oxidation of glucose without oxygen, produces only a small amount of ATP (2 ATP
from glycolysis), and uses organic compounds as terminal electron acceptors, resulting in products like alcohol or acid.
, 4. What is the difference between active transport and facilitated diffusion?
A. Both require ATP and transport against the concentration gradient
B. Active transport uses ATP to move substances against the concentration gradient; facilitated diffusion uses a carrier protein but does not require energy and moves
with the gradient
C. Facilitated diffusion requires ATP; active transport does not
D. Active transport only moves water; facilitated diffusion only moves glucose
CORRECT ANSWER B — Active transport uses ATP to move substances against the concentration gradient; facilitated diffusion uses a carrier protein but does not require
energy and moves with the gradient
RATIONALE Active transport requires ATP energy to transport substances against their concentration gradient (from low to high concentration). Facilitated diffusion uses a
specific carrier protein that binds to a molecule and changes shape to carry it across the membrane, but moves with the concentration gradient (high to low) and
does NOT require energy. Simple diffusion is the movement of molecules from higher to lower concentration without a carrier. Group translocation is a form of
active transport that chemically modifies the substance during transport. Osmosis is the movement of water across a selectively permeable membrane.
5. An organism that CANNOT grow or metabolize without oxygen is classified as a(n):
A. Obligate anaerobe — will die if oxygen is present
B. Facultative aerobe — does not require oxygen but can use it
C. Obligate aerobe — absolutely requires oxygen to grow and metabolize
D. Aerotolerant anaerobe — does not use oxygen but tolerates it
CORRECT ANSWER C — Obligate aerobe — absolutely requires oxygen to grow and metabolize
RATIONALE An obligate aerobe CANNOT grow or metabolize without oxygen — it has an absolute requirement for O₂. An obligate anaerobe absolutely cannot tolerate oxygen
and will DIE if oxygen is present. A facultative aerobe does not require oxygen for metabolism but can use it if present. A microaerophile prefers lower
concentrations of oxygen. An aerotolerant anaerobe does not use oxygen but has mechanisms to break it down if present. An anaerobe lacks the enzymes needed
to metabolize oxygen. Understanding oxygen requirements is critical for culturing and identifying microorganisms.
6. A psychrophile is a microbe that:
A. Thrives at high temperatures above 45°C
B. Grows best at moderate temperatures (20–40°C), like humans and pathogens
C. Can grow and reproduce in cold temperatures, with an optimum of 15°C
D. Requires high salt concentrations to survive
CORRECT ANSWER C — Can grow and reproduce in cold temperatures, with an optimum of 15°C
RATIONALE A psychrophile is a microbe that can grow and reproduce in low/cold temperatures, with an optimal growth temperature of approximately 15°C. A mesophile
grows best at moderate temperatures (20–40°C) — humans and most human pathogens are mesophiles. A thermophile thrives at relatively high temperatures
above 45°C. A halophile is a salt-loving microbe that thrives in environments with high salt concentrations. Cardinal temperatures describe the range of
temperatures for the growth of a given microbial species: minimum, optimum, and maximum.
7. During which phase of the bacterial growth curve is the best time to treat an infection with antibiotics, and why?
A. Lag phase — cells are dormant and unaffected by antibiotics
B. Exponential (growth/log) phase — cells are actively multiplying and are most vulnerable to antibiotics
C. Stationary phase — population is in survival mode and resistant to treatment
D. Death phase — antibiotics are unnecessary because cells are already dying
CORRECT ANSWER B — Exponential (growth/log) phase — cells are actively multiplying and are most vulnerable to antibiotics
RATIONALE The exponential (growth/log) phase is the best time to treat with antibiotics because cells are actively multiplying, metabolically active, and most vulnerable to
antimicrobial agents that target cell processes like cell wall synthesis, protein synthesis, and DNA replication. The four phases are: (1) Lag phase — cells adjust after
inoculation, flat growth; (2) Exponential/Growth phase — maximum growth rate, cells multiply geometrically; (3) Stationary phase — cell death balances
multiplication, population stabilizes; (4) Death phase — death rate exceeds multiplication, population declines exponentially.
8. Enzymes function as biological catalysts by:
A. Increasing the activation energy required for a reaction
B. Lowering the activation energy, speeding up reactions without being consumed
C. Being permanently destroyed after each chemical reaction
D. Changing the equilibrium constant of the reaction
CORRECT ANSWER B — Lowering the activation energy, speeding up reactions without being consumed
RATIONALE Enzymes are proteins (and sometimes RNAs) that act as biological catalysts — they lower the activation energy of chemical reactions, making them occur faster
and more easily. Enzymes are neither used up nor permanently changed during the reaction. Cofactors are nonprotein metal molecules or ions required for proper
enzyme function. Coenzymes are organic cofactors (e.g., vitamins). Constitutive enzymes are always present at equal rates. Regulated enzymes are induced or
repressed based on substrate concentration. Competitive inhibition occurs when a molecule resembling the substrate occupies the active site. Denaturation is the
loss of protein structure and function due to heat, pH, or salt changes.
