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 E TA B O L I S M , G R O W T H , CO N T R O L , D R U G R E S I STA N C E & I N F E C T I O N
INSTITUTION Chamberlain University COURSE CODE BIOS 242
PROGRAM Bachelor of Science in Nursing (BSN) ACADEMIC YEAR
EXAM TITLE Examination 2 — Fundamentals of Microbiology TOTAL QUESTIONS 25 Questions
COURSE TITLE Fundamentals of Microbiology FORMAT Multiple Choice / True-False — Select the Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This examination covers enzymes, metabolism, growth phases, microbial control, drug resistance, and infection stages.
▸ 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 enzyme regulation, drug resistance mechanisms, and biosafety levels.
SECTION I — ENZYMES, METABOLISM, GROWTH, CONTROL, RESISTANCE & EPIDEMIOLOGY Questions 1 – 25
1. A heterotroph is defined as an organism that:
A. Uses inorganic CO₂ as its carbon source (a self-feeder)
B. Must obtain its carbon in organic form — nutritionally dependent on other life forms
C. Gains energy from sunlight through photosynthesis
D. Gains energy from chemical compounds only
CORRECT ANSWER B — Must obtain its carbon in organic form — nutritionally dependent on other life forms
RATIONALE A heterotroph must obtain carbon in organic form — it is nutritionally dependent on other living things. Animals, fungi, and many bacteria are heterotrophs. An
autotroph uses inorganic CO₂ as its carbon source (self-feeder — e.g., plants). A phototroph gains energy from sunlight through photosynthesis. A chemotroph
gains energy from chemical compounds. These terms can be combined: photoautotrophs (light + CO₂), chemoheterotrophs (chemicals + organic carbon —
humans), chemoautotrophs (chemicals + CO₂ — methanogens).
2. The optimal growth temperature for a mesophile is:
A. 0–15°C — cold-loving organisms
B. 20–40°C — moderate temperature-loving organisms, includes most human pathogens
C. 45–80°C — heat-loving organisms
D. Above 100°C — extreme hyperthermophiles
CORRECT ANSWER B — 20–40°C — moderate temperature-loving organisms, includes most human pathogens
RATIONALE Mesophiles thrive at moderate temperatures with optimal growth between 20–40°C. Most human pathogens are mesophiles because body temperature (37°C) falls
within this range. Psychrophiles grow optimally at 0–15°C. Thermophiles grow optimally at 45–80°C. A barophile requires high hydrostatic pressure (e.g., deep-sea
microbes living at 1000x atmospheric pressure). A halophile requires high salt concentrations (9–25% NaCl). These environmental adaptations determine where
microorganisms can survive and cause infection.
3. Enzymes function as biological catalysts. Which statement about enzymes is TRUE?
A. Enzymes increase the activation energy required for reactions
B. Enzymes lower the activation energy, bind to substrates, and convert them into products
C. Enzymes are permanently consumed and destroyed during each reaction
D. Enzymes work only on inorganic substrates
CORRECT ANSWER B — Enzymes lower the activation energy, bind to substrates, and convert them into products
RATIONALE Enzymes are biological catalysts that increase the rate of chemical reactions by lowering the activation energy required. They act on reactant molecules called
substrates, bind them, and chemically change them into products. Enzymes are NOT consumed or destroyed during reactions. An apoenzyme is the protein
portion (sequence of amino acids). A holoenzyme requires both cofactors (inorganic elements — metal ions that activate enzymes) and coenzymes (organic
elements, most importantly vitamins). Cofactors help bring the active site and substrate close together and DO directly participate in chemical reactions.
Coenzymes remove chemical groups from one substrate and add them to another.
, 4. During the lag phase of the bacterial growth curve:
A. Cells multiply at their maximum rate and the curve increases geometrically
B. The population appears not to be growing — cells require adjustment, enlargement, and synthesis; they are not multiplying at maximum rate
C. Cell death equals cell multiplication and the population stabilizes
D. Cells die at an exponential rate due to depleted nutrients
CORRECT ANSWER B — The population appears not to be growing — cells require adjustment, enlargement, and synthesis; they are not multiplying at maximum rate
RATIONALE The lag phase is the flat period when the population appears not to grow. Reasons: (1) newly inoculated cells require a period of adjustment, enlargement, and
synthesis; (2) cells are not multiplying at maximum rate; (3) the population is so sparse/dilute that sampling misses them. The exponential growth/log phase
follows — the curve increases geometrically as long as adequate nutrients and favorable environment exist. Stationary phase: population enters survival mode;
rate of cell growth equals rate of cell death; decline caused by depleted nutrients and oxygen. Death phase: limiting factors intensify, cells die exponentially.
Antimicrobial agents rapidly accelerate the death phase.
5. True/False: Both competitive and noncompetitive inhibition have direct controls on the action of enzymes.
A. True
B. False
CORRECT ANSWER True
RATIONALE Both competitive and noncompetitive inhibition directly control enzyme activity. Competitive inhibition: a molecule resembling the substrate occupies the active
site, preventing substrate binding; the enzyme cannot act on the inhibitor and is shut down. Noncompetitive inhibition: enzymes have two binding sites — the
active site and a regulatory (allosteric) site. Inhibition is regulated by molecules binding to the regulatory site, changing the enzyme's shape so the active site no
longer functions. These two mechanisms are fundamental to understanding drug action — many pharmaceuticals work through enzyme inhibition.
6. During the complete aerobic oxidation of glucose, where is the majority of NADH created?
A. Glycolysis — produces 2 NADH
B. Krebs Cycle — produces 6 NADH, the majority
C. Electron Transport Chain — produces 34 ATP but no NADH
D. Fermentation — produces NADH as a byproduct
CORRECT ANSWER B — Krebs Cycle — produces 6 NADH, the majority
RATIONALE The Krebs Cycle (Citric Acid Cycle) produces the majority of NADH — 6 NADH per glucose (3 per pyruvate). Glycolysis produces 2 NADH. The Electron Transport
Chain uses NADH and FADH₂ to produce 34 ATP but does not itself produce NADH. ATP is the source of energy use and storage in cells. The breakdown of all three
macromolecules (carbohydrates, proteins, and fats) converges at the Krebs Cycle with the production of acetyl-CoA. The Krebs Cycle is therefore central to
metabolism — it is amphibolic, serving both catabolic and anabolic pathways.
7. Which pathways are present in aerobic respiration, anaerobic respiration, and fermentation?
A. Aerobic: Glycolysis only; Anaerobic: Glycolysis only; Fermentation: All three pathways
B. Aerobic: Glycolysis, Krebs Cycle, ETC; Anaerobic: Glycolysis, Krebs Cycle, ETC; Fermentation: Glycolysis only
C. All three use identical pathways with no differences
D. Aerobic: ETC only; Anaerobic: Krebs only; Fermentation: Glycolysis and ETC
CORRECT ANSWER B — Aerobic: Glycolysis, Krebs Cycle, ETC; Anaerobic: Glycolysis, Krebs Cycle, ETC; Fermentation: Glycolysis only
RATIONALE Both aerobic and anaerobic respiration use all three pathways: Glycolysis, Krebs Cycle, and Electron Transport Chain. The key difference is the final electron
acceptor — O₂ in aerobic (yielding 36–38 ATP, 6 CO₂, 6 H₂O) vs. inorganic molecules like nitrate in anaerobic (yielding 2–36 ATP). Fermentation uses ONLY Glycolysis
(producing 2 ATP, NAD, acids/alcohols, and CO₂). In eukaryotes: glycolysis and fermentation occur in cytosol, Krebs Cycle in mitochondria, ETC at inner
mitochondrial membrane. In prokaryotes: Krebs Cycle and fermentation occur in cytoplasm, ETC at cytoplasmic membrane.
8. Sterilization differs from disinfection in that sterilization:
A. Destroys vegetative pathogens only, not endospores, on inanimate objects
B. Destroys ALL microbial life on inanimate objects, including endospores
C. Removes pathogens from living tissue only
D. Disinfects by mechanical scrubbing to reduce contamination
CORRECT ANSWER B — Destroys ALL microbial life on inanimate objects, including endospores
RATIONALE Sterilization destroys ALL microbial life including endospores on inanimate objects (autoclave: 15 psi, 121°C). Disinfection uses physical or chemical agents to
destroy vegetative pathogens but NOT endospores on inanimate objects. Antisepsis/degermation destroys vegetative pathogens (not endospores) on living
(animate) tissue. Decontamination is mechanical scrubbing to reduce contamination on both animate and inanimate objects. A bactericide kills bacteria except
endospores. A bacteriostatic agent prevents reproduction without killing. Pasteurization removes Coxiella and Mycobacterium but leaves endospores, lactobacilli,
micrococci, and yeast.
9. Halogens (chlorine, iodine, fluorine, bromine) are important in chemical microbial control because they are:
A. Only effective against Gram-positive bacteria
B. Microbicidal and sporicidal, and are active ingredients in approximately one-third of all antimicrobial chemicals
C. Used exclusively for sterilization of surgical instruments
D. Ineffective against viruses and fungi
CORRECT ANSWER B — Microbicidal and sporicidal, and are active ingredients in approximately one-third of all antimicrobial chemicals
RATIONALE Halogens (chlorine, iodine, fluorine, bromine) are both microbicidal (kill microbes) and sporicidal (kill spores) with longer exposure. They are active ingredients in
approximately one-third of all antimicrobial chemicals, making them among the most important chemical control agents. Chlorine is used for water disinfection;
iodine is used as a skin antiseptic (Betadine). They work by oxidizing proteins and other cellular components. Their broad-spectrum activity and low cost make
them essential in healthcare, food service, and water treatment settings.
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 E TA B O L I S M , G R O W T H , CO N T R O L , D R U G R E S I STA N C E & I N F E C T I O N
INSTITUTION Chamberlain University COURSE CODE BIOS 242
PROGRAM Bachelor of Science in Nursing (BSN) ACADEMIC YEAR
EXAM TITLE Examination 2 — Fundamentals of Microbiology TOTAL QUESTIONS 25 Questions
COURSE TITLE Fundamentals of Microbiology FORMAT Multiple Choice / True-False — Select the Single Best Answer
EXAMINATION INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This examination covers enzymes, metabolism, growth phases, microbial control, drug resistance, and infection stages.
▸ 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 enzyme regulation, drug resistance mechanisms, and biosafety levels.
SECTION I — ENZYMES, METABOLISM, GROWTH, CONTROL, RESISTANCE & EPIDEMIOLOGY Questions 1 – 25
1. A heterotroph is defined as an organism that:
A. Uses inorganic CO₂ as its carbon source (a self-feeder)
B. Must obtain its carbon in organic form — nutritionally dependent on other life forms
C. Gains energy from sunlight through photosynthesis
D. Gains energy from chemical compounds only
CORRECT ANSWER B — Must obtain its carbon in organic form — nutritionally dependent on other life forms
RATIONALE A heterotroph must obtain carbon in organic form — it is nutritionally dependent on other living things. Animals, fungi, and many bacteria are heterotrophs. An
autotroph uses inorganic CO₂ as its carbon source (self-feeder — e.g., plants). A phototroph gains energy from sunlight through photosynthesis. A chemotroph
gains energy from chemical compounds. These terms can be combined: photoautotrophs (light + CO₂), chemoheterotrophs (chemicals + organic carbon —
humans), chemoautotrophs (chemicals + CO₂ — methanogens).
2. The optimal growth temperature for a mesophile is:
A. 0–15°C — cold-loving organisms
B. 20–40°C — moderate temperature-loving organisms, includes most human pathogens
C. 45–80°C — heat-loving organisms
D. Above 100°C — extreme hyperthermophiles
CORRECT ANSWER B — 20–40°C — moderate temperature-loving organisms, includes most human pathogens
RATIONALE Mesophiles thrive at moderate temperatures with optimal growth between 20–40°C. Most human pathogens are mesophiles because body temperature (37°C) falls
within this range. Psychrophiles grow optimally at 0–15°C. Thermophiles grow optimally at 45–80°C. A barophile requires high hydrostatic pressure (e.g., deep-sea
microbes living at 1000x atmospheric pressure). A halophile requires high salt concentrations (9–25% NaCl). These environmental adaptations determine where
microorganisms can survive and cause infection.
3. Enzymes function as biological catalysts. Which statement about enzymes is TRUE?
A. Enzymes increase the activation energy required for reactions
B. Enzymes lower the activation energy, bind to substrates, and convert them into products
C. Enzymes are permanently consumed and destroyed during each reaction
D. Enzymes work only on inorganic substrates
CORRECT ANSWER B — Enzymes lower the activation energy, bind to substrates, and convert them into products
RATIONALE Enzymes are biological catalysts that increase the rate of chemical reactions by lowering the activation energy required. They act on reactant molecules called
substrates, bind them, and chemically change them into products. Enzymes are NOT consumed or destroyed during reactions. An apoenzyme is the protein
portion (sequence of amino acids). A holoenzyme requires both cofactors (inorganic elements — metal ions that activate enzymes) and coenzymes (organic
elements, most importantly vitamins). Cofactors help bring the active site and substrate close together and DO directly participate in chemical reactions.
Coenzymes remove chemical groups from one substrate and add them to another.
, 4. During the lag phase of the bacterial growth curve:
A. Cells multiply at their maximum rate and the curve increases geometrically
B. The population appears not to be growing — cells require adjustment, enlargement, and synthesis; they are not multiplying at maximum rate
C. Cell death equals cell multiplication and the population stabilizes
D. Cells die at an exponential rate due to depleted nutrients
CORRECT ANSWER B — The population appears not to be growing — cells require adjustment, enlargement, and synthesis; they are not multiplying at maximum rate
RATIONALE The lag phase is the flat period when the population appears not to grow. Reasons: (1) newly inoculated cells require a period of adjustment, enlargement, and
synthesis; (2) cells are not multiplying at maximum rate; (3) the population is so sparse/dilute that sampling misses them. The exponential growth/log phase
follows — the curve increases geometrically as long as adequate nutrients and favorable environment exist. Stationary phase: population enters survival mode;
rate of cell growth equals rate of cell death; decline caused by depleted nutrients and oxygen. Death phase: limiting factors intensify, cells die exponentially.
Antimicrobial agents rapidly accelerate the death phase.
5. True/False: Both competitive and noncompetitive inhibition have direct controls on the action of enzymes.
A. True
B. False
CORRECT ANSWER True
RATIONALE Both competitive and noncompetitive inhibition directly control enzyme activity. Competitive inhibition: a molecule resembling the substrate occupies the active
site, preventing substrate binding; the enzyme cannot act on the inhibitor and is shut down. Noncompetitive inhibition: enzymes have two binding sites — the
active site and a regulatory (allosteric) site. Inhibition is regulated by molecules binding to the regulatory site, changing the enzyme's shape so the active site no
longer functions. These two mechanisms are fundamental to understanding drug action — many pharmaceuticals work through enzyme inhibition.
6. During the complete aerobic oxidation of glucose, where is the majority of NADH created?
A. Glycolysis — produces 2 NADH
B. Krebs Cycle — produces 6 NADH, the majority
C. Electron Transport Chain — produces 34 ATP but no NADH
D. Fermentation — produces NADH as a byproduct
CORRECT ANSWER B — Krebs Cycle — produces 6 NADH, the majority
RATIONALE The Krebs Cycle (Citric Acid Cycle) produces the majority of NADH — 6 NADH per glucose (3 per pyruvate). Glycolysis produces 2 NADH. The Electron Transport
Chain uses NADH and FADH₂ to produce 34 ATP but does not itself produce NADH. ATP is the source of energy use and storage in cells. The breakdown of all three
macromolecules (carbohydrates, proteins, and fats) converges at the Krebs Cycle with the production of acetyl-CoA. The Krebs Cycle is therefore central to
metabolism — it is amphibolic, serving both catabolic and anabolic pathways.
7. Which pathways are present in aerobic respiration, anaerobic respiration, and fermentation?
A. Aerobic: Glycolysis only; Anaerobic: Glycolysis only; Fermentation: All three pathways
B. Aerobic: Glycolysis, Krebs Cycle, ETC; Anaerobic: Glycolysis, Krebs Cycle, ETC; Fermentation: Glycolysis only
C. All three use identical pathways with no differences
D. Aerobic: ETC only; Anaerobic: Krebs only; Fermentation: Glycolysis and ETC
CORRECT ANSWER B — Aerobic: Glycolysis, Krebs Cycle, ETC; Anaerobic: Glycolysis, Krebs Cycle, ETC; Fermentation: Glycolysis only
RATIONALE Both aerobic and anaerobic respiration use all three pathways: Glycolysis, Krebs Cycle, and Electron Transport Chain. The key difference is the final electron
acceptor — O₂ in aerobic (yielding 36–38 ATP, 6 CO₂, 6 H₂O) vs. inorganic molecules like nitrate in anaerobic (yielding 2–36 ATP). Fermentation uses ONLY Glycolysis
(producing 2 ATP, NAD, acids/alcohols, and CO₂). In eukaryotes: glycolysis and fermentation occur in cytosol, Krebs Cycle in mitochondria, ETC at inner
mitochondrial membrane. In prokaryotes: Krebs Cycle and fermentation occur in cytoplasm, ETC at cytoplasmic membrane.
8. Sterilization differs from disinfection in that sterilization:
A. Destroys vegetative pathogens only, not endospores, on inanimate objects
B. Destroys ALL microbial life on inanimate objects, including endospores
C. Removes pathogens from living tissue only
D. Disinfects by mechanical scrubbing to reduce contamination
CORRECT ANSWER B — Destroys ALL microbial life on inanimate objects, including endospores
RATIONALE Sterilization destroys ALL microbial life including endospores on inanimate objects (autoclave: 15 psi, 121°C). Disinfection uses physical or chemical agents to
destroy vegetative pathogens but NOT endospores on inanimate objects. Antisepsis/degermation destroys vegetative pathogens (not endospores) on living
(animate) tissue. Decontamination is mechanical scrubbing to reduce contamination on both animate and inanimate objects. A bactericide kills bacteria except
endospores. A bacteriostatic agent prevents reproduction without killing. Pasteurization removes Coxiella and Mycobacterium but leaves endospores, lactobacilli,
micrococci, and yeast.
9. Halogens (chlorine, iodine, fluorine, bromine) are important in chemical microbial control because they are:
A. Only effective against Gram-positive bacteria
B. Microbicidal and sporicidal, and are active ingredients in approximately one-third of all antimicrobial chemicals
C. Used exclusively for sterilization of surgical instruments
D. Ineffective against viruses and fungi
CORRECT ANSWER B — Microbicidal and sporicidal, and are active ingredients in approximately one-third of all antimicrobial chemicals
RATIONALE Halogens (chlorine, iodine, fluorine, bromine) are both microbicidal (kill microbes) and sporicidal (kill spores) with longer exposure. They are active ingredients in
approximately one-third of all antimicrobial chemicals, making them among the most important chemical control agents. Chlorine is used for water disinfection;
iodine is used as a skin antiseptic (Betadine). They work by oxidizing proteins and other cellular components. Their broad-spectrum activity and low cost make
them essential in healthcare, food service, and water treatment settings.
