BIOS 242 EXAM 2 REVIEW LATEST –
344 REAL EXAM Q&A WITH
RATIONALES | FUNDAMENTALS OF
MICROBIOLOGY | CHAMBERLAIN |
GRADED A+
Section 1: Microbial Metabolism
1. The sum of all chemical reactions in a cell is called:
a) Anabolism
b) Catabolism
c) Metabolism
d) Glycolysis
Answer: c) Metabolism
Rationale: Metabolism encompasses all chemical reactions in a cell, including catabolic
reactions (breakdown of molecules to release energy) and anabolic reactions (synthesis
of cellular components using energy).
2. Which of the following is TRUE about catabolic reactions?
a) They require energy input
b) They release energy
Answer: b) They release energy
Rationale: Catabolic reactions break down complex molecules into simpler ones,
releasing the energy stored in chemical bonds. This energy is then used to drive
anabolic reactions or perform cellular work.
3. Which pathway is present in fermentation?
a) Glycolysis only
b) Krebs cycle only
c) Electron transport chain
d) Glycolysis and Krebs cycle
Answer: a) Glycolysis only
Rationale: Fermentation is an anaerobic process that uses only glycolysis to produce
ATP. It does not involve the Krebs cycle or an electron transport chain. The pyruvate
,produced in glycolysis is converted into fermentation end products like lactic acid or
ethanol.
4. The enzyme that synthesizes ATP during chemiosmosis is:
a) ATP synthase
b) Cytochrome c
c) NADH dehydrogenase
d) Coenzyme Q
Answer: a) ATP synthase
Rationale: ATP synthase is the enzyme that harnesses the proton motive force (a
gradient of protons across a membrane) to phosphorylate ADP to ATP during
chemiosmosis in oxidative phosphorylation and photophosphorylation.
5. Which of the following processes produces the most ATP per glucose
molecule?
a) Glycolysis
b) Fermentation
c) Aerobic respiration
d) Krebs cycle alone
Answer: c) Aerobic respiration
Rationale: Aerobic respiration yields up to 38 ATP per glucose (prokaryotes) or 36 ATP
(eukaryotes) because it fully oxidizes glucose to CO₂ and H₂O. Fermentation yields only
2 ATP per glucose, and glycolysis alone yields a net of 2 ATP.
Section 2: Microbial Nutrition and Growth
6. An organism that uses inorganic CO₂ as its carbon source and gains energy
from chemical compounds is classified as:
a) Photoautotroph
b) Photoheterotroph
c) Chemoautotroph
d) Chemoheterotroph
Answer: c) Chemoautotroph
Rationale: Chemoautotrophs use CO₂ as a carbon source and obtain energy from
chemical compounds (e.g., nitrifying bacteria). Photoautotrophs use light energy, and
photoheterotrophs use light energy and organic carbon sources.
7. What is the temperature range for the optimal rate of growth for a
mesophile?
a) 0-15°C
b) 20-40°C
,c) 45-80°C
d) Above 80°C
Answer: b) 20-40°C
Rationale: Mesophiles are organisms that grow best at moderate temperatures,
typically between 20°C and 40°C. Most human pathogens are mesophiles, as they are
adapted to the human body temperature of 37°C.
8. What does a halophile require for growth?
a) High hydrostatic pressure
b) High concentration of salt
c) Low pH
d) High temperature
Answer: b) High concentration of salt
Rationale: Halophiles are "salt-loving" microorganisms that require high
concentrations of salt (typically 9-25% NaCl) for growth. They are often found in
environments like the Dead Sea and salt flats.
9. An organism uses sunlight for energy and carbon dioxide as its carbon
source. What is it called?
a) Photoheterotroph
b) Chemoautotroph
c) Photoautotroph
d) Chemoheterotroph
Answer: c) Photoautotroph
Rationale: A photoautotroph uses light (photo-) as its energy source and carbon dioxide
(auto-) as its carbon source. Examples include plants, algae, and cyanobacteria.
10. A small molecule crosses the lipid bilayer directly from high to low
concentration. Which transport process is occurring?
a) Active transport
b) Facilitated diffusion
c) Simple diffusion
d) Group translocation
Answer: c) Simple diffusion
Rationale: Simple diffusion is the passive movement of molecules from an area of high
concentration to an area of low concentration directly through the lipid bilayer, without
the need for transport proteins or energy expenditure.
Section 3: Microbial Genetics
, 11. In Griffith's experiment, rough, non-virulent strains of Streptococcus
pneumoniae became smooth, virulent strains when mixed with heat-killed
smooth strain cells. This experiment demonstrates:
a) Transduction
b) Conjugation
c) Transformation
d) Mutation
Answer: c) Transformation
Rationale: Transformation is the process by which a bacterial cell takes up naked DNA
from its environment and incorporates it into its own genome. Griffith's experiment
was the first to demonstrate this phenomenon, showing that genetic material could be
transferred between bacteria.
12. What is the primary role of enzymes in microbial metabolism?
a) To increase the rate of chemical reactions
b) To provide energy for reactions
c) To act as a carbon source
d) To serve as genetic material
Answer: a) To increase the rate of chemical reactions
Rationale: Enzymes are biological catalysts that speed up the rate of chemical reactions
by lowering the activation energy required for the reaction to occur. They are not
consumed in the reaction and do not provide energy.
13. Which of the following is NOT a mechanism of horizontal gene transfer in
bacteria?
a) Transformation
b) Conjugation
c) Transduction
d) Binary fission
Answer: d) Binary fission
Rationale: Binary fission is a form of asexual reproduction, not horizontal gene transfer.
Horizontal gene transfer involves the movement of genetic material between
organisms other than by the transmission of DNA from parent to offspring.
Transformation, conjugation, and transduction are the three main mechanisms of
horizontal gene transfer.
Section 4: Control of Microbial Growth
14. What is disinfection?
a) The complete removal of all microorganisms, including endospores
b) The use of a physical process or chemical agent to destroy vegetative pathogens,
344 REAL EXAM Q&A WITH
RATIONALES | FUNDAMENTALS OF
MICROBIOLOGY | CHAMBERLAIN |
GRADED A+
Section 1: Microbial Metabolism
1. The sum of all chemical reactions in a cell is called:
a) Anabolism
b) Catabolism
c) Metabolism
d) Glycolysis
Answer: c) Metabolism
Rationale: Metabolism encompasses all chemical reactions in a cell, including catabolic
reactions (breakdown of molecules to release energy) and anabolic reactions (synthesis
of cellular components using energy).
2. Which of the following is TRUE about catabolic reactions?
a) They require energy input
b) They release energy
Answer: b) They release energy
Rationale: Catabolic reactions break down complex molecules into simpler ones,
releasing the energy stored in chemical bonds. This energy is then used to drive
anabolic reactions or perform cellular work.
3. Which pathway is present in fermentation?
a) Glycolysis only
b) Krebs cycle only
c) Electron transport chain
d) Glycolysis and Krebs cycle
Answer: a) Glycolysis only
Rationale: Fermentation is an anaerobic process that uses only glycolysis to produce
ATP. It does not involve the Krebs cycle or an electron transport chain. The pyruvate
,produced in glycolysis is converted into fermentation end products like lactic acid or
ethanol.
4. The enzyme that synthesizes ATP during chemiosmosis is:
a) ATP synthase
b) Cytochrome c
c) NADH dehydrogenase
d) Coenzyme Q
Answer: a) ATP synthase
Rationale: ATP synthase is the enzyme that harnesses the proton motive force (a
gradient of protons across a membrane) to phosphorylate ADP to ATP during
chemiosmosis in oxidative phosphorylation and photophosphorylation.
5. Which of the following processes produces the most ATP per glucose
molecule?
a) Glycolysis
b) Fermentation
c) Aerobic respiration
d) Krebs cycle alone
Answer: c) Aerobic respiration
Rationale: Aerobic respiration yields up to 38 ATP per glucose (prokaryotes) or 36 ATP
(eukaryotes) because it fully oxidizes glucose to CO₂ and H₂O. Fermentation yields only
2 ATP per glucose, and glycolysis alone yields a net of 2 ATP.
Section 2: Microbial Nutrition and Growth
6. An organism that uses inorganic CO₂ as its carbon source and gains energy
from chemical compounds is classified as:
a) Photoautotroph
b) Photoheterotroph
c) Chemoautotroph
d) Chemoheterotroph
Answer: c) Chemoautotroph
Rationale: Chemoautotrophs use CO₂ as a carbon source and obtain energy from
chemical compounds (e.g., nitrifying bacteria). Photoautotrophs use light energy, and
photoheterotrophs use light energy and organic carbon sources.
7. What is the temperature range for the optimal rate of growth for a
mesophile?
a) 0-15°C
b) 20-40°C
,c) 45-80°C
d) Above 80°C
Answer: b) 20-40°C
Rationale: Mesophiles are organisms that grow best at moderate temperatures,
typically between 20°C and 40°C. Most human pathogens are mesophiles, as they are
adapted to the human body temperature of 37°C.
8. What does a halophile require for growth?
a) High hydrostatic pressure
b) High concentration of salt
c) Low pH
d) High temperature
Answer: b) High concentration of salt
Rationale: Halophiles are "salt-loving" microorganisms that require high
concentrations of salt (typically 9-25% NaCl) for growth. They are often found in
environments like the Dead Sea and salt flats.
9. An organism uses sunlight for energy and carbon dioxide as its carbon
source. What is it called?
a) Photoheterotroph
b) Chemoautotroph
c) Photoautotroph
d) Chemoheterotroph
Answer: c) Photoautotroph
Rationale: A photoautotroph uses light (photo-) as its energy source and carbon dioxide
(auto-) as its carbon source. Examples include plants, algae, and cyanobacteria.
10. A small molecule crosses the lipid bilayer directly from high to low
concentration. Which transport process is occurring?
a) Active transport
b) Facilitated diffusion
c) Simple diffusion
d) Group translocation
Answer: c) Simple diffusion
Rationale: Simple diffusion is the passive movement of molecules from an area of high
concentration to an area of low concentration directly through the lipid bilayer, without
the need for transport proteins or energy expenditure.
Section 3: Microbial Genetics
, 11. In Griffith's experiment, rough, non-virulent strains of Streptococcus
pneumoniae became smooth, virulent strains when mixed with heat-killed
smooth strain cells. This experiment demonstrates:
a) Transduction
b) Conjugation
c) Transformation
d) Mutation
Answer: c) Transformation
Rationale: Transformation is the process by which a bacterial cell takes up naked DNA
from its environment and incorporates it into its own genome. Griffith's experiment
was the first to demonstrate this phenomenon, showing that genetic material could be
transferred between bacteria.
12. What is the primary role of enzymes in microbial metabolism?
a) To increase the rate of chemical reactions
b) To provide energy for reactions
c) To act as a carbon source
d) To serve as genetic material
Answer: a) To increase the rate of chemical reactions
Rationale: Enzymes are biological catalysts that speed up the rate of chemical reactions
by lowering the activation energy required for the reaction to occur. They are not
consumed in the reaction and do not provide energy.
13. Which of the following is NOT a mechanism of horizontal gene transfer in
bacteria?
a) Transformation
b) Conjugation
c) Transduction
d) Binary fission
Answer: d) Binary fission
Rationale: Binary fission is a form of asexual reproduction, not horizontal gene transfer.
Horizontal gene transfer involves the movement of genetic material between
organisms other than by the transmission of DNA from parent to offspring.
Transformation, conjugation, and transduction are the three main mechanisms of
horizontal gene transfer.
Section 4: Control of Microbial Growth
14. What is disinfection?
a) The complete removal of all microorganisms, including endospores
b) The use of a physical process or chemical agent to destroy vegetative pathogens,
