JERSEY COLLEGE MICROBIOLOGY
FINAL EXAM (2026) QUESTIONS AND
ANSWERS
1. Which component of the Gram-negative cell wall is responsible for its toxic properties
when the cell undergoes lysis?
A. Teichoic acids
B. Peptidoglycan interbridges
C. Lipid A of the Lipopolysaccharide layer
D. Periplasmic binding proteins
Answer: C
Conceptual Explanation: Lipid A, located within the outer membrane of Gram-negative
bacteria, acts as an endotoxin, triggering severe immune responses like fever and shock
when released.
2. In the process of oxidative phosphorylation, what is the direct role of the Proton Motive
Force (PMF)?
A. To reduce NAD+ to NADH
,B. To pump protons against their concentration gradient
C. To act as the final electron acceptor in the chain
D. To drive the rotation of ATP synthase to generate ATP
Answer: D
Conceptual Explanation: The PMF creates an electrochemical gradient; as protons flow
back into the matrix through ATP synthase, the energy is used to phosphorylate ADP into
ATP.
3. During DNA replication in E. coli, which enzyme is responsible for removing RNA primers
and replacing them with DNA nucleotides?
A. DNA Polymerase III
B. DNA Ligase
C. Helicase
D. DNA Polymerase I
Answer: D
Conceptual Explanation: DNA Polymerase I has 5’ to 3’ exonuclease activity, allowing it to
remove RNA primers and replace them with DNA, whereas DNA Polymerase III is the
primary replicase.
4. Which of the following describes a ‘missense mutation’?
A. A mutation that results in a premature stop codon
, B. A mutation that does not change the resulting amino acid sequence
C. A mutation that changes a codon to code for a different amino acid
D. A mutation caused by the insertion of a single nucleotide shifting the reading frame
Answer: C
Conceptual Explanation: A missense mutation involves a single nucleotide change that
results in the substitution of one amino acid for another in the final protein.
5. What is the function of the Sigma factor in bacterial transcription?
A. To recognize and bind to the specific promoter sequence of DNA
B. To catalyze the formation of phosphodiester bonds
C. To terminate the transcription process
D. To proofread the newly synthesized RNA strand
Answer: A
Conceptual Explanation: The Sigma factor is a subunit of RNA polymerase that ensures
the enzyme binds specifically to promoter regions to initiate transcription.
6. Which metabolic pathway produces the highest amount of reduced NADH per molecule of
glucose?
A. Glycolysis
B. Fermentation
FINAL EXAM (2026) QUESTIONS AND
ANSWERS
1. Which component of the Gram-negative cell wall is responsible for its toxic properties
when the cell undergoes lysis?
A. Teichoic acids
B. Peptidoglycan interbridges
C. Lipid A of the Lipopolysaccharide layer
D. Periplasmic binding proteins
Answer: C
Conceptual Explanation: Lipid A, located within the outer membrane of Gram-negative
bacteria, acts as an endotoxin, triggering severe immune responses like fever and shock
when released.
2. In the process of oxidative phosphorylation, what is the direct role of the Proton Motive
Force (PMF)?
A. To reduce NAD+ to NADH
,B. To pump protons against their concentration gradient
C. To act as the final electron acceptor in the chain
D. To drive the rotation of ATP synthase to generate ATP
Answer: D
Conceptual Explanation: The PMF creates an electrochemical gradient; as protons flow
back into the matrix through ATP synthase, the energy is used to phosphorylate ADP into
ATP.
3. During DNA replication in E. coli, which enzyme is responsible for removing RNA primers
and replacing them with DNA nucleotides?
A. DNA Polymerase III
B. DNA Ligase
C. Helicase
D. DNA Polymerase I
Answer: D
Conceptual Explanation: DNA Polymerase I has 5’ to 3’ exonuclease activity, allowing it to
remove RNA primers and replace them with DNA, whereas DNA Polymerase III is the
primary replicase.
4. Which of the following describes a ‘missense mutation’?
A. A mutation that results in a premature stop codon
, B. A mutation that does not change the resulting amino acid sequence
C. A mutation that changes a codon to code for a different amino acid
D. A mutation caused by the insertion of a single nucleotide shifting the reading frame
Answer: C
Conceptual Explanation: A missense mutation involves a single nucleotide change that
results in the substitution of one amino acid for another in the final protein.
5. What is the function of the Sigma factor in bacterial transcription?
A. To recognize and bind to the specific promoter sequence of DNA
B. To catalyze the formation of phosphodiester bonds
C. To terminate the transcription process
D. To proofread the newly synthesized RNA strand
Answer: A
Conceptual Explanation: The Sigma factor is a subunit of RNA polymerase that ensures
the enzyme binds specifically to promoter regions to initiate transcription.
6. Which metabolic pathway produces the highest amount of reduced NADH per molecule of
glucose?
A. Glycolysis
B. Fermentation
