BIO 250 Exam 2 V2 | BIO 250 Microbiology | Actual
Q&A with Rationale (BIO250 Exam 2) |
StraighterLine
1. During the process of glycolysis, what is the net gain of ATP molecules produced per single
molecule of glucose?
A. 4 ATP
B. 2 ATP
C. 36 ATP
D. 0 ATP
Correct Answer: B
Explanation: Glycolysis initially requires the investment of two ATP molecules to
phosphorylate glucose. Although four ATP molecules are generated through substrate-level
phosphorylation, the net yield is only two. This process occurs in the cytosol of both
prokaryotic and eukaryotic cells.
2. Select all of the following enzymes that are directly involved in the process of DNA
replication in bacteria:
A. DNA Polymerase III
B. Helicase
C. Primase
,D. RNA Polymerase
E. DNA Ligase
F. Reverse Transcriptase
Correct Answer: A, B, C, E
Explanation: DNA replication requires a suite of specialized enzymes to unwind and
synthesize new strands. Helicase opens the double helix, while primase provides the
necessary RNA primers for synthesis. DNA Polymerase III performs the bulk of synthesis,
and DNA ligase seals nicks in the phosphate backbone, whereas RNA polymerase is used
for transcription.
3. Which phase of the bacterial growth curve is characterized by a period where the rate of
cell division equals the rate of cell death?
A. Lag phase
B. Log phase
C. Stationary phase
D. Death phase
Correct Answer: C
Explanation: The stationary phase occurs when essential nutrients are depleted and
metabolic waste products accumulate. During this stage, the total number of viable cells
, remains constant because the growth rate slows to match the death rate. This phase
follows the exponential log phase and precedes the decline phase.
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 amino acid sequence.
C. A mutation that results in a different amino acid being incorporated into the protein.
D. A mutation caused by the insertion of a transposon.
Correct Answer: C
Explanation: A missense mutation is a point mutation where a single nucleotide change
results in a codon that codes for a different amino acid. This can alter the protein’s function
depending on the chemical properties of the new amino acid. It differs from a nonsense
mutation, which creates a stop codon and truncates the protein.
5. In aerobic respiration, what is the final electron acceptor in the electron transport chain?
A. Nitrate
B. Pyruvate
C. Oxygen
D. NAD+
Correct Answer: C
Q&A with Rationale (BIO250 Exam 2) |
StraighterLine
1. During the process of glycolysis, what is the net gain of ATP molecules produced per single
molecule of glucose?
A. 4 ATP
B. 2 ATP
C. 36 ATP
D. 0 ATP
Correct Answer: B
Explanation: Glycolysis initially requires the investment of two ATP molecules to
phosphorylate glucose. Although four ATP molecules are generated through substrate-level
phosphorylation, the net yield is only two. This process occurs in the cytosol of both
prokaryotic and eukaryotic cells.
2. Select all of the following enzymes that are directly involved in the process of DNA
replication in bacteria:
A. DNA Polymerase III
B. Helicase
C. Primase
,D. RNA Polymerase
E. DNA Ligase
F. Reverse Transcriptase
Correct Answer: A, B, C, E
Explanation: DNA replication requires a suite of specialized enzymes to unwind and
synthesize new strands. Helicase opens the double helix, while primase provides the
necessary RNA primers for synthesis. DNA Polymerase III performs the bulk of synthesis,
and DNA ligase seals nicks in the phosphate backbone, whereas RNA polymerase is used
for transcription.
3. Which phase of the bacterial growth curve is characterized by a period where the rate of
cell division equals the rate of cell death?
A. Lag phase
B. Log phase
C. Stationary phase
D. Death phase
Correct Answer: C
Explanation: The stationary phase occurs when essential nutrients are depleted and
metabolic waste products accumulate. During this stage, the total number of viable cells
, remains constant because the growth rate slows to match the death rate. This phase
follows the exponential log phase and precedes the decline phase.
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 amino acid sequence.
C. A mutation that results in a different amino acid being incorporated into the protein.
D. A mutation caused by the insertion of a transposon.
Correct Answer: C
Explanation: A missense mutation is a point mutation where a single nucleotide change
results in a codon that codes for a different amino acid. This can alter the protein’s function
depending on the chemical properties of the new amino acid. It differs from a nonsense
mutation, which creates a stop codon and truncates the protein.
5. In aerobic respiration, what is the final electron acceptor in the electron transport chain?
A. Nitrate
B. Pyruvate
C. Oxygen
D. NAD+
Correct Answer: C
