BIOD 101 MODULE 4 HIGH-LEVEL
BIOLOGY EXAM QUESTIONS &
VERIFIED ANSWERS (A+ GUARANTEE)
1. Which enzyme is responsible for the ‘first’ committed step of glycolysis, acting as a major
regulatory point?
A. Hexokinase
B. Aldolase
C. Pyruvate Kinase
D. Phosphofructokinase-1
Answer: D
Conceptual Explanation: Phosphofructokinase-1 (PFK-1) is the primary rate-limiting
enzyme of glycolysis, regulated by ATP and AMP levels.
2. In the mitochondrial electron transport chain, which complex does NOT pump protons
across the inner membrane?
A. Complex II
B. Complex I
C. Complex III
D. Complex IV
,Answer: A
Conceptual Explanation: Complex II (Succinate Dehydrogenase) receives electrons from
FADH2 but does not possess the energy to pump protons into the intermembrane space.
3. What is the precise role of oxygen in aerobic cellular respiration?
A. To donate electrons to the citric acid cycle
B. To facilitate the diffusion of ATP out of the mitochondria
C. To catalyze the conversion of glucose to pyruvate
D. To act as the final electron acceptor at the end of the ETC
Answer: D
Conceptual Explanation: Oxygen acts as the final electron acceptor, combining with
electrons and protons to form water, which maintains the flow of the electron transport
chain.
4. During the Calvin Cycle, how many molecules of ATP and NADPH are required to produce
one net molecule of G3P?
A. 3 ATP and 2 NADPH
B. 6 ATP and 6 NADPH
C. 18 ATP and 12 NADPH
D. 9 ATP and 6 NADPH
Answer: D
, Conceptual Explanation: One G3P molecule requires 3 turns of the cycle, consuming 9
ATP and 6 NADPH in total.
5. Which specific phase of the cell cycle involves the duplication of centrosomes?
A. G1 phase
B. G2 phase
C. S phase
D. M phase
Answer: C
Conceptual Explanation: Centrosome duplication occurs during the S phase, concurrently
with DNA replication.
6. In C4 plants, where is the enzyme Rubisco primarily located?
A. Bundle-sheath cells
B. Stomata
C. Mesophyll cells
D. Epidermal cells
Answer: A
Conceptual Explanation: In C4 plants, Rubisco is sequestered in the bundle-sheath cells to
minimize photorespiration by maintaining a high CO2 concentration.
BIOLOGY EXAM QUESTIONS &
VERIFIED ANSWERS (A+ GUARANTEE)
1. Which enzyme is responsible for the ‘first’ committed step of glycolysis, acting as a major
regulatory point?
A. Hexokinase
B. Aldolase
C. Pyruvate Kinase
D. Phosphofructokinase-1
Answer: D
Conceptual Explanation: Phosphofructokinase-1 (PFK-1) is the primary rate-limiting
enzyme of glycolysis, regulated by ATP and AMP levels.
2. In the mitochondrial electron transport chain, which complex does NOT pump protons
across the inner membrane?
A. Complex II
B. Complex I
C. Complex III
D. Complex IV
,Answer: A
Conceptual Explanation: Complex II (Succinate Dehydrogenase) receives electrons from
FADH2 but does not possess the energy to pump protons into the intermembrane space.
3. What is the precise role of oxygen in aerobic cellular respiration?
A. To donate electrons to the citric acid cycle
B. To facilitate the diffusion of ATP out of the mitochondria
C. To catalyze the conversion of glucose to pyruvate
D. To act as the final electron acceptor at the end of the ETC
Answer: D
Conceptual Explanation: Oxygen acts as the final electron acceptor, combining with
electrons and protons to form water, which maintains the flow of the electron transport
chain.
4. During the Calvin Cycle, how many molecules of ATP and NADPH are required to produce
one net molecule of G3P?
A. 3 ATP and 2 NADPH
B. 6 ATP and 6 NADPH
C. 18 ATP and 12 NADPH
D. 9 ATP and 6 NADPH
Answer: D
, Conceptual Explanation: One G3P molecule requires 3 turns of the cycle, consuming 9
ATP and 6 NADPH in total.
5. Which specific phase of the cell cycle involves the duplication of centrosomes?
A. G1 phase
B. G2 phase
C. S phase
D. M phase
Answer: C
Conceptual Explanation: Centrosome duplication occurs during the S phase, concurrently
with DNA replication.
6. In C4 plants, where is the enzyme Rubisco primarily located?
A. Bundle-sheath cells
B. Stomata
C. Mesophyll cells
D. Epidermal cells
Answer: A
Conceptual Explanation: In C4 plants, Rubisco is sequestered in the bundle-sheath cells to
minimize photorespiration by maintaining a high CO2 concentration.
