1. What is the end product of glycolysis?
A. Glucose
B. ATP and NADH
C. Pyruvate
D. Oxygen
Answer: C) Pyruvate
Rationale: Glycolysis breaks down glucose into two molecules of
pyruvate, producing ATP and NADH as intermediates.
2. Which of the following is true about enzymes?
A. Enzymes increase the activation energy of reactions.
B. Enzymes are consumed during reactions.
C. Enzymes can be reused after catalyzing a reaction.
D. Enzymes are always proteins.
Answer: C) Enzymes can be reused after catalyzing a reaction.
Rationale: Enzymes are not consumed in reactions; they can catalyze
multiple reactions. They lower the activation energy required for
reactions to proceed.
3. Which of the following is true about DNA replication?
,A. It occurs during the G1 phase of the cell cycle.
B. It is a semi-conservative process.
C. It occurs during the G2 phase of the cell cycle.
D. It requires no enzymes to catalyze the reaction.
Answer: B) It is a semi-conservative process.
Rationale: In DNA replication, each new DNA molecule consists of one
original strand and one newly synthesized strand, making it semi-
conservative.
4. In which organelle does photosynthesis occur?
A. Mitochondria
B. Chloroplast
C. Nucleus
D. Ribosome
Answer: B) Chloroplast
Rationale: Chloroplasts contain chlorophyll and are the sites of
photosynthesis in plant cells and some algae.
5. During which stage of cellular respiration is the majority of ATP
produced?
A. Glycolysis
B. Krebs cycle
C. Electron transport chain
, D. Fermentation
Answer: C) Electron transport chain
Rationale: The majority of ATP in cellular respiration is produced in
the electron transport chain through oxidative phosphorylation.
6. What is the main purpose of the Krebs cycle?
A. To produce glucose
B. To generate ATP and electron carriers for the electron transport
chain
C. To produce oxygen
D. To synthesize proteins
Answer: B) To generate ATP and electron carriers for the electron
transport chain
Rationale: The Krebs cycle (citric acid cycle) generates high-energy
electron carriers (NADH, FADH2) and a small amount of ATP, which
are used in the electron transport chain to produce large amounts of
ATP.
7. What is the primary function of the mitochondria in eukaryotic cells?
A. Protein synthesis
B. Cellular respiration
C. DNA replication
D. Photosynthesis
A. Glucose
B. ATP and NADH
C. Pyruvate
D. Oxygen
Answer: C) Pyruvate
Rationale: Glycolysis breaks down glucose into two molecules of
pyruvate, producing ATP and NADH as intermediates.
2. Which of the following is true about enzymes?
A. Enzymes increase the activation energy of reactions.
B. Enzymes are consumed during reactions.
C. Enzymes can be reused after catalyzing a reaction.
D. Enzymes are always proteins.
Answer: C) Enzymes can be reused after catalyzing a reaction.
Rationale: Enzymes are not consumed in reactions; they can catalyze
multiple reactions. They lower the activation energy required for
reactions to proceed.
3. Which of the following is true about DNA replication?
,A. It occurs during the G1 phase of the cell cycle.
B. It is a semi-conservative process.
C. It occurs during the G2 phase of the cell cycle.
D. It requires no enzymes to catalyze the reaction.
Answer: B) It is a semi-conservative process.
Rationale: In DNA replication, each new DNA molecule consists of one
original strand and one newly synthesized strand, making it semi-
conservative.
4. In which organelle does photosynthesis occur?
A. Mitochondria
B. Chloroplast
C. Nucleus
D. Ribosome
Answer: B) Chloroplast
Rationale: Chloroplasts contain chlorophyll and are the sites of
photosynthesis in plant cells and some algae.
5. During which stage of cellular respiration is the majority of ATP
produced?
A. Glycolysis
B. Krebs cycle
C. Electron transport chain
, D. Fermentation
Answer: C) Electron transport chain
Rationale: The majority of ATP in cellular respiration is produced in
the electron transport chain through oxidative phosphorylation.
6. What is the main purpose of the Krebs cycle?
A. To produce glucose
B. To generate ATP and electron carriers for the electron transport
chain
C. To produce oxygen
D. To synthesize proteins
Answer: B) To generate ATP and electron carriers for the electron
transport chain
Rationale: The Krebs cycle (citric acid cycle) generates high-energy
electron carriers (NADH, FADH2) and a small amount of ATP, which
are used in the electron transport chain to produce large amounts of
ATP.
7. What is the primary function of the mitochondria in eukaryotic cells?
A. Protein synthesis
B. Cellular respiration
C. DNA replication
D. Photosynthesis
