,BIOD 101 Module 3 | Practice Q&A | 2026/2027 | Biology | Portage
Learning | 100% PASS
1. True or False: Catabolism refers to the sum of all synthetic energy-
requiring biochemical reactions.
A) True
B) False
Correct Answer: False
Rationale: Catabolism refers to the breakdown of larger molecules into
smaller subunits, releasing useful energy. Anabolism refers to the sum of all
synthetic energy-requiring biochemical reactions. This is a fundamental
distinction in metabolism.
2. Which of the following chemical reactions requires energy and occurs
when two or more monomers are joined together, resulting in the loss of a
water molecule?
A) Hydrolysis reaction
B) Dehydration condensation reaction
C) Oxidation-reduction reaction
D) Substitution reaction
Correct Answer: Dehydration condensation reaction
Rationale: A dehydration condensation reaction joins monomers together,
releasing a water molecule and requiring energy. Hydrolysis is the opposite—
breaking bonds using water. This is a key concept in polymer formation.
3. What is the purpose of the citric acid cycle (Krebs cycle)?
A) Produces glucose from pyruvate
,B) Generates high-energy molecules (NADH and FADH₂) that will be later
used to generate ATP in the electron transport chain
C) Directly produces the majority of ATP
D) Converts oxygen to carbon dioxide
Correct Answer: Generates high-energy molecules (NADH and FADH₂) that
will be later used to generate ATP in the electron transport chain
Rationale: The citric acid cycle generates high-energy molecules (NADH and
FADH₂) that will be later used to generate ATP in the electron transport chain.
It does not directly produce the majority of ATP.
4. The electron transport chain directly produces ATP.
A) True
B) False
Correct Answer: False
Rationale: The ETC does not directly produce any ATP. However, establishing
a proton gradient across the mitochondrial membrane will lead to the
production of ATP via ATP synthase. ATP is produced through chemiosmosis,
not directly by the ETC.
5. What is the role of ATP synthase in the electron transport chain?
A) To pump protons across the membrane
B) To generate ATP through chemiosmosis
C) To transfer electrons to oxygen
D) To break down glucose
, Correct Answer: To generate ATP through chemiosmosis
Rationale: ATP synthase is responsible for generating ATP through
chemiosmosis. Chemiosmosis is an energy-coupling process which harnesses
the energy that exists within the proton ion gradient and uses it to drive ATP
synthesis.
6. _______ respiration involves the consumption of oxygen, while _______
respiration can proceed in the absence of oxygen.
A) Aerobic; anaerobic
B) Anaerobic; aerobic
C) Cellular; fermentation
D) Oxidative; substrate-level
Correct Answer: Aerobic; anaerobic
Rationale: Aerobic respiration involves the consumption of oxygen, while
anaerobic respiration can proceed in the absence of oxygen. This is a
fundamental distinction in cellular respiration.
7. The first step of the citric acid cycle is a preparation phase sometimes
called:
A) Glycolysis
B) Pyruvate oxidation
C) Fermentation
D) Oxidative phosphorylation
Correct Answer: Pyruvate oxidation
Learning | 100% PASS
1. True or False: Catabolism refers to the sum of all synthetic energy-
requiring biochemical reactions.
A) True
B) False
Correct Answer: False
Rationale: Catabolism refers to the breakdown of larger molecules into
smaller subunits, releasing useful energy. Anabolism refers to the sum of all
synthetic energy-requiring biochemical reactions. This is a fundamental
distinction in metabolism.
2. Which of the following chemical reactions requires energy and occurs
when two or more monomers are joined together, resulting in the loss of a
water molecule?
A) Hydrolysis reaction
B) Dehydration condensation reaction
C) Oxidation-reduction reaction
D) Substitution reaction
Correct Answer: Dehydration condensation reaction
Rationale: A dehydration condensation reaction joins monomers together,
releasing a water molecule and requiring energy. Hydrolysis is the opposite—
breaking bonds using water. This is a key concept in polymer formation.
3. What is the purpose of the citric acid cycle (Krebs cycle)?
A) Produces glucose from pyruvate
,B) Generates high-energy molecules (NADH and FADH₂) that will be later
used to generate ATP in the electron transport chain
C) Directly produces the majority of ATP
D) Converts oxygen to carbon dioxide
Correct Answer: Generates high-energy molecules (NADH and FADH₂) that
will be later used to generate ATP in the electron transport chain
Rationale: The citric acid cycle generates high-energy molecules (NADH and
FADH₂) that will be later used to generate ATP in the electron transport chain.
It does not directly produce the majority of ATP.
4. The electron transport chain directly produces ATP.
A) True
B) False
Correct Answer: False
Rationale: The ETC does not directly produce any ATP. However, establishing
a proton gradient across the mitochondrial membrane will lead to the
production of ATP via ATP synthase. ATP is produced through chemiosmosis,
not directly by the ETC.
5. What is the role of ATP synthase in the electron transport chain?
A) To pump protons across the membrane
B) To generate ATP through chemiosmosis
C) To transfer electrons to oxygen
D) To break down glucose
, Correct Answer: To generate ATP through chemiosmosis
Rationale: ATP synthase is responsible for generating ATP through
chemiosmosis. Chemiosmosis is an energy-coupling process which harnesses
the energy that exists within the proton ion gradient and uses it to drive ATP
synthesis.
6. _______ respiration involves the consumption of oxygen, while _______
respiration can proceed in the absence of oxygen.
A) Aerobic; anaerobic
B) Anaerobic; aerobic
C) Cellular; fermentation
D) Oxidative; substrate-level
Correct Answer: Aerobic; anaerobic
Rationale: Aerobic respiration involves the consumption of oxygen, while
anaerobic respiration can proceed in the absence of oxygen. This is a
fundamental distinction in cellular respiration.
7. The first step of the citric acid cycle is a preparation phase sometimes
called:
A) Glycolysis
B) Pyruvate oxidation
C) Fermentation
D) Oxidative phosphorylation
Correct Answer: Pyruvate oxidation
