,CHEM 210 Exam 8 | Biochemistry Exam Q&A
| Portage Learning
1. Which of the following best describes the relationship between catabolic and anabolic
pathways in cellular metabolism?
A) Catabolic pathways consume energy to build complex molecules, while anabolic
pathways release energy by breaking down molecules
B) Catabolic pathways break down complex molecules into simpler ones and release
energy, while anabolic pathways synthesize complex molecules from simpler ones and
consume energy
C) Both catabolic and anabolic pathways consume energy to build complex molecules
D) Both catabolic and anabolic pathways release energy by breaking down complex
molecules
Correct Answer: Catabolic pathways break down complex molecules into simpler
ones and release energy, while anabolic pathways synthesize complex molecules from
simpler ones and consume energy
Rationale: Catabolism is the exergonic phase of metabolism that degrades complex
molecules such as glucose and fatty acids into simpler products like CO₂ and water,
releasing energy that is captured as ATP and reducing equivalents. Anabolism is the
endergonic phase that uses this energy to synthesize complex biomolecules from
simpler precursors. The two pathways are reciprocally regulated to prevent futile cycling.
2. What is the primary role of ATP in metabolic integration?
A) It serves as a long-term energy storage molecule
,B) It acts as the universal energy currency that couples exergonic and endergonic
reactions
C) It serves as a structural component of cell membranes
D) It functions as a genetic information carrier
Correct Answer: It acts as the universal energy currency that couples exergonic and
endergonic reactions
Rationale: ATP is the primary energy currency of the cell, linking catabolic reactions
that produce ATP to anabolic reactions that consume ATP. Its hydrolysis releases free
energy that drives thermodynamically unfavorable processes. ATP is not a long-term
energy store, a membrane component, or a genetic material.
3. Which molecule serves as the central metabolic hub connecting carbohydrate, lipid,
and amino acid metabolism?
A) Glucose
B) Pyruvate
C) Acetyl-CoA
D) Lactate
Correct Answer: Acetyl-CoA
Rationale: Acetyl-CoA is the central metabolic intermediate where carbohydrate, lipid,
and amino acid catabolism converge. It enters the citric acid cycle for complete
oxidation and serves as the starting material for fatty acid synthesis and ketogenesis.
Pyruvate and lactate are glycolytic intermediates, and glucose is a carbohydrate
substrate.
, 4. Which of the following best describes the role of NADPH in metabolism?
A) It is the primary electron carrier in oxidative phosphorylation
B) It provides reducing power for anabolic reactions such as fatty acid synthesis
C) It serves as the terminal electron acceptor in the electron transport chain
D) It activates glycolytic enzymes
Correct Answer: It provides reducing power for anabolic reactions such as fatty acid
synthesis
Rationale: NADPH serves as the primary reducing agent in anabolic reactions,
including fatty acid synthesis, cholesterol synthesis, and nucleotide biosynthesis. NADH
is the primary electron carrier in oxidative phosphorylation, and oxygen is the terminal
electron acceptor.
5. Which of the following is the primary site of metabolic integration in the body?
A) Muscle
B) Adipose tissue
C) Liver
D) Brain
Correct Answer: Liver
Rationale: The liver is the central metabolic organ that integrates carbohydrate, lipid,
and amino acid metabolism. It maintains blood glucose homeostasis, synthesizes
| Portage Learning
1. Which of the following best describes the relationship between catabolic and anabolic
pathways in cellular metabolism?
A) Catabolic pathways consume energy to build complex molecules, while anabolic
pathways release energy by breaking down molecules
B) Catabolic pathways break down complex molecules into simpler ones and release
energy, while anabolic pathways synthesize complex molecules from simpler ones and
consume energy
C) Both catabolic and anabolic pathways consume energy to build complex molecules
D) Both catabolic and anabolic pathways release energy by breaking down complex
molecules
Correct Answer: Catabolic pathways break down complex molecules into simpler
ones and release energy, while anabolic pathways synthesize complex molecules from
simpler ones and consume energy
Rationale: Catabolism is the exergonic phase of metabolism that degrades complex
molecules such as glucose and fatty acids into simpler products like CO₂ and water,
releasing energy that is captured as ATP and reducing equivalents. Anabolism is the
endergonic phase that uses this energy to synthesize complex biomolecules from
simpler precursors. The two pathways are reciprocally regulated to prevent futile cycling.
2. What is the primary role of ATP in metabolic integration?
A) It serves as a long-term energy storage molecule
,B) It acts as the universal energy currency that couples exergonic and endergonic
reactions
C) It serves as a structural component of cell membranes
D) It functions as a genetic information carrier
Correct Answer: It acts as the universal energy currency that couples exergonic and
endergonic reactions
Rationale: ATP is the primary energy currency of the cell, linking catabolic reactions
that produce ATP to anabolic reactions that consume ATP. Its hydrolysis releases free
energy that drives thermodynamically unfavorable processes. ATP is not a long-term
energy store, a membrane component, or a genetic material.
3. Which molecule serves as the central metabolic hub connecting carbohydrate, lipid,
and amino acid metabolism?
A) Glucose
B) Pyruvate
C) Acetyl-CoA
D) Lactate
Correct Answer: Acetyl-CoA
Rationale: Acetyl-CoA is the central metabolic intermediate where carbohydrate, lipid,
and amino acid catabolism converge. It enters the citric acid cycle for complete
oxidation and serves as the starting material for fatty acid synthesis and ketogenesis.
Pyruvate and lactate are glycolytic intermediates, and glucose is a carbohydrate
substrate.
, 4. Which of the following best describes the role of NADPH in metabolism?
A) It is the primary electron carrier in oxidative phosphorylation
B) It provides reducing power for anabolic reactions such as fatty acid synthesis
C) It serves as the terminal electron acceptor in the electron transport chain
D) It activates glycolytic enzymes
Correct Answer: It provides reducing power for anabolic reactions such as fatty acid
synthesis
Rationale: NADPH serves as the primary reducing agent in anabolic reactions,
including fatty acid synthesis, cholesterol synthesis, and nucleotide biosynthesis. NADH
is the primary electron carrier in oxidative phosphorylation, and oxygen is the terminal
electron acceptor.
5. Which of the following is the primary site of metabolic integration in the body?
A) Muscle
B) Adipose tissue
C) Liver
D) Brain
Correct Answer: Liver
Rationale: The liver is the central metabolic organ that integrates carbohydrate, lipid,
and amino acid metabolism. It maintains blood glucose homeostasis, synthesizes
