,CHEM 210 Exam 7 | Biochemistry Exam Q&A
| Portage Learning
1. Which of the following best defines the term metabolism?
A) The breakdown of large molecules into smaller ones
B) The sum of all chemical reactions occurring within a living organism
C) The synthesis of complex molecules from simpler ones
D) The transfer of electrons between molecules
Correct Answer: The sum of all chemical reactions occurring within a living organism
Rationale: Metabolism encompasses all chemical reactions in a cell, including both
catabolic (breakdown) and anabolic (synthesis) pathways. Catabolism and anabolism are
subsets of metabolism, while electron transfer is a specific type of reaction that occurs
within metabolic pathways.
2. A biochemical metabolic pathway is best described as:
A) A single reaction that converts starting material into products
B) A series of enzyme-catalyzed reactions that convert a starting material into a product
C) A random collection of unrelated chemical reactions
D) A process that only occurs in the absence of oxygen
Correct Answer: A series of enzyme-catalyzed reactions that convert a starting
material into a product
,Rationale: Metabolic pathways are organized sequences of enzyme-catalyzed
reactions, each step transforming a metabolite into the next. They are not single
reactions, random collections, or exclusively anaerobic processes. This organization
allows for efficient regulation and energy capture.
3. Which of the following best describes catabolism?
A) The synthesis of complex molecules from simpler ones
B) The breakdown of complex molecules into simpler ones, releasing energy
C) The storage of energy in the form of glycogen
D) The transport of molecules across cell membranes
Correct Answer: The breakdown of complex molecules into simpler ones, releasing
energy
Rationale: Catabolism is the degradative phase of metabolism in which complex
molecules such as carbohydrates and fats are broken down into simpler ones like CO₂
and water, releasing energy. Anabolism is the synthetic phase that consumes energy.
4. Which of the following best describes anabolism?
A) The breakdown of glucose to pyruvate
B) The synthesis of complex molecules from simpler ones, requiring energy
C) The oxidation of fatty acids to acetyl-CoA
D) The transfer of electrons to oxygen
, Correct Answer: The synthesis of complex molecules from simpler ones, requiring
energy
Rationale: Anabolism is the biosynthetic phase of metabolism that builds complex
molecules such as proteins, nucleic acids, and polysaccharides from simpler precursors.
It requires energy, often provided by ATP. Catabolism is the energy-releasing breakdown
phase.
5. In a biochemical reaction, the change in free energy (ΔG) is negative. This indicates
that the reaction is:
A) Endergonic and non-spontaneous
B) Exergonic and spontaneous
C) At equilibrium
D) Coupled to ATP hydrolysis
Correct Answer: Exergonic and spontaneous
Rationale: A negative ΔG indicates that the reaction releases free energy and is
spontaneous (exergonic). A positive ΔG indicates an endergonic, non-spontaneous
reaction. Equilibrium is reached when ΔG equals zero.
6. A reaction has a ΔG of +52 kJ/mol. This value indicates that the reaction is:
A) Spontaneous and exergonic
B) Non-spontaneous and endergonic
C) At equilibrium
D) Coupled to ATP synthesis
| Portage Learning
1. Which of the following best defines the term metabolism?
A) The breakdown of large molecules into smaller ones
B) The sum of all chemical reactions occurring within a living organism
C) The synthesis of complex molecules from simpler ones
D) The transfer of electrons between molecules
Correct Answer: The sum of all chemical reactions occurring within a living organism
Rationale: Metabolism encompasses all chemical reactions in a cell, including both
catabolic (breakdown) and anabolic (synthesis) pathways. Catabolism and anabolism are
subsets of metabolism, while electron transfer is a specific type of reaction that occurs
within metabolic pathways.
2. A biochemical metabolic pathway is best described as:
A) A single reaction that converts starting material into products
B) A series of enzyme-catalyzed reactions that convert a starting material into a product
C) A random collection of unrelated chemical reactions
D) A process that only occurs in the absence of oxygen
Correct Answer: A series of enzyme-catalyzed reactions that convert a starting
material into a product
,Rationale: Metabolic pathways are organized sequences of enzyme-catalyzed
reactions, each step transforming a metabolite into the next. They are not single
reactions, random collections, or exclusively anaerobic processes. This organization
allows for efficient regulation and energy capture.
3. Which of the following best describes catabolism?
A) The synthesis of complex molecules from simpler ones
B) The breakdown of complex molecules into simpler ones, releasing energy
C) The storage of energy in the form of glycogen
D) The transport of molecules across cell membranes
Correct Answer: The breakdown of complex molecules into simpler ones, releasing
energy
Rationale: Catabolism is the degradative phase of metabolism in which complex
molecules such as carbohydrates and fats are broken down into simpler ones like CO₂
and water, releasing energy. Anabolism is the synthetic phase that consumes energy.
4. Which of the following best describes anabolism?
A) The breakdown of glucose to pyruvate
B) The synthesis of complex molecules from simpler ones, requiring energy
C) The oxidation of fatty acids to acetyl-CoA
D) The transfer of electrons to oxygen
, Correct Answer: The synthesis of complex molecules from simpler ones, requiring
energy
Rationale: Anabolism is the biosynthetic phase of metabolism that builds complex
molecules such as proteins, nucleic acids, and polysaccharides from simpler precursors.
It requires energy, often provided by ATP. Catabolism is the energy-releasing breakdown
phase.
5. In a biochemical reaction, the change in free energy (ΔG) is negative. This indicates
that the reaction is:
A) Endergonic and non-spontaneous
B) Exergonic and spontaneous
C) At equilibrium
D) Coupled to ATP hydrolysis
Correct Answer: Exergonic and spontaneous
Rationale: A negative ΔG indicates that the reaction releases free energy and is
spontaneous (exergonic). A positive ΔG indicates an endergonic, non-spontaneous
reaction. Equilibrium is reached when ΔG equals zero.
6. A reaction has a ΔG of +52 kJ/mol. This value indicates that the reaction is:
A) Spontaneous and exergonic
B) Non-spontaneous and endergonic
C) At equilibrium
D) Coupled to ATP synthesis
