,BIOL 271 Module 2 Exam | Microbiology w/ Lab |
Portage Learning | Q & A | 2026/2027 Edition (PDF)
**1. Which term describes the sum of all chemical reactions that occur within a living organism?**
A) Anabolism
B) Catabolism
C) Metabolism
D) Homeostasis
Correct Answer: Metabolism
Rationale: Metabolism is the total of all biochemical reactions in an organism, encompassing both
catabolic (breakdown) and anabolic (synthesis) pathways. Anabolism specifically refers to biosynthetic
reactions, catabolism to degradative reactions, and homeostasis to maintaining internal stability.
Metabolism is the overarching term for all cellular chemical processes.
**2. The breakdown of large molecules into smaller ones, releasing energy, is termed:**
A) Catabolism
B) Anabolism
C) Endergonic synthesis
D) Feedback inhibition
Correct Answer: Catabolism
Rationale: Catabolism is the degradative phase of metabolism that breaks down complex molecules into
simpler ones, releasing energy in the process. Anabolism is the synthetic phase that builds complex
molecules and requires energy. Endergonic synthesis is a type of anabolism, and feedback inhibition is a
regulatory mechanism.
**3. During the growth and repair phase after a cell injury, which metabolic process is primarily active?
**
,A) Catabolism
B) Anabolism
C) Fermentation
D) Glycolysis
Correct Answer: Anabolism
Rationale: Anabolism is the biosynthetic process that builds complex macromolecules from simpler
precursors, requiring energy input. During growth and repair, cells actively synthesize proteins, nucleic
acids, and other cellular components. Catabolism breaks down molecules, while fermentation and
glycolysis are primarily energy-yielding processes.
**4. Enzymes function by which of the following mechanisms?**
A) Increasing the activation energy of a reaction
B) Decreasing the activation energy of a reaction
C) Being consumed during the reaction
D) Changing the equilibrium constant of a reaction
Correct Answer: Decreasing the activation energy of a reaction
Rationale: Enzymes are biological catalysts that speed up chemical reactions by lowering the activation
energy required for the reaction to proceed. They are not consumed during the reaction and can be
reused. Enzymes do not change the equilibrium constant; they only increase the rate at which
equilibrium is reached.
**5. Enzymes are primarily composed of which type of macromolecule?**
A) Polysaccharides
B) Lipids
C) Proteins
D) Nucleic acids
, Correct Answer: Proteins
Rationale: Enzymes are almost always proteins, though some RNA molecules (ribozymes) also have
catalytic activity. They are not polysaccharides, lipids, or nucleic acids in their primary structure. The
protein nature of enzymes allows for the specific three-dimensional structures that enable their catalytic
function.
**6. True or False: Enzymes are consumed during the chemical reactions they catalyze.**
A) True
B) False
Correct Answer: False
Rationale: Enzymes are not consumed during the chemical reactions they catalyze; they can be reused
multiple times. Enzymes lower the activation energy and facilitate the reaction without being
permanently altered or consumed. This catalytic property allows small amounts of enzyme to process
large amounts of substrate.
**7. The specific molecule upon which an enzyme acts is called the:**
A) Cofactor
B) Substrate
C) Product
D) Coenzyme
Correct Answer: Substrate
Rationale: The substrate is the specific molecule that an enzyme acts upon, binding to the enzyme's
active site. Cofactors and coenzymes are non-protein molecules that assist enzymes in catalysis.
Products are the molecules formed after the reaction. The substrate-enzyme interaction is highly
specific.
**8. Which of the following best describes the induced fit model of enzyme action?**
Portage Learning | Q & A | 2026/2027 Edition (PDF)
**1. Which term describes the sum of all chemical reactions that occur within a living organism?**
A) Anabolism
B) Catabolism
C) Metabolism
D) Homeostasis
Correct Answer: Metabolism
Rationale: Metabolism is the total of all biochemical reactions in an organism, encompassing both
catabolic (breakdown) and anabolic (synthesis) pathways. Anabolism specifically refers to biosynthetic
reactions, catabolism to degradative reactions, and homeostasis to maintaining internal stability.
Metabolism is the overarching term for all cellular chemical processes.
**2. The breakdown of large molecules into smaller ones, releasing energy, is termed:**
A) Catabolism
B) Anabolism
C) Endergonic synthesis
D) Feedback inhibition
Correct Answer: Catabolism
Rationale: Catabolism is the degradative phase of metabolism that breaks down complex molecules into
simpler ones, releasing energy in the process. Anabolism is the synthetic phase that builds complex
molecules and requires energy. Endergonic synthesis is a type of anabolism, and feedback inhibition is a
regulatory mechanism.
**3. During the growth and repair phase after a cell injury, which metabolic process is primarily active?
**
,A) Catabolism
B) Anabolism
C) Fermentation
D) Glycolysis
Correct Answer: Anabolism
Rationale: Anabolism is the biosynthetic process that builds complex macromolecules from simpler
precursors, requiring energy input. During growth and repair, cells actively synthesize proteins, nucleic
acids, and other cellular components. Catabolism breaks down molecules, while fermentation and
glycolysis are primarily energy-yielding processes.
**4. Enzymes function by which of the following mechanisms?**
A) Increasing the activation energy of a reaction
B) Decreasing the activation energy of a reaction
C) Being consumed during the reaction
D) Changing the equilibrium constant of a reaction
Correct Answer: Decreasing the activation energy of a reaction
Rationale: Enzymes are biological catalysts that speed up chemical reactions by lowering the activation
energy required for the reaction to proceed. They are not consumed during the reaction and can be
reused. Enzymes do not change the equilibrium constant; they only increase the rate at which
equilibrium is reached.
**5. Enzymes are primarily composed of which type of macromolecule?**
A) Polysaccharides
B) Lipids
C) Proteins
D) Nucleic acids
, Correct Answer: Proteins
Rationale: Enzymes are almost always proteins, though some RNA molecules (ribozymes) also have
catalytic activity. They are not polysaccharides, lipids, or nucleic acids in their primary structure. The
protein nature of enzymes allows for the specific three-dimensional structures that enable their catalytic
function.
**6. True or False: Enzymes are consumed during the chemical reactions they catalyze.**
A) True
B) False
Correct Answer: False
Rationale: Enzymes are not consumed during the chemical reactions they catalyze; they can be reused
multiple times. Enzymes lower the activation energy and facilitate the reaction without being
permanently altered or consumed. This catalytic property allows small amounts of enzyme to process
large amounts of substrate.
**7. The specific molecule upon which an enzyme acts is called the:**
A) Cofactor
B) Substrate
C) Product
D) Coenzyme
Correct Answer: Substrate
Rationale: The substrate is the specific molecule that an enzyme acts upon, binding to the enzyme's
active site. Cofactors and coenzymes are non-protein molecules that assist enzymes in catalysis.
Products are the molecules formed after the reaction. The substrate-enzyme interaction is highly
specific.
**8. Which of the following best describes the induced fit model of enzyme action?**
