WGU C785 Biochemistry Questions
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A Instant
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1. Which level of protein structure is determined directly by the amino acid
sequence?
A. Secondary
B. Tertiary
C. Quaternary
D. Primary
Correct Answer: Primary
Rationale: The primary structure is the linear sequence of amino acids connected
by peptide bonds. All higher levels of structure depend on this sequence.
2. Which bond primarily stabilizes the alpha-helix structure of proteins?
A. Peptide bonds
B. Hydrogen bonds
C. Ionic bonds
D. Disulfide bonds
Correct Answer: Hydrogen bonds
,Rationale: Hydrogen bonds form between backbone carbonyl oxygens and amide
hydrogens, stabilizing the alpha-helix.
3. Which amino acid contains sulfur and can form disulfide bonds?
A. Glycine
B. Alanine
C. Cysteine
D. Valine
Correct Answer: Cysteine
Rationale: Two cysteine residues can oxidize to form a disulfide bridge, increasing
protein stability.
4. An enzyme lowers activation energy by:
A. Increasing product energy
B. Stabilizing the transition state
C. Raising substrate energy
D. Changing ΔG
Correct Answer: Stabilizing the transition state
Rationale: Enzymes accelerate reactions by lowering activation energy without
changing the overall free energy change (ΔG).
5. Which enzyme inhibition can be overcome by increasing substrate
concentration?
A. Noncompetitive
B. Competitive
,C. Irreversible
D. Uncompetitive
Correct Answer: Competitive
Rationale: Competitive inhibitors bind the active site, so increasing substrate
concentration reduces inhibition.
6. Michaelis-Menten kinetics describes the relationship between:
A. Temperature and enzyme activity
B. Enzyme concentration and pH
C. Substrate concentration and reaction velocity
D. ATP concentration and metabolism
Correct Answer: Substrate concentration and reaction velocity
Rationale: The Michaelis-Menten equation relates substrate concentration to
enzyme reaction rate.
7. Which molecule serves as the primary energy currency of the cell?
A. NADH
B. ATP
C. GTP
D. FADH₂
Correct Answer: ATP
Rationale: ATP stores and transfers energy used in cellular work.
8. Glycolysis occurs in the:
, A. Mitochondrial matrix
B. Cytoplasm
C. Nucleus
D. Golgi apparatus
Correct Answer: Cytoplasm
Rationale: Glycolysis is the cytosolic pathway that converts glucose into pyruvate.
9. Glycolysis produces a net gain of:
A. 1 ATP
B. 2 ATP
C. 4 ATP
D. 8 ATP
Correct Answer: 2 ATP
Rationale: Glycolysis consumes 2 ATP and produces 4 ATP, yielding a net gain of 2
ATP.
10. Which process generates the greatest amount of ATP during aerobic
respiration?
A. Glycolysis
B. Citric acid cycle
C. Oxidative phosphorylation
D. Fermentation
Correct Answer: Oxidative phosphorylation
Rationale: Most ATP is produced by the electron transport chain and ATP
synthase.
And Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A Instant
Download Pdf
1. Which level of protein structure is determined directly by the amino acid
sequence?
A. Secondary
B. Tertiary
C. Quaternary
D. Primary
Correct Answer: Primary
Rationale: The primary structure is the linear sequence of amino acids connected
by peptide bonds. All higher levels of structure depend on this sequence.
2. Which bond primarily stabilizes the alpha-helix structure of proteins?
A. Peptide bonds
B. Hydrogen bonds
C. Ionic bonds
D. Disulfide bonds
Correct Answer: Hydrogen bonds
,Rationale: Hydrogen bonds form between backbone carbonyl oxygens and amide
hydrogens, stabilizing the alpha-helix.
3. Which amino acid contains sulfur and can form disulfide bonds?
A. Glycine
B. Alanine
C. Cysteine
D. Valine
Correct Answer: Cysteine
Rationale: Two cysteine residues can oxidize to form a disulfide bridge, increasing
protein stability.
4. An enzyme lowers activation energy by:
A. Increasing product energy
B. Stabilizing the transition state
C. Raising substrate energy
D. Changing ΔG
Correct Answer: Stabilizing the transition state
Rationale: Enzymes accelerate reactions by lowering activation energy without
changing the overall free energy change (ΔG).
5. Which enzyme inhibition can be overcome by increasing substrate
concentration?
A. Noncompetitive
B. Competitive
,C. Irreversible
D. Uncompetitive
Correct Answer: Competitive
Rationale: Competitive inhibitors bind the active site, so increasing substrate
concentration reduces inhibition.
6. Michaelis-Menten kinetics describes the relationship between:
A. Temperature and enzyme activity
B. Enzyme concentration and pH
C. Substrate concentration and reaction velocity
D. ATP concentration and metabolism
Correct Answer: Substrate concentration and reaction velocity
Rationale: The Michaelis-Menten equation relates substrate concentration to
enzyme reaction rate.
7. Which molecule serves as the primary energy currency of the cell?
A. NADH
B. ATP
C. GTP
D. FADH₂
Correct Answer: ATP
Rationale: ATP stores and transfers energy used in cellular work.
8. Glycolysis occurs in the:
, A. Mitochondrial matrix
B. Cytoplasm
C. Nucleus
D. Golgi apparatus
Correct Answer: Cytoplasm
Rationale: Glycolysis is the cytosolic pathway that converts glucose into pyruvate.
9. Glycolysis produces a net gain of:
A. 1 ATP
B. 2 ATP
C. 4 ATP
D. 8 ATP
Correct Answer: 2 ATP
Rationale: Glycolysis consumes 2 ATP and produces 4 ATP, yielding a net gain of 2
ATP.
10. Which process generates the greatest amount of ATP during aerobic
respiration?
A. Glycolysis
B. Citric acid cycle
C. Oxidative phosphorylation
D. Fermentation
Correct Answer: Oxidative phosphorylation
Rationale: Most ATP is produced by the electron transport chain and ATP
synthase.
