Biochemistry C785 Final Exam Prep 2026 |WGU
1. Which level of protein structure is defined by the specific sequence of amino
acids linked by peptide bonds?
A. Secondary structure
B. Primary structure
C. Tertiary structure
D. Quaternary structure
Answer: B
Rationale: Primary structure refers specifically to the linear sequence of amino acids in a
polypeptide chain.
2. What effect does a competitive inhibitor have on the enzyme kinetics
parameters Km and Vmax?
A. Km increases, Vmax remains unchanged
B. Km decreases, Vmax remains unchanged
C. Km remains unchanged, Vmax decreases
D. Both Km and Vmax decrease
Answer: A
Rationale: Competitive inhibitors compete with the substrate for the active site, increasing
the apparent Km while Vmax stays the same.
,3. In the Bohr effect, what happens to hemoglobin’s affinity for oxygen as pH
decreases?
A. Affinity increases, shifting the curve to the left
B. Affinity remains constant but oxygen binding is faster
C. Affinity decreases, shifting the curve to the right
D. Hemoglobin denatures and cannot bind oxygen
Answer: C
Rationale: A lower pH (acidic) results in decreased affinity of hemoglobin for oxygen,
facilitating oxygen release to tissues.
4. Which molecule acts as the primary carrier of chemical energy in the cell?
A. DNA
B. NADH
C. ATP
D. Glucose
Answer: C
Rationale: ATP (Adenosine Triphosphate) is the universal energy currency of cells.
5. Which of the following amino acids is considered non-polar and hydrophobic?
A. Leucine
B. Glutamate
C. Lysine
D. Serine
Answer: A
Rationale: Leucine has an aliphatic side chain, making it non-polar and hydrophobic.
, 6. During DNA replication, which enzyme is responsible for unwinding the
double helix?
A. Helicase
B. Ligase
C. DNA Polymerase
D. Primase
Answer: A
Rationale: Helicase breaks the hydrogen bonds between bases to unwind the DNA double
helix.
7. Which process converts glucose into two molecules of pyruvate?
A. Glycolysis
B. Gluconeogenesis
C. Beta-oxidation
D. Citric Acid Cycle
Answer: A
Rationale: Glycolysis is the metabolic pathway that breaks down glucose into pyruvate.
8. In RNA, which nitrogenous base replaces thymine?
A. Adenine
B. Cytosine
C. Guanine
D. Uracil
Answer: D
Rationale: RNA contains uracil instead of thymine, which is found in DNA.
1. Which level of protein structure is defined by the specific sequence of amino
acids linked by peptide bonds?
A. Secondary structure
B. Primary structure
C. Tertiary structure
D. Quaternary structure
Answer: B
Rationale: Primary structure refers specifically to the linear sequence of amino acids in a
polypeptide chain.
2. What effect does a competitive inhibitor have on the enzyme kinetics
parameters Km and Vmax?
A. Km increases, Vmax remains unchanged
B. Km decreases, Vmax remains unchanged
C. Km remains unchanged, Vmax decreases
D. Both Km and Vmax decrease
Answer: A
Rationale: Competitive inhibitors compete with the substrate for the active site, increasing
the apparent Km while Vmax stays the same.
,3. In the Bohr effect, what happens to hemoglobin’s affinity for oxygen as pH
decreases?
A. Affinity increases, shifting the curve to the left
B. Affinity remains constant but oxygen binding is faster
C. Affinity decreases, shifting the curve to the right
D. Hemoglobin denatures and cannot bind oxygen
Answer: C
Rationale: A lower pH (acidic) results in decreased affinity of hemoglobin for oxygen,
facilitating oxygen release to tissues.
4. Which molecule acts as the primary carrier of chemical energy in the cell?
A. DNA
B. NADH
C. ATP
D. Glucose
Answer: C
Rationale: ATP (Adenosine Triphosphate) is the universal energy currency of cells.
5. Which of the following amino acids is considered non-polar and hydrophobic?
A. Leucine
B. Glutamate
C. Lysine
D. Serine
Answer: A
Rationale: Leucine has an aliphatic side chain, making it non-polar and hydrophobic.
, 6. During DNA replication, which enzyme is responsible for unwinding the
double helix?
A. Helicase
B. Ligase
C. DNA Polymerase
D. Primase
Answer: A
Rationale: Helicase breaks the hydrogen bonds between bases to unwind the DNA double
helix.
7. Which process converts glucose into two molecules of pyruvate?
A. Glycolysis
B. Gluconeogenesis
C. Beta-oxidation
D. Citric Acid Cycle
Answer: A
Rationale: Glycolysis is the metabolic pathway that breaks down glucose into pyruvate.
8. In RNA, which nitrogenous base replaces thymine?
A. Adenine
B. Cytosine
C. Guanine
D. Uracil
Answer: D
Rationale: RNA contains uracil instead of thymine, which is found in DNA.
