C785 Biochemistry Module 1 Comprehensive Review 2026 |WGU
1. Which property of water allows it to act as a versatile solvent in biological
systems?
A. Its ability to form covalent bonds with solutes
B. Its non-polar nature
C. Its polarity and ability to form hydrogen bonds
D. Its high density in solid form
Answer: C
Rationale: Water’s polarity allows it to surround and interact with both ionic and polar
substances, making it an excellent solvent.
2. What is the relationship between pH and hydrogen ion concentration [H+]?
A. pH is directly proportional to [H+]
B. pH is the negative logarithm of [H+]
C. pH remains constant regardless of [H+]
D. pH is the square root of [H+]
Answer: B
Rationale: The pH scale is logarithmic; as the concentration of hydrogen ions increases,
the pH value decreases.
3. Which part of an amino acid defines its unique chemical properties?
A. The amino group
B. The carboxyl group
C. The side chain (R-group)
D. The central alpha carbon
Answer: C
,Rationale: While all amino acids share a common backbone, the R-group varies and
determines the chemical behavior of the amino acid.
4. A peptide bond is formed through which type of reaction?
A. Hydrolysis
B. Oxidation-reduction
C. Dehydration synthesis
D. Hydrogenation
Answer: C
Rationale: A peptide bond forms when the carboxyl group of one amino acid reacts with
the amino group of another, releasing a water molecule.
5. The linear sequence of amino acids in a polypeptide chain represents which
level of protein structure?
A. Quaternary
B. Secondary
C. Tertiary
D. Primary
Answer: D
Rationale: The primary structure is the specific order of amino acids held together by
peptide bonds.
6. What type of bonding primarily stabilizes alpha-helices and beta-pleated
sheets?
A. Ionic bonds
B. Disulfide bridges
C. Hydrogen bonds
D. Hydrophobic interactions
Answer: C
, Rationale: Secondary structures are stabilized by hydrogen bonds between the backbone
amino and carboxyl groups.
7. Which level of protein structure describes the overall three-dimensional
folding of a single polypeptide?
A. Primary
B. Tertiary
C. Secondary
D. Quaternary
Answer: B
Rationale: Tertiary structure refers to the 3D shape formed by interactions between R-
groups.
8. A protein composed of multiple polypeptide chains exhibits which level of
structure?
A. Secondary
B. Tertiary
C. Quaternary
D. Super-secondary
Answer: C
Rationale: Quaternary structure refers to the arrangement and interaction of multiple
protein subunits.
9. Which of the following describes a function of hemoglobin?
A. Oxygen storage in muscle cells
B. Oxygen transport in the blood
C. Catalyzing the breakdown of glucose
D. Structural support in connective tissue
Answer: B
1. Which property of water allows it to act as a versatile solvent in biological
systems?
A. Its ability to form covalent bonds with solutes
B. Its non-polar nature
C. Its polarity and ability to form hydrogen bonds
D. Its high density in solid form
Answer: C
Rationale: Water’s polarity allows it to surround and interact with both ionic and polar
substances, making it an excellent solvent.
2. What is the relationship between pH and hydrogen ion concentration [H+]?
A. pH is directly proportional to [H+]
B. pH is the negative logarithm of [H+]
C. pH remains constant regardless of [H+]
D. pH is the square root of [H+]
Answer: B
Rationale: The pH scale is logarithmic; as the concentration of hydrogen ions increases,
the pH value decreases.
3. Which part of an amino acid defines its unique chemical properties?
A. The amino group
B. The carboxyl group
C. The side chain (R-group)
D. The central alpha carbon
Answer: C
,Rationale: While all amino acids share a common backbone, the R-group varies and
determines the chemical behavior of the amino acid.
4. A peptide bond is formed through which type of reaction?
A. Hydrolysis
B. Oxidation-reduction
C. Dehydration synthesis
D. Hydrogenation
Answer: C
Rationale: A peptide bond forms when the carboxyl group of one amino acid reacts with
the amino group of another, releasing a water molecule.
5. The linear sequence of amino acids in a polypeptide chain represents which
level of protein structure?
A. Quaternary
B. Secondary
C. Tertiary
D. Primary
Answer: D
Rationale: The primary structure is the specific order of amino acids held together by
peptide bonds.
6. What type of bonding primarily stabilizes alpha-helices and beta-pleated
sheets?
A. Ionic bonds
B. Disulfide bridges
C. Hydrogen bonds
D. Hydrophobic interactions
Answer: C
, Rationale: Secondary structures are stabilized by hydrogen bonds between the backbone
amino and carboxyl groups.
7. Which level of protein structure describes the overall three-dimensional
folding of a single polypeptide?
A. Primary
B. Tertiary
C. Secondary
D. Quaternary
Answer: B
Rationale: Tertiary structure refers to the 3D shape formed by interactions between R-
groups.
8. A protein composed of multiple polypeptide chains exhibits which level of
structure?
A. Secondary
B. Tertiary
C. Quaternary
D. Super-secondary
Answer: C
Rationale: Quaternary structure refers to the arrangement and interaction of multiple
protein subunits.
9. Which of the following describes a function of hemoglobin?
A. Oxygen storage in muscle cells
B. Oxygen transport in the blood
C. Catalyzing the breakdown of glucose
D. Structural support in connective tissue
Answer: B
