BIOCHEM 210 COMPREHENSIVE EXAM
(MODULES 1-8) QUESTIONS WITH
VERIFIED ANSWERS
1. Which property of water allows it to act as an efficient biological solvent?
A. Its linear geometry
B. Its non-polar nature
C. Its lack of hydrogen bonding
D. Its high dielectric constant
Answer: D
Conceptual Explanation: Water’s high dielectric constant allows it to screen electrostatic
interactions between ions, making it an excellent solvent for polar and ionic substances.
2. What is the primary driving force for the folding of globular proteins?
A. Ionic bonding
B. Hydrogen bonding between side chains
C. Disulfide bridges
D. The hydrophobic effect
,Answer: D
Conceptual Explanation: The hydrophobic effect minimizes the surface area of non-polar
groups exposed to water, significantly increasing entropy and driving the protein into its
folded state.
3. Which amino acid is considered ‘achiral’ because its R group is a hydrogen atom?
A. Alanine
B. Proline
C. Glycine
D. Valine
Answer: C
Conceptual Explanation: Glycine’s side chain is a hydrogen atom, making the alpha-
carbon bonded to two identical groups, thus it is not a chiral center.
4. In a titration curve of a weak acid, the pH is equal to the pKa when:
A. [Acid] = [Conjugate Base]
B. The acid is fully deprotonated
C. The solution is neutral (pH 7.0)
D. The acid is fully protonated
Answer: A
, Conceptual Explanation: According to the Henderson-Hasselbalch equation, when [A-] =
[HA], the log(1) term is zero, and pH equals pKa.
5. Which type of secondary structure is characterized by R groups pointing outward from a
central helical axis?
A. Beta-pleated sheet
B. Alpha-helix
C. Beta-turn
D. Random coil
Answer: B
Conceptual Explanation: In an alpha-helix, the polypeptide backbone forms the inner part
of the rod and the side chains extend outward.
6. A Ramachandran plot shows the sterically allowed rotations of which two bonds?
A. C-N (peptide bond) and C-O
B. C-alpha and the R group
C. Phi and Psi bonds
D. Hydrogen bonds and ionic bonds
Answer: C
Conceptual Explanation: The Ramachandran plot maps the torsion angles phi (around N-
C_alpha) and psi (around C_alpha-C) to predict stable secondary structures.
(MODULES 1-8) QUESTIONS WITH
VERIFIED ANSWERS
1. Which property of water allows it to act as an efficient biological solvent?
A. Its linear geometry
B. Its non-polar nature
C. Its lack of hydrogen bonding
D. Its high dielectric constant
Answer: D
Conceptual Explanation: Water’s high dielectric constant allows it to screen electrostatic
interactions between ions, making it an excellent solvent for polar and ionic substances.
2. What is the primary driving force for the folding of globular proteins?
A. Ionic bonding
B. Hydrogen bonding between side chains
C. Disulfide bridges
D. The hydrophobic effect
,Answer: D
Conceptual Explanation: The hydrophobic effect minimizes the surface area of non-polar
groups exposed to water, significantly increasing entropy and driving the protein into its
folded state.
3. Which amino acid is considered ‘achiral’ because its R group is a hydrogen atom?
A. Alanine
B. Proline
C. Glycine
D. Valine
Answer: C
Conceptual Explanation: Glycine’s side chain is a hydrogen atom, making the alpha-
carbon bonded to two identical groups, thus it is not a chiral center.
4. In a titration curve of a weak acid, the pH is equal to the pKa when:
A. [Acid] = [Conjugate Base]
B. The acid is fully deprotonated
C. The solution is neutral (pH 7.0)
D. The acid is fully protonated
Answer: A
, Conceptual Explanation: According to the Henderson-Hasselbalch equation, when [A-] =
[HA], the log(1) term is zero, and pH equals pKa.
5. Which type of secondary structure is characterized by R groups pointing outward from a
central helical axis?
A. Beta-pleated sheet
B. Alpha-helix
C. Beta-turn
D. Random coil
Answer: B
Conceptual Explanation: In an alpha-helix, the polypeptide backbone forms the inner part
of the rod and the side chains extend outward.
6. A Ramachandran plot shows the sterically allowed rotations of which two bonds?
A. C-N (peptide bond) and C-O
B. C-alpha and the R group
C. Phi and Psi bonds
D. Hydrogen bonds and ionic bonds
Answer: C
Conceptual Explanation: The Ramachandran plot maps the torsion angles phi (around N-
C_alpha) and psi (around C_alpha-C) to predict stable secondary structures.
