Biochemistry Module 2 Exam (Water, Amino Acids, and Proteins)
Questions and Answers 2026 Geneva College
1. Which of the following properties of water is primarily responsible for its high
boiling point compared to other molecules of similar size?
A. Covalent bonding
B. Van der Waals forces
C. Hydrogen bonding
D. Ionic interactions
Answer: C
Rationale: Water molecules form extensive hydrogen bonds with each other, requiring
significant energy to break during the phase transition from liquid to gas.
2. The Henderson-Hasselbalch equation relates pH, pKa, and which of the
following?
A. Concentration of water
B. Temperature and pressure
C. The ionic product of water
D. Ratio of conjugate base to weak acid
Answer: D
Rationale: The equation is pH = pKa + log([A-]/[HA]), where [A-] is the conjugate base and
[HA] is the weak acid.
,3. Which amino acid lacks a chiral center at the alpha carbon?
A. Alanine
B. Valine
C. Proline
D. Glycine
Answer: D
Rationale: Glycine’s R-group is a hydrogen atom, making the alpha carbon bonded to two
identical groups (H), thus it is achiral.
4. At a pH above its isoelectric point (pI), a protein will have what net charge?
A. Positive
B. Neutral
C. Zero
D. Negative
Answer: D
Rationale: When the pH is higher than the pI, the protein loses protons and becomes
negatively charged.
5. Which of the following amino acids is classified as basic?
A. Phenylalanine
B. Glutamate
C. Asparagine
D. Lysine
Answer: D
Rationale: Lysine, Arginine, and Histidine are the three common amino acids with basic
side chains.
, 6. What type of bond stabilizes the primary structure of a protein?
A. Hydrogen bonds
B. Peptide bonds
C. Disulfide bridges
D. Hydrophobic interactions
Answer: B
Rationale: Primary structure is the linear sequence of amino acids held together by
covalent peptide bonds.
7. The alpha-helix and beta-pleated sheet are examples of which level of protein
structure?
A. Primary
B. Quaternary
C. Tertiary
D. Secondary
Answer: D
Rationale: Secondary structure refers to local folded structures that form within a
polypeptide due to interactions between atoms of the backbone.
8. Which amino acid is known as a ‘helix breaker’ because its cyclic structure
limits rotation?
A. Leucine
B. Proline
C. Serine
D. Methionine
Answer: B
Rationale: Proline’s rigid ring structure prevents it from fitting into a standard alpha-helix,
often causing a kink.
Questions and Answers 2026 Geneva College
1. Which of the following properties of water is primarily responsible for its high
boiling point compared to other molecules of similar size?
A. Covalent bonding
B. Van der Waals forces
C. Hydrogen bonding
D. Ionic interactions
Answer: C
Rationale: Water molecules form extensive hydrogen bonds with each other, requiring
significant energy to break during the phase transition from liquid to gas.
2. The Henderson-Hasselbalch equation relates pH, pKa, and which of the
following?
A. Concentration of water
B. Temperature and pressure
C. The ionic product of water
D. Ratio of conjugate base to weak acid
Answer: D
Rationale: The equation is pH = pKa + log([A-]/[HA]), where [A-] is the conjugate base and
[HA] is the weak acid.
,3. Which amino acid lacks a chiral center at the alpha carbon?
A. Alanine
B. Valine
C. Proline
D. Glycine
Answer: D
Rationale: Glycine’s R-group is a hydrogen atom, making the alpha carbon bonded to two
identical groups (H), thus it is achiral.
4. At a pH above its isoelectric point (pI), a protein will have what net charge?
A. Positive
B. Neutral
C. Zero
D. Negative
Answer: D
Rationale: When the pH is higher than the pI, the protein loses protons and becomes
negatively charged.
5. Which of the following amino acids is classified as basic?
A. Phenylalanine
B. Glutamate
C. Asparagine
D. Lysine
Answer: D
Rationale: Lysine, Arginine, and Histidine are the three common amino acids with basic
side chains.
, 6. What type of bond stabilizes the primary structure of a protein?
A. Hydrogen bonds
B. Peptide bonds
C. Disulfide bridges
D. Hydrophobic interactions
Answer: B
Rationale: Primary structure is the linear sequence of amino acids held together by
covalent peptide bonds.
7. The alpha-helix and beta-pleated sheet are examples of which level of protein
structure?
A. Primary
B. Quaternary
C. Tertiary
D. Secondary
Answer: D
Rationale: Secondary structure refers to local folded structures that form within a
polypeptide due to interactions between atoms of the backbone.
8. Which amino acid is known as a ‘helix breaker’ because its cyclic structure
limits rotation?
A. Leucine
B. Proline
C. Serine
D. Methionine
Answer: B
Rationale: Proline’s rigid ring structure prevents it from fitting into a standard alpha-helix,
often causing a kink.
