C785 Biochemistry Week 1 Study Guide Comprehensive Quiz 2026
|WGU
1. Which of the following properties of water allows it to act as an efficient
solvent for biological molecules?
A. High surface tension
B. High specific heat
C. Polarity and hydrogen bonding capacity
D. Low density as a solid
Answer: C
Rationale: Water’s polarity and ability to form hydrogen bonds allow it to interact with
and dissolve other polar and ionic substances.
2. A buffer solution is most effective when:
A. The pH is much higher than the pKa
B. The pH is much lower than the pKa
C. The pH is equal to the pKa
D. The concentration of conjugate base is zero
Answer: C
Rationale: The buffering capacity is maximal when the pH equals the pKa, as there are
equal amounts of acid and conjugate base to resist pH changes.
,3. What is the primary driving force for the folding of proteins in an aqueous
environment?
A. Covalent bonding
B. The hydrophobic effect
C. Ionic interactions
D. Metallic bonding
Answer: B
Rationale: The hydrophobic effect drives nonpolar side chains away from water into the
protein interior, which is the main factor in protein folding.
4. Which part of an amino acid is unique and determines its chemical
properties?
A. The side chain (R-group)
B. The carboxyl group
C. The alpha carbon
D. The amino group
Answer: A
Rationale: While all amino acids share the amino, carboxyl, and alpha carbon structure, the
R-group is unique to each and determines its function.
5. Which of the following amino acids is classified as nonpolar?
A. Serine
B. Lysine
C. Aspartate
D. Leucine
Answer: D
Rationale: Leucine has an aliphatic hydrocarbon side chain, making it nonpolar and
hydrophobic.
, 6. Which amino acid is capable of forming disulfide bonds?
A. Methionine
B. Valine
C. Alanine
D. Cysteine
Answer: D
Rationale: Cysteine contains a thiol (-SH) group that can oxidize to form a covalent
disulfide bridge with another cysteine.
7. The peptide bond is formed through which type of reaction?
A. Hydrolysis
B. Oxidation
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.
8. Primary structure of a protein refers to:
A. The sequence of amino acids
B. The alpha helix and beta sheets
C. The overall 3D shape
D. The interaction between multiple subunits
Answer: A
Rationale: The primary structure is the linear sequence of amino acids held together by
peptide bonds.
|WGU
1. Which of the following properties of water allows it to act as an efficient
solvent for biological molecules?
A. High surface tension
B. High specific heat
C. Polarity and hydrogen bonding capacity
D. Low density as a solid
Answer: C
Rationale: Water’s polarity and ability to form hydrogen bonds allow it to interact with
and dissolve other polar and ionic substances.
2. A buffer solution is most effective when:
A. The pH is much higher than the pKa
B. The pH is much lower than the pKa
C. The pH is equal to the pKa
D. The concentration of conjugate base is zero
Answer: C
Rationale: The buffering capacity is maximal when the pH equals the pKa, as there are
equal amounts of acid and conjugate base to resist pH changes.
,3. What is the primary driving force for the folding of proteins in an aqueous
environment?
A. Covalent bonding
B. The hydrophobic effect
C. Ionic interactions
D. Metallic bonding
Answer: B
Rationale: The hydrophobic effect drives nonpolar side chains away from water into the
protein interior, which is the main factor in protein folding.
4. Which part of an amino acid is unique and determines its chemical
properties?
A. The side chain (R-group)
B. The carboxyl group
C. The alpha carbon
D. The amino group
Answer: A
Rationale: While all amino acids share the amino, carboxyl, and alpha carbon structure, the
R-group is unique to each and determines its function.
5. Which of the following amino acids is classified as nonpolar?
A. Serine
B. Lysine
C. Aspartate
D. Leucine
Answer: D
Rationale: Leucine has an aliphatic hydrocarbon side chain, making it nonpolar and
hydrophobic.
, 6. Which amino acid is capable of forming disulfide bonds?
A. Methionine
B. Valine
C. Alanine
D. Cysteine
Answer: D
Rationale: Cysteine contains a thiol (-SH) group that can oxidize to form a covalent
disulfide bridge with another cysteine.
7. The peptide bond is formed through which type of reaction?
A. Hydrolysis
B. Oxidation
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.
8. Primary structure of a protein refers to:
A. The sequence of amino acids
B. The alpha helix and beta sheets
C. The overall 3D shape
D. The interaction between multiple subunits
Answer: A
Rationale: The primary structure is the linear sequence of amino acids held together by
peptide bonds.
