WGU C785 Biochemistry Unit Exam Prep |
Complete Practice Questions with Verified
Answers & Rationales | Latest Update
2026/2027 Edition
Question 1
Which level of protein structure is disrupted through the hydrolysis of peptide bonds?
A. Quaternary
B. Tertiary
C. Primary
D. Secondary
Answer: C
Rationale: The primary structure of a protein is the sequence of amino acids held
together by peptide bonds. Peptide bonds are formed by dehydration reactions and
disrupted by hydrolysis.
Question 2
A mutation in the beta-hemoglobin gene, which results in the replacement of the amino
acid glutamate in position 6 with the amino acid valine, leads to the development of
sickle cell anemia. If the beta hemoglobin gene in a patient with sickle-cell anemia were
to be edited so that the valine in position 6 was replaced with a different amino acid,
which replacement for valine would be expected to have the best clinical outcome, in
theory, for the patient?
A. Isoleucine
B. Aspartate
C. Alanine
D. Leucine
Answer: B
Rationale: Glutamate is a charged, polar amino acid. Valine is nonpolar. Replacing
valine with another charged or polar amino acid like aspartate would most likely restore
normal protein folding and function. Isoleucine, alanine, and leucine are all nonpolar
amino acids and would not correct the hydrophobic interaction disruption.
pg. 1
,Question 3
An increase in beta-pleated sheet structure in some brain proteins can lead to an
increase in amyloid deposit formation, characteristic of some neurodegenerative
diseases. What is the primary biochemical process that follows the increase in beta-
pleated sheet structure that leads to the development of the amyloid deposits?
A. An increase in glycogen formation in the brain cells
B. Aggregation of the proteins in the brain
C. Secretion of glucagon, leading to excessive ketogenesis
D. An increase in anaerobic metabolism of glucose in the brain
Answer: B
Rationale: Aggregation occurs when proteins clump together inappropriately, causing
plaques like amyloid deposits to accumulate.
Question 4
Which level of protein structure is determined by the sequence of amino acids?
A. Secondary structure
B. Quaternary structure
C. Tertiary structure
D. Primary structure
Answer: D
Rationale: The primary structure of a protein is simply the sequence of amino acids
held together by peptide bonds.
Question 5
Which force is most influential in determining the secondary structure of a protein?
A. Hydrophobic effect
B. Disulfide bonding
C. Hydrogen bonding
D. Electrostatic interactions
Answer: C
Rationale: The secondary structure of a protein is built by hydrogen bonds between
the carboxyl groups and amino groups on the backbones of the amino acids.
Question 6
Which amino acid shown below would most likely participate in hydrogen bonds?
pg. 2
, A. Structure 1 (CH3-CH2-CH2-CH2-)
B. Structure 2 (HO-CH2-)
C. Structure 3 (CH3-CH2-S-)
D. Structure 4 (CH3-CH2-CH3)
Answer: B
Rationale: The OH group on the side chain makes this a polar, uncharged amino acid.
Polar, uncharged amino acids containing oxygen or NH groups readily form hydrogen
bonds.
Question 7
Which portion of the amino acid is indicated by the box in the diagram below?
A. Amino group
B. Carboxyl group
C. Side Chain (R group)
D. Alpha Carbon
Answer: C
Rationale: The side chain is the variable group of the amino acid, also called the R
group. Every amino acid has the same amino group, carboxylic acid group, and an alpha
carbon, but the side chain is different.
Question 8
Which pair of amino acids will most likely interact through hydrophobic forces between
their side chains?
A. Serine and Threonine
B. Aspartate and Lysine
C. Alanine and Valine
D. Glutamate and Glutamine
Answer: C
Rationale: Alanine and valine are both nonpolar amino acids and can interact together
with a hydrophobic interaction. The nonpolar side chains of these amino acids are
repelled by water and will cluster together, stabilizing protein structure through
hydrophobic forces.
Question 9
Which portion of the amino acid is indicated by the box in the diagram below?
pg. 3
Complete Practice Questions with Verified
Answers & Rationales | Latest Update
2026/2027 Edition
Question 1
Which level of protein structure is disrupted through the hydrolysis of peptide bonds?
A. Quaternary
B. Tertiary
C. Primary
D. Secondary
Answer: C
Rationale: The primary structure of a protein is the sequence of amino acids held
together by peptide bonds. Peptide bonds are formed by dehydration reactions and
disrupted by hydrolysis.
Question 2
A mutation in the beta-hemoglobin gene, which results in the replacement of the amino
acid glutamate in position 6 with the amino acid valine, leads to the development of
sickle cell anemia. If the beta hemoglobin gene in a patient with sickle-cell anemia were
to be edited so that the valine in position 6 was replaced with a different amino acid,
which replacement for valine would be expected to have the best clinical outcome, in
theory, for the patient?
A. Isoleucine
B. Aspartate
C. Alanine
D. Leucine
Answer: B
Rationale: Glutamate is a charged, polar amino acid. Valine is nonpolar. Replacing
valine with another charged or polar amino acid like aspartate would most likely restore
normal protein folding and function. Isoleucine, alanine, and leucine are all nonpolar
amino acids and would not correct the hydrophobic interaction disruption.
pg. 1
,Question 3
An increase in beta-pleated sheet structure in some brain proteins can lead to an
increase in amyloid deposit formation, characteristic of some neurodegenerative
diseases. What is the primary biochemical process that follows the increase in beta-
pleated sheet structure that leads to the development of the amyloid deposits?
A. An increase in glycogen formation in the brain cells
B. Aggregation of the proteins in the brain
C. Secretion of glucagon, leading to excessive ketogenesis
D. An increase in anaerobic metabolism of glucose in the brain
Answer: B
Rationale: Aggregation occurs when proteins clump together inappropriately, causing
plaques like amyloid deposits to accumulate.
Question 4
Which level of protein structure is determined by the sequence of amino acids?
A. Secondary structure
B. Quaternary structure
C. Tertiary structure
D. Primary structure
Answer: D
Rationale: The primary structure of a protein is simply the sequence of amino acids
held together by peptide bonds.
Question 5
Which force is most influential in determining the secondary structure of a protein?
A. Hydrophobic effect
B. Disulfide bonding
C. Hydrogen bonding
D. Electrostatic interactions
Answer: C
Rationale: The secondary structure of a protein is built by hydrogen bonds between
the carboxyl groups and amino groups on the backbones of the amino acids.
Question 6
Which amino acid shown below would most likely participate in hydrogen bonds?
pg. 2
, A. Structure 1 (CH3-CH2-CH2-CH2-)
B. Structure 2 (HO-CH2-)
C. Structure 3 (CH3-CH2-S-)
D. Structure 4 (CH3-CH2-CH3)
Answer: B
Rationale: The OH group on the side chain makes this a polar, uncharged amino acid.
Polar, uncharged amino acids containing oxygen or NH groups readily form hydrogen
bonds.
Question 7
Which portion of the amino acid is indicated by the box in the diagram below?
A. Amino group
B. Carboxyl group
C. Side Chain (R group)
D. Alpha Carbon
Answer: C
Rationale: The side chain is the variable group of the amino acid, also called the R
group. Every amino acid has the same amino group, carboxylic acid group, and an alpha
carbon, but the side chain is different.
Question 8
Which pair of amino acids will most likely interact through hydrophobic forces between
their side chains?
A. Serine and Threonine
B. Aspartate and Lysine
C. Alanine and Valine
D. Glutamate and Glutamine
Answer: C
Rationale: Alanine and valine are both nonpolar amino acids and can interact together
with a hydrophobic interaction. The nonpolar side chains of these amino acids are
repelled by water and will cluster together, stabilizing protein structure through
hydrophobic forces.
Question 9
Which portion of the amino acid is indicated by the box in the diagram below?
pg. 3
