1
WGU C785 BIOCHEMISTRY UNIT 2025-26 EXAM QUESTIONS AND
ANSWERS WITH RATIONALES
1. Which level of protein structure is disrupted through the hydrolysis of peptide bonds?
Quaternary Tertiary
Primary
Secondary: Primary
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.
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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. The structures of glutamate
and valine are shown below.
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 clin-
ical outcome, in theory, for the patient? (Assume the valine can potentially be replaced with any amino acid other
than glutamate.): The original amino acid in a healthy patient is glutamate, which is negatively charged. The mutated
amino acid is valine, which is non-polar. Valine is causing sickle cell anemia. The best amino acid to replace valine so
that the patient is healthy again would be the one most like glutamate, so any negatively charged amino acid.
3. Secondary, tertiary, and quaternary levels of protein structure can all be impacted by exposing a protein to
which treatment?
,3
Change of a hydrophobic amino acid to a different hydrophobic amino acid Addition of a reducing agent
Placement of the protein in a solution with a low pH
Increase in the concentration of the protein in solution: Placement of the
,4
WGU C785 BIOCHEMISTRY UNIT 2025-26 EXAM QUESTIONS AND
ANSWERS WITH RATIONALES
1. Which level of protein structure is disrupted through the hydrolysis of peptide bonds?
Quaternary Tertiary
Primary
Secondary: Primary
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.
,2
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. The structures of glutamate
and valine are shown below.
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 clin-
ical outcome, in theory, for the patient? (Assume the valine can potentially be replaced with any amino acid other
than glutamate.): The original amino acid in a healthy patient is glutamate, which is negatively charged. The mutated
amino acid is valine, which is non-polar. Valine is causing sickle cell anemia. The best amino acid to replace valine so
that the patient is healthy again would be the one most like glutamate, so any negatively charged amino acid.
3. Secondary, tertiary, and quaternary levels of protein structure can all be impacted by exposing a protein to
which treatment?
,3
Change of a hydrophobic amino acid to a different hydrophobic amino acid Addition of a reducing agent
Placement of the protein in a solution with a low pH
Increase in the concentration of the protein in solution: Placement of the
,4
