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WGU C785 BIOCHEMISTRY UNIT EXAM
2025 UPDATED ACTUAL EXAM WITH
CORRECT SOLUTIONS.
Which level of protein structure is disrupted through the
hydrolysis of peptide bonds?
Quaternary
Tertiary
Primary
Secondary - correct answer- 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.
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.
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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? (Assume the valine can potentially be replaced with
any amino acid other than glutamate.) - correct answer- 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.
Secondary, tertiary, and quaternary levels of protein structure
can all be impacted by exposing a protein to which treatment?
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 - correct
answer- Placement of the protein in a solution with a low pH
Changes in pH affect hydrogen bonds and ionic bonds.
Hydrogen bonds in the backbone of amino acids occur in
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secondary structure, and both hydrogen bonds and ionic bonds
occur in the side chains of amino acids in tertiary structure.
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?
An increase in glycogen formation in the brain cells
Aggregation of the proteins in the brain
Secretion of glucagon, leading to excessive ketogenesis
An increase in anaerobic metabolism of glucose in the brain -
correct answer- Aggregation of the proteins in the brain
This question is describing changes in protein structure.
Aggregation occurs when proteins clump together
inappropriately, causing plaques like amyloid deposits to
accumulate.
Which level of protein structure is determined by the sequence
of amino acids?
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Secondary structure
Quaternary structure
Tertiary structure
Primary structure - correct answer- Primary structure
The primary structure of a protein is simply the sequence of
amino acids held together by peptide bonds.
Which force is most influential in determining the secondary
structure of a protein?
Hydrophobic effect
Disulfide bonding
Hydrogen bonding
Electrostatic interactions - correct answer- Hydrogen bonding
WGU C785 BIOCHEMISTRY UNIT EXAM
2025 UPDATED ACTUAL EXAM WITH
CORRECT SOLUTIONS.
Which level of protein structure is disrupted through the
hydrolysis of peptide bonds?
Quaternary
Tertiary
Primary
Secondary - correct answer- 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.
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.
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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? (Assume the valine can potentially be replaced with
any amino acid other than glutamate.) - correct answer- 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.
Secondary, tertiary, and quaternary levels of protein structure
can all be impacted by exposing a protein to which treatment?
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 - correct
answer- Placement of the protein in a solution with a low pH
Changes in pH affect hydrogen bonds and ionic bonds.
Hydrogen bonds in the backbone of amino acids occur in
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secondary structure, and both hydrogen bonds and ionic bonds
occur in the side chains of amino acids in tertiary structure.
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?
An increase in glycogen formation in the brain cells
Aggregation of the proteins in the brain
Secretion of glucagon, leading to excessive ketogenesis
An increase in anaerobic metabolism of glucose in the brain -
correct answer- Aggregation of the proteins in the brain
This question is describing changes in protein structure.
Aggregation occurs when proteins clump together
inappropriately, causing plaques like amyloid deposits to
accumulate.
Which level of protein structure is determined by the sequence
of amino acids?
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Secondary structure
Quaternary structure
Tertiary structure
Primary structure - correct answer- Primary structure
The primary structure of a protein is simply the sequence of
amino acids held together by peptide bonds.
Which force is most influential in determining the secondary
structure of a protein?
Hydrophobic effect
Disulfide bonding
Hydrogen bonding
Electrostatic interactions - correct answer- Hydrogen bonding
