WGU C785
Biochemistry
Unit Exam
Q&A
Latest Version
2021/22
,WGU C785 Biochemistry Unit Exam
Questions
Which level of protein structure is disrupted through the hydrolysis of peptide bonds?
Quaternary
Tertiary
Primary
Secondary
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.
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.)
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
, 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 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
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?
Secondary structure
Quaternary structure
Tertiary structure
Primary structure
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
Biochemistry
Unit Exam
Q&A
Latest Version
2021/22
,WGU C785 Biochemistry Unit Exam
Questions
Which level of protein structure is disrupted through the hydrolysis of peptide bonds?
Quaternary
Tertiary
Primary
Secondary
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.
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.)
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
, 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 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
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?
Secondary structure
Quaternary structure
Tertiary structure
Primary structure
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
