WGU C785 Biochemistry Unit Exam
Comprehensive Questions (Frequently
Tested) with Verified Answers Graded A+
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
, Electrostatic interactions - Answer: Hydrogen bonding
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.
Which amino acid would most likely participate in hydrogen bonds? - Answer: Amino Acid
structure 4
This is a polar, uncharged amino acid due to the OH group on the side chain. Polar, uncharged
amino acids containing oxygen or NH groups make hydrogen bonds.
Which portion of the amino acid is inside the box?
The box is surrounding the section below the Alpha Carbon - Answer: Side Chain
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.
Which pair of amino acids will most likely interact through hydrophobic forces between their
side chains? - Answer: Both of these amino acids are non-polar and therefore can interact
together with a hydrophobic interaction. Please note that the "S" in the amino acid on the right
is non-polar, while the "SH" group in answer choice D is polar. The S must have an H to be polar
and is otherwise non-polar.
Which portion of the amino acid is inside the box?
The box is over the Carbon at the Center of the chain - Answer: Alpha Carbon
Comprehensive Questions (Frequently
Tested) with Verified Answers Graded A+
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
, Electrostatic interactions - Answer: Hydrogen bonding
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.
Which amino acid would most likely participate in hydrogen bonds? - Answer: Amino Acid
structure 4
This is a polar, uncharged amino acid due to the OH group on the side chain. Polar, uncharged
amino acids containing oxygen or NH groups make hydrogen bonds.
Which portion of the amino acid is inside the box?
The box is surrounding the section below the Alpha Carbon - Answer: Side Chain
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.
Which pair of amino acids will most likely interact through hydrophobic forces between their
side chains? - Answer: Both of these amino acids are non-polar and therefore can interact
together with a hydrophobic interaction. Please note that the "S" in the amino acid on the right
is non-polar, while the "SH" group in answer choice D is polar. The S must have an H to be polar
and is otherwise non-polar.
Which portion of the amino acid is inside the box?
The box is over the Carbon at the Center of the chain - Answer: Alpha Carbon
