Biochemistry WGU Questions And
Detailed Answers
,Which level of protein structure is disrupted through the hydrolysis of peptide bonds - CORRECT
ANS:primary - The primary structure of a protein is the sequence of amino acids held together by
peptide bonds. Peptide bonds are formed by dehydration and disrupted 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 an amino acid other than glutamate.) - CORRECT ANS:Valine is what is causing sickle cell anemia.
The best answer is to be to pick the structure that looks most like the Glutamate r group
Secondary, tertiary, and quaternary levels of protein structure can all be impacted by exposing a protein
to which treatment? - CORRECT ANS:Placement of the protein in a solution with a low pH
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? - CORRECT ANS:Aggregation of the proteins in the brain
Which level of protein structure is determined by the sequence of amino acids? - CORRECT ANS:Primary
structure - simply the sequence of amino acids held together by peptide bonds
Which force is most influential in determining the secondary structure of a protein? - CORRECT
ANS:Hydrogen bonding - the secondary structure of a protein is built by hydrogen bonds between the
carboxyl groups and the amino groups on the backbones of the amino acids
Which amino acid would most likely participate in hydrogen bonds? - CORRECT ANS:Polar amino acid
(OH)
,Which portion of the amino acid is inside the box? - CORRECT ANS:side chain
Which pair of amino acids will most likely interact through hydrophobic forces between their side
chains? - CORRECT ANS:these amino acids are non polar and therefore interact together with a
hydrophobic interaction
Which portion of the amino acid is inside the box? - CORRECT ANS:alpha carbon
Given the following amino acid structure, what is the strongest intermolecular force it would participate
in to stabilize a protein structure? - CORRECT ANS:hydrophobic interaction
Which change would most likely result in a permanent modification of an expressed protein's function? -
CORRECT ANS:A mutation of the gene for a protein that leads to the substitution of a nonpolar amino
acid with a charged amino acid
Which kind of interaction can the following pair of amino acids form between their side chains (R-
groups)? - CORRECT ANS:Hydrogen bonds are made between R groups that have polar bonds within
them N-H, O-H, C-O or C-N but do not display a visible charge (+/-) on their R group.
Which bond or interaction can the R group of this amino acid form to stabilize tertiary structure? -
CORRECT ANS:Cysteine can form a disulfide bond with its terminal S-H.
A missense mutation resulting in a change from asparagine to leucine at a specific position on an
enzyme leads to a neurodegenerative disease.
Is there an alternate amino acid substitution of a missense mutation listed below that would have less of
an impact on the protein structure and consequently its function than the proposed leucine substitution
would? - CORRECT ANS:Glutamine is a polar amino acid and the amino acid asparagine is a polar amino
acid, which contain C-N, C-O, O-H or N-H bonds on the outside surface of their R groups. The most likely
replacement for a polar amino acid that would have less of an impact on protein structure would be
another polar amino acid.
, Choose the answer that correctly labels the amino group, the carboxyl group, and the variable group on
the amino acid from the image: - CORRECT ANS:A-variable group, B-amino group, C-carboxyl group
Which characteristic correctly describes the amino acid image? - CORRECT ANS:Non-polar amino acids
have R groups with C-H bonds.
Which of the following interactions can occur between two positively charged amino acids? - CORRECT
ANS:None of these - Two positively charged amino acids would repel each other. Only opposite charges
attract.
Antibodies that enable our body to fight bacterial infections must bind to antigens on the surface of the
bacterial cell. If the antigen on the surface of the bacterial cell has several negatively charged amino
acids, which of the following amino acids would you expect to find on the portion of the antibody that
binds to the antigen? - CORRECT ANS:Positive charged amino acids will be attracted to the negatively
charged amino acids.
What category does this amino acid belong to? - CORRECT ANS:polar, charged - The amino acid depicted
is charged. There is a COO- group displayed as the R group of this amino acid with a visible charge.
This amino acid is polar. True or False - CORRECT ANS:Correct! The amino acid depicted in this problem
is polar/hydrophilic because the end of the amino acid R group has an oxygen bound to a hydrogen.
Other polar amino acids can have nitrogen bound to hydrogen, carbons bound to oxygens or carbons
bound to nitrogens.
This amino acid would prefer to interact with oil over water. True or False - CORRECT ANS:False The
amino acid depicted in this problem is polar/hydrophilic because the end of the amino acid R group has
a nitrogen bound to a hydrogen. Other polar amino acids can have oxygen bound to hydrogen, carbons
bound to oxygens or carbons bound to nitrogens. Water is also polar, and that is why this amino acid
would like to interact with water. And, why the amino acid is categorized as hydrophilic (water loving).
Oils are nonpolar and polar amino acids don't like nonpolar molecules.
Which of the following best describes the nature of protein primary structure? - CORRECT ANS:Amino
acids linked together in a specific order by peptide bonds
Detailed Answers
,Which level of protein structure is disrupted through the hydrolysis of peptide bonds - CORRECT
ANS:primary - The primary structure of a protein is the sequence of amino acids held together by
peptide bonds. Peptide bonds are formed by dehydration and disrupted 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 an amino acid other than glutamate.) - CORRECT ANS:Valine is what is causing sickle cell anemia.
The best answer is to be to pick the structure that looks most like the Glutamate r group
Secondary, tertiary, and quaternary levels of protein structure can all be impacted by exposing a protein
to which treatment? - CORRECT ANS:Placement of the protein in a solution with a low pH
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? - CORRECT ANS:Aggregation of the proteins in the brain
Which level of protein structure is determined by the sequence of amino acids? - CORRECT ANS:Primary
structure - simply the sequence of amino acids held together by peptide bonds
Which force is most influential in determining the secondary structure of a protein? - CORRECT
ANS:Hydrogen bonding - the secondary structure of a protein is built by hydrogen bonds between the
carboxyl groups and the amino groups on the backbones of the amino acids
Which amino acid would most likely participate in hydrogen bonds? - CORRECT ANS:Polar amino acid
(OH)
,Which portion of the amino acid is inside the box? - CORRECT ANS:side chain
Which pair of amino acids will most likely interact through hydrophobic forces between their side
chains? - CORRECT ANS:these amino acids are non polar and therefore interact together with a
hydrophobic interaction
Which portion of the amino acid is inside the box? - CORRECT ANS:alpha carbon
Given the following amino acid structure, what is the strongest intermolecular force it would participate
in to stabilize a protein structure? - CORRECT ANS:hydrophobic interaction
Which change would most likely result in a permanent modification of an expressed protein's function? -
CORRECT ANS:A mutation of the gene for a protein that leads to the substitution of a nonpolar amino
acid with a charged amino acid
Which kind of interaction can the following pair of amino acids form between their side chains (R-
groups)? - CORRECT ANS:Hydrogen bonds are made between R groups that have polar bonds within
them N-H, O-H, C-O or C-N but do not display a visible charge (+/-) on their R group.
Which bond or interaction can the R group of this amino acid form to stabilize tertiary structure? -
CORRECT ANS:Cysteine can form a disulfide bond with its terminal S-H.
A missense mutation resulting in a change from asparagine to leucine at a specific position on an
enzyme leads to a neurodegenerative disease.
Is there an alternate amino acid substitution of a missense mutation listed below that would have less of
an impact on the protein structure and consequently its function than the proposed leucine substitution
would? - CORRECT ANS:Glutamine is a polar amino acid and the amino acid asparagine is a polar amino
acid, which contain C-N, C-O, O-H or N-H bonds on the outside surface of their R groups. The most likely
replacement for a polar amino acid that would have less of an impact on protein structure would be
another polar amino acid.
, Choose the answer that correctly labels the amino group, the carboxyl group, and the variable group on
the amino acid from the image: - CORRECT ANS:A-variable group, B-amino group, C-carboxyl group
Which characteristic correctly describes the amino acid image? - CORRECT ANS:Non-polar amino acids
have R groups with C-H bonds.
Which of the following interactions can occur between two positively charged amino acids? - CORRECT
ANS:None of these - Two positively charged amino acids would repel each other. Only opposite charges
attract.
Antibodies that enable our body to fight bacterial infections must bind to antigens on the surface of the
bacterial cell. If the antigen on the surface of the bacterial cell has several negatively charged amino
acids, which of the following amino acids would you expect to find on the portion of the antibody that
binds to the antigen? - CORRECT ANS:Positive charged amino acids will be attracted to the negatively
charged amino acids.
What category does this amino acid belong to? - CORRECT ANS:polar, charged - The amino acid depicted
is charged. There is a COO- group displayed as the R group of this amino acid with a visible charge.
This amino acid is polar. True or False - CORRECT ANS:Correct! The amino acid depicted in this problem
is polar/hydrophilic because the end of the amino acid R group has an oxygen bound to a hydrogen.
Other polar amino acids can have nitrogen bound to hydrogen, carbons bound to oxygens or carbons
bound to nitrogens.
This amino acid would prefer to interact with oil over water. True or False - CORRECT ANS:False The
amino acid depicted in this problem is polar/hydrophilic because the end of the amino acid R group has
a nitrogen bound to a hydrogen. Other polar amino acids can have oxygen bound to hydrogen, carbons
bound to oxygens or carbons bound to nitrogens. Water is also polar, and that is why this amino acid
would like to interact with water. And, why the amino acid is categorized as hydrophilic (water loving).
Oils are nonpolar and polar amino acids don't like nonpolar molecules.
Which of the following best describes the nature of protein primary structure? - CORRECT ANS:Amino
acids linked together in a specific order by peptide bonds
