WGU C785 Biochemistry Unit Exam Questions &
Answers
Which level of protein structure is disrupted through the hydrolysis of
peptide bonds?
Quaternary
Tertiary
Primary
Secondary
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
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.)
Correct Ans:-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 Ans:-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
Correct Ans:-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
Correct Ans:-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 Ans:-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?
Correct Ans:-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
Correct Ans:-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?
Correct Ans:-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
Correct Ans:-Alpha Carbon
The alpha carbon is the central carbon on an amino acid that holds together
the other groups of the amino acid. It is always attached to the amino group,
the carboxyl group, the side chain, and a single hydrogen. It is part of the
backbone of the amino acid and is found in every amino acid.
Given the following amino acid structure, what is the strongest
intermolecular force it would participate in to stabilize a protein structure?
Ionic bond
Disulfide bond
Answers
Which level of protein structure is disrupted through the hydrolysis of
peptide bonds?
Quaternary
Tertiary
Primary
Secondary
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
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.)
Correct Ans:-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 Ans:-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
Correct Ans:-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
Correct Ans:-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 Ans:-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?
Correct Ans:-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
Correct Ans:-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?
Correct Ans:-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
Correct Ans:-Alpha Carbon
The alpha carbon is the central carbon on an amino acid that holds together
the other groups of the amino acid. It is always attached to the amino group,
the carboxyl group, the side chain, and a single hydrogen. It is part of the
backbone of the amino acid and is found in every amino acid.
Given the following amino acid structure, what is the strongest
intermolecular force it would participate in to stabilize a protein structure?
Ionic bond
Disulfide bond
