WGU C785 BIOCHEMISTRY UNIT EXAM COMPLETE SOLUTION
Which level of protein structure is disrupted through the hydrolysis of peptide bonds?
Quaternary
Tertiary
Primary
Secondary - 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.) - 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 - 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 - 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 - 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 - 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? - 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 - 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? - 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 - 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
Hydrogen bond
Hydrophobic interaction - Hydrophobic interaction
The amino acid pictured only has CH groups in its side chain, and therefore is non-
polar. Non-polar amino acids make hydrophobic interactions.
Which change would most likely result in a permanent modification of an expressed
protein's function?
An increase in the pH of a solution in which a protein is dissolved from 6.5 to 8.0, when
it is known that the protein has an optimal activity of pH 7.8
Which level of protein structure is disrupted through the hydrolysis of peptide bonds?
Quaternary
Tertiary
Primary
Secondary - 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.) - 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 - 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 - 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 - 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 - 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? - 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 - 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? - 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 - 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
Hydrogen bond
Hydrophobic interaction - Hydrophobic interaction
The amino acid pictured only has CH groups in its side chain, and therefore is non-
polar. Non-polar amino acids make hydrophobic interactions.
Which change would most likely result in a permanent modification of an expressed
protein's function?
An increase in the pH of a solution in which a protein is dissolved from 6.5 to 8.0, when
it is known that the protein has an optimal activity of pH 7.8
