WGU C785 Biochemistry Unit Exam Questions
And Answers, 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?
And Answers, 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?
