NR 503 Midterm Exam Questions and
Answers (2026) | Complete Midterm
Review Pack | Verified Q&A | A+
• 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 acidAddition
of a reducing agentPlacement of the protein in a solution with a low
pHIncrease 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?
Answers (2026) | Complete Midterm
Review Pack | Verified Q&A | A+
• 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 acidAddition
of a reducing agentPlacement of the protein in a solution with a low
pHIncrease 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?
