WGU C785 BIOCHEMISTRY UNIT EXAM(Latest 2026 Update)
/C 785 REAL QUESTIONS AND CORRECT VERIFIED
ANSWERS|ALREADY GRADED A+
Which level of protein structure is determined by the sequence of
amino acids?
Secondary structure
Quaternary structure
Tertiary structure
Primary structure
- Answer -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
- Answer -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?
- Answer -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.
pg. 1
,Which portion of the amino acid is inside the box?
The box is surrounding the section below the Alpha Carbon
- Answer -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?
- Answer -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
- Answer -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
pg. 2
,Hydrogen bond
Hydrophobic interaction - Answer -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
A mutation of the gene for a protein that leads to the substitution of a
hydrophobic amino acid with a nonpolar amino acid
A mutation of the gene for a protein that leads to the substitution of a
nonpolar amino acid with a charged amino acid
The mutation of a gene for an enzyme involved in protein synthesis
following exposure to X-rays, causing the protein not to be
synthesized
- Answer -A mutation of the gene for a protein that leads to the
substitution of a nonpolar amino acid with a charged amino acid.
The mutation of nonpolar amino acid to a charged amino acid will disrupt the
original hydrophobic interaction, permanently changing the function of the
protein.
Which property of enzymes is illustrated in the final step of the
enzymatic cycle?
Enzymes are specific.
Enzymes increase the reaction rate for a reaction.
Enzymes are reusable.
pg. 3
, Enzymes lower the activation energy for a reaction.
- Answer -Enzymes are reusable.
In the final step of the enzymatic cycle, the product is released and the enzyme
is able to bind to a new substrate and begin the cycle again.
In the enzyme cycle, which step immediately follows induced fit?
Formation of the enzyme-substrate complex
Release of the product and enzyme complex
Formation of the enzyme-molecule complex
Formation of the enzyme-product complex
- Answer -Formation of the enzyme-product complex
The induced fit refers to the conformational change that the enzyme undergoes
when it binds to the substrate to form the enzyme-substrate complex. Therefore,
the enzymatic cycle step that occurs after the induced fit is the formation of the
enzyme-product complex.
Which type of inhibition occurs when a particular drug binds to the
active site of an enzyme?
Competitive
Uncompetitive
Irreversible
Noncompetitive - Answer -Competitive
Competitive inhibitors compete with the substrate to bind to the active site of
the enzyme.
Salivary amylase, an enzyme responsible for partial digestion of
carbohydrates, has optimum activity at a pH value of 6.8.
What is the impact on the activity if the pH is decreased to 4.0?
pg. 4
/C 785 REAL QUESTIONS AND CORRECT VERIFIED
ANSWERS|ALREADY GRADED A+
Which level of protein structure is determined by the sequence of
amino acids?
Secondary structure
Quaternary structure
Tertiary structure
Primary structure
- Answer -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
- Answer -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?
- Answer -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.
pg. 1
,Which portion of the amino acid is inside the box?
The box is surrounding the section below the Alpha Carbon
- Answer -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?
- Answer -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
- Answer -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
pg. 2
,Hydrogen bond
Hydrophobic interaction - Answer -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
A mutation of the gene for a protein that leads to the substitution of a
hydrophobic amino acid with a nonpolar amino acid
A mutation of the gene for a protein that leads to the substitution of a
nonpolar amino acid with a charged amino acid
The mutation of a gene for an enzyme involved in protein synthesis
following exposure to X-rays, causing the protein not to be
synthesized
- Answer -A mutation of the gene for a protein that leads to the
substitution of a nonpolar amino acid with a charged amino acid.
The mutation of nonpolar amino acid to a charged amino acid will disrupt the
original hydrophobic interaction, permanently changing the function of the
protein.
Which property of enzymes is illustrated in the final step of the
enzymatic cycle?
Enzymes are specific.
Enzymes increase the reaction rate for a reaction.
Enzymes are reusable.
pg. 3
, Enzymes lower the activation energy for a reaction.
- Answer -Enzymes are reusable.
In the final step of the enzymatic cycle, the product is released and the enzyme
is able to bind to a new substrate and begin the cycle again.
In the enzyme cycle, which step immediately follows induced fit?
Formation of the enzyme-substrate complex
Release of the product and enzyme complex
Formation of the enzyme-molecule complex
Formation of the enzyme-product complex
- Answer -Formation of the enzyme-product complex
The induced fit refers to the conformational change that the enzyme undergoes
when it binds to the substrate to form the enzyme-substrate complex. Therefore,
the enzymatic cycle step that occurs after the induced fit is the formation of the
enzyme-product complex.
Which type of inhibition occurs when a particular drug binds to the
active site of an enzyme?
Competitive
Uncompetitive
Irreversible
Noncompetitive - Answer -Competitive
Competitive inhibitors compete with the substrate to bind to the active site of
the enzyme.
Salivary amylase, an enzyme responsible for partial digestion of
carbohydrates, has optimum activity at a pH value of 6.8.
What is the impact on the activity if the pH is decreased to 4.0?
pg. 4
