WGU C785 FINAL EXAM – 400 UNIQUE MULTIPLE-CHOICE QUESTIONS AND ANSWERS WITH DETAILED RATIONALES LATEST UPDATE 2026

WGU C785 FINAL EXAM – 400 UNIQUE
MULTIPLE-CHOICE QUESTIONS AND
ANSWERS WITH DETAILED RATIONALES
LATEST UPDATE 2026


MODULE 1: Amino Acids, Proteins, and Protein Structure


Topic 1.1: Amino Acid Structure and Properties


Question 1
Which component of an amino acid is responsible for its unique chemical
properties and distinguishes one amino acid from another?
- A) Amino group
- B) Carboxyl group
- C) Alpha carbon
- D) R-group (side chain)


Correct Answer: D


Rationale: The R-group (side chain) is the variable component that differs among
the 20 standard amino acids. The amino group (-NH₂), carboxyl group (-COOH),
and alpha carbon are identical in all amino acids. The side chain determines each
amino acid's size, shape, charge, hydrophobicity, and chemical reactivity,
ultimately dictating the protein's structure and function.



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Question 2
Which type of amino acid side chain would most likely be found in the interior of a
globular protein, away from water?
- A) Polar uncharged
- B) Charged (positive)
- C) Charged (negative)
- D) Nonpolar hydrophobic


Correct Answer: D


Rationale: Nonpolar hydrophobic amino acids (those ending in CH groups) avoid
water and are typically buried in the protein interior. Polar and charged amino
acids are hydrophilic and tend to be on the protein surface where they can interact
with water. This hydrophobic effect is a major driving force for protein folding.


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Question 3
Which type of bond is formed between the amino group of one amino acid and the
carboxyl group of another during protein synthesis?
- A) Hydrogen bond
- B) Ionic bond
- C) Peptide bond
- D) Disulfide bond



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,Correct Answer: C


Rationale: A peptide bond is a covalent bond formed between the carboxyl group
of one amino acid and the amino group of another through a dehydration reaction.
This bond links amino acids together in the primary structure of a protein. Peptide
bonds are strong covalent bonds that require hydrolysis to be broken.


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Question 4
Which amino acid side chain type would most likely participate in hydrogen
bonding with water?
- A) Nonpolar hydrophobic
- B) Polar uncharged with -OH group
- C) Nonpolar with only CH groups
- D) Aromatic hydrophobic


Correct Answer: B


Rationale: Polar uncharged amino acids containing oxygen or NH groups (such as
those with -OH, -SH, or -NH₂ side chains) can form hydrogen bonds with water.
Nonpolar amino acids lack the electronegative atoms needed for hydrogen bonding
and are hydrophobic.


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Question 5


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, A researcher is studying a protein and notices that a mutation has changed a polar
amino acid to a nonpolar amino acid in the protein's interior. What is the most
likely consequence?
- A) No change in protein function
- B) Increased protein solubility
- C) Disruption of protein folding and function
- D) Strengthening of hydrogen bonds


Correct Answer: C


Rationale: Changing a polar amino acid to a nonpolar amino acid in the protein
interior disrupts the original hydrophobic interactions. The protein's 3D structure
depends on proper placement of hydrophobic residues in the interior and polar
residues on the surface. This alteration can permanently change protein function.
Proteins lose form, they lose function.


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Question 6
What is the general structure of an amino acid?
- A) A central carbon bonded to four different groups: amino, carboxyl, hydrogen,
and R-group
- B) A central carbon bonded to two amino groups and two carboxyl groups
- C) A chain of carbons with an amino group at one end and carboxyl at the other
- D) A ring structure containing nitrogen


Correct Answer: A


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