WGU C785 Final Exam 2026 With All The Correct Answers
Actual Exam 2026/2027 | Complete Exam-Style Questions with
Detailed Rationales | 100% Verified | Pass Guaranteed – A+
Graded
Biomolecules and Cellular Chemistry
Q1: A patient presents with bleeding gums and poor wound healing, and their dietary
history reveals a severe lack of fresh fruits and vegetables. Which biochemical modification
is most likely impaired in this patient’s collagen synthesis?
A. Phosphorylation of serine residues
B. Hydroxylation of proline and lysine [CORRECT]
C. Methylation of arginine residues
D. Acetylation of N-terminal glycine
Correct Answer: B
Rationale: The best answer is B because vitamin C is an essential cofactor for prolyl and lysyl
hydroxylase, enzymes required to stabilize the collagen triple helix.
Q2: In a laboratory experiment, a protein is heated to 95°C, causing it to lose its three-
dimensional shape and function, though its amino acid sequence remains intact. Which level
of protein structure is primarily preserved in this scenario?
A. Secondary structure
B. Tertiary structure
C. Primary structure [CORRECT]
D. Quaternary structure
Correct Answer: C
Rationale: This choice is correct because the primary structure is the linear sequence of
amino acids held together by covalent peptide bonds, which are not broken by heat
denaturation.
Q3: A newborn is diagnosed with an inability to digest milk sugars, leading to bloating and
diarrhea. The deficient enzyme normally cleaves which type of chemical bond?
A. Alpha-1,4-glycosidic bond
B. Beta-1,4-glycosidic bond [CORRECT]
C. Alpha-1,6-glycosidic bond
D. Peptide bond
Correct Answer: B
Rationale: The best answer is B because lactase specifically hydrolyzes the beta-1,4-
glycosidic bond linking glucose and galactose in lactose.
Q4: A researcher is studying cell membranes and notes that a specific lipid increases
membrane fluidity at low temperatures due to the presence of cis-double bonds. Which
lipid is being described?
,A. Saturated fatty acid
B. Unsaturated fatty acid [CORRECT]
C. Cholesterol
D. Triglyceride
Correct Answer: B
Rationale: This choice is correct because the kinks introduced by cis-double bonds in
unsaturated fatty acids prevent tight packing, thereby maintaining membrane fluidity in
colder environments.
Q5: A drug is designed to treat hypertension by binding to the active site of angiotensin-
converting enzyme (ACE), preventing the natural substrate from binding. What type of
inhibition does this drug exhibit?
A. Noncompetitive inhibition
B. Competitive inhibition [CORRECT]
C. Allosteric inhibition
D. Irreversible inhibition
Correct Answer: B
Rationale: The best answer is B because competitive inhibitors bind directly to the enzyme's
active site, competing with the substrate and increasing the apparent Km without affecting
Vmax.
Q6: Which of the following best describes the structural difference between DNA and RNA
nucleotides?
A. DNA contains uracil, while RNA contains thymine.
B. DNA contains ribose, while RNA contains deoxyribose.
C. DNA contains deoxyribose, while RNA contains ribose. [CORRECT]
D. DNA is typically single-stranded, while RNA is double-stranded.
Correct Answer: C
Rationale: This aligns with the fundamental biochemical principle that DNA nucleotides
feature a deoxyribose sugar (lacking an oxygen at the 2' carbon), whereas RNA nucleotides
contain a ribose sugar.
Q7: A genetic mutation results in the misfolding of a newly synthesized protein, leading to
its aggregation in the cytoplasm. Which cellular component is most likely failing to assist in
proper protein folding?
A. Ribosome
B. Chaperone protein [CORRECT]
C. Proteasome
D. Lysosome
Correct Answer: B
Rationale: The best answer is B because chaperone proteins, such as heat shock proteins,
are specifically responsible for assisting in the proper three-dimensional folding of nascent
polypeptides.
Q8: During a fasting state, the body breaks down glycogen to maintain blood glucose levels.
Which enzyme is responsible for cleaving the alpha-1,6-glycosidic bonds at the branch
points of glycogen?
, A. Glycogen phosphorylase
B. Debranching enzyme [CORRECT]
C. Glycogen synthase
D. Hexokinase
Correct Answer: B
Rationale: This choice is correct because the debranching enzyme possesses transferase and
glucosidase activities necessary to remove the alpha-1,6 branches during glycogenolysis.
Q9: Phospholipids are the primary structural components of the cell membrane. Which of
the following best describes their chemical nature?
A. Completely hydrophobic
B. Completely hydrophilic
C. Amphipathic [CORRECT]
D. Nonpolar
Correct Answer: C
Rationale: The best answer is C because phospholipids contain a hydrophilic phosphate
head and hydrophobic fatty acid tails, allowing them to form stable bilayers in aqueous
environments.
Q10: A patient with a poor diet develops night blindness. This condition is linked to a
deficiency in a vitamin that serves as a precursor for retinal. This vitamin is classified as:
A. Water-soluble
B. Fat-soluble [CORRECT]
C. Amino acid-derived
D. A mineral cofactor
Correct Answer: B
Rationale: This matches the principle that vitamin A is a fat-soluble vitamin essential for the
synthesis of retinal, a critical component of the visual pigment rhodopsin.
Q11: Which of the following amino acids must be obtained directly from the diet because
the human body cannot synthesize it?
A. Alanine
B. Leucine [CORRECT]
C. Glutamine
D. Aspartate
Correct Answer: B
Rationale: The best answer is B because leucine is an essential amino acid, meaning it lacks a
corresponding biosynthetic pathway in humans and must be acquired through dietary
protein.
Q12: In an alpha-helix, the secondary structure of a protein is primarily stabilized by which
type of interaction?
A. Disulfide bonds between cysteine residues
B. Hydrogen bonds between backbone amide and carbonyl groups [CORRECT]
C. Hydrophobic interactions between R-groups
D. Ionic bonds between acidic and basic side chains
Correct Answer: B
Actual Exam 2026/2027 | Complete Exam-Style Questions with
Detailed Rationales | 100% Verified | Pass Guaranteed – A+
Graded
Biomolecules and Cellular Chemistry
Q1: A patient presents with bleeding gums and poor wound healing, and their dietary
history reveals a severe lack of fresh fruits and vegetables. Which biochemical modification
is most likely impaired in this patient’s collagen synthesis?
A. Phosphorylation of serine residues
B. Hydroxylation of proline and lysine [CORRECT]
C. Methylation of arginine residues
D. Acetylation of N-terminal glycine
Correct Answer: B
Rationale: The best answer is B because vitamin C is an essential cofactor for prolyl and lysyl
hydroxylase, enzymes required to stabilize the collagen triple helix.
Q2: In a laboratory experiment, a protein is heated to 95°C, causing it to lose its three-
dimensional shape and function, though its amino acid sequence remains intact. Which level
of protein structure is primarily preserved in this scenario?
A. Secondary structure
B. Tertiary structure
C. Primary structure [CORRECT]
D. Quaternary structure
Correct Answer: C
Rationale: This choice is correct because the primary structure is the linear sequence of
amino acids held together by covalent peptide bonds, which are not broken by heat
denaturation.
Q3: A newborn is diagnosed with an inability to digest milk sugars, leading to bloating and
diarrhea. The deficient enzyme normally cleaves which type of chemical bond?
A. Alpha-1,4-glycosidic bond
B. Beta-1,4-glycosidic bond [CORRECT]
C. Alpha-1,6-glycosidic bond
D. Peptide bond
Correct Answer: B
Rationale: The best answer is B because lactase specifically hydrolyzes the beta-1,4-
glycosidic bond linking glucose and galactose in lactose.
Q4: A researcher is studying cell membranes and notes that a specific lipid increases
membrane fluidity at low temperatures due to the presence of cis-double bonds. Which
lipid is being described?
,A. Saturated fatty acid
B. Unsaturated fatty acid [CORRECT]
C. Cholesterol
D. Triglyceride
Correct Answer: B
Rationale: This choice is correct because the kinks introduced by cis-double bonds in
unsaturated fatty acids prevent tight packing, thereby maintaining membrane fluidity in
colder environments.
Q5: A drug is designed to treat hypertension by binding to the active site of angiotensin-
converting enzyme (ACE), preventing the natural substrate from binding. What type of
inhibition does this drug exhibit?
A. Noncompetitive inhibition
B. Competitive inhibition [CORRECT]
C. Allosteric inhibition
D. Irreversible inhibition
Correct Answer: B
Rationale: The best answer is B because competitive inhibitors bind directly to the enzyme's
active site, competing with the substrate and increasing the apparent Km without affecting
Vmax.
Q6: Which of the following best describes the structural difference between DNA and RNA
nucleotides?
A. DNA contains uracil, while RNA contains thymine.
B. DNA contains ribose, while RNA contains deoxyribose.
C. DNA contains deoxyribose, while RNA contains ribose. [CORRECT]
D. DNA is typically single-stranded, while RNA is double-stranded.
Correct Answer: C
Rationale: This aligns with the fundamental biochemical principle that DNA nucleotides
feature a deoxyribose sugar (lacking an oxygen at the 2' carbon), whereas RNA nucleotides
contain a ribose sugar.
Q7: A genetic mutation results in the misfolding of a newly synthesized protein, leading to
its aggregation in the cytoplasm. Which cellular component is most likely failing to assist in
proper protein folding?
A. Ribosome
B. Chaperone protein [CORRECT]
C. Proteasome
D. Lysosome
Correct Answer: B
Rationale: The best answer is B because chaperone proteins, such as heat shock proteins,
are specifically responsible for assisting in the proper three-dimensional folding of nascent
polypeptides.
Q8: During a fasting state, the body breaks down glycogen to maintain blood glucose levels.
Which enzyme is responsible for cleaving the alpha-1,6-glycosidic bonds at the branch
points of glycogen?
, A. Glycogen phosphorylase
B. Debranching enzyme [CORRECT]
C. Glycogen synthase
D. Hexokinase
Correct Answer: B
Rationale: This choice is correct because the debranching enzyme possesses transferase and
glucosidase activities necessary to remove the alpha-1,6 branches during glycogenolysis.
Q9: Phospholipids are the primary structural components of the cell membrane. Which of
the following best describes their chemical nature?
A. Completely hydrophobic
B. Completely hydrophilic
C. Amphipathic [CORRECT]
D. Nonpolar
Correct Answer: C
Rationale: The best answer is C because phospholipids contain a hydrophilic phosphate
head and hydrophobic fatty acid tails, allowing them to form stable bilayers in aqueous
environments.
Q10: A patient with a poor diet develops night blindness. This condition is linked to a
deficiency in a vitamin that serves as a precursor for retinal. This vitamin is classified as:
A. Water-soluble
B. Fat-soluble [CORRECT]
C. Amino acid-derived
D. A mineral cofactor
Correct Answer: B
Rationale: This matches the principle that vitamin A is a fat-soluble vitamin essential for the
synthesis of retinal, a critical component of the visual pigment rhodopsin.
Q11: Which of the following amino acids must be obtained directly from the diet because
the human body cannot synthesize it?
A. Alanine
B. Leucine [CORRECT]
C. Glutamine
D. Aspartate
Correct Answer: B
Rationale: The best answer is B because leucine is an essential amino acid, meaning it lacks a
corresponding biosynthetic pathway in humans and must be acquired through dietary
protein.
Q12: In an alpha-helix, the secondary structure of a protein is primarily stabilized by which
type of interaction?
A. Disulfide bonds between cysteine residues
B. Hydrogen bonds between backbone amide and carbonyl groups [CORRECT]
C. Hydrophobic interactions between R-groups
D. Ionic bonds between acidic and basic side chains
Correct Answer: B
