WGU 785 FINAL EXAM QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A |
INSTANT DOWNLOAD PDF
CORE DOMAINS
- Protein Structure and Function
*- Enzyme Kinetics and Regulation*
*- Carbohydrate Metabolism*
*- Lipid Metabolism and Biochemistry*
*- Protein Metabolism and Amino Acids*
*- DNA and RNA Biochemistry*
*- Molecular Genetics and Gene Expression*
*- Biochemical Techniques and Analysis*
*- Clinical Biochemistry and Diagnostics*
*- Bioenergetics and Oxidative Phosphorylation*
Introduction
This comprehensive assessment evaluates mastery of fundamental and applied biochemistry concepts essential for professional practice in
healthcare, research, and clinical laboratories. The exam assesses knowledge of molecular structures, metabolic pathways, enzyme mechanisms,
genetic processes, and their real-world applications in diagnosis and treatment. Questions are presented in multiple-choice format with scenario-
based problems that emphasize critical thinking, clinical decision-making, and the integration of biochemical principles to solve complex problems.
Success requires understanding not only theoretical foundations but also how biochemical knowledge translates to practical applications in
medicine, nutrition, pharmacology, and biotechnology.
SECTION ONE: QUESTIONS 1–100
Question 1
,Which level of protein structure is determined primarily by hydrogen bonding between the carbonyl oxygen and amide hydrogen atoms in the
peptide backbone?
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
🟢 B. Secondary structure
🔴 RATIONALE: Secondary structure (alpha helices and beta sheets) is stabilized by hydrogen bonding between backbone atoms (carbonyl oxygen
and amide hydrogen), not by interactions between side chains. Primary structure is the amino acid sequence, tertiary involves side chain
interactions, and quatern涉及 multiple polypeptide chains.
Question 2
A patient presents with fatigue, jaundice, and elevated liver enzymes. Laboratory tests show increased indirect bilirubin. Which biochemical process
is most likely impaired?
A. Hemoglobin synthesis
B. Bilirubin conjugation
C. Iron absorption
D. Vitamin K metabolism
🟢 B. Bilirubin conjugation
🔴 RATIONALE: Elevated indirect (unconjugated) bilirubin with jaundice indicates impaired conjugation in the liver, as seen in conditions like
Gilbert syndrome. Conjugated bilirubin would be elevated if there was excretion impairment.
Question 3
Which amino acid is both glucogenic and ketogenic?
,A. Leucine
B. Lysine
C. Isoleucine
D. Phenylalanine
🟢 D. Phenylalanine
🔴 RATIONALE: Phenylalanine is both glucogenic and ketogenic. Leucine and lysine are exclusively ketogenic. Isoleucine is both glucogenic and
ketogenic as well, but phenylalanine is the more commonly tested example.
Question 4
In the Michaelis-Menten equation, what does Km represent?
A. Maximum reaction velocity
B. Substrate concentration at half Vmax
C. Enzyme concentration
D. Reaction rate constant
🟢 B. Substrate concentration at half Vmax
🔴 RATIONALE: Km (Michaelis constant) is the substrate concentration at which the reaction velocity is half of Vmax. It indicates enzyme affinity
for substrate—lower Km means higher affinity.
Question 5
Which enzyme is defective in alkaptonuria?
A. Homoκogenate oxidase
B. Tyrosinase
C. Phenylalanine hydroxylase
D. Cystathionine synthase
🟢 A. Homoκogenate oxidase
, 🔴 RATIONALE: Alkaptonuria is caused by deficiency of homogentisate oxidase, leading to accumulation of homogentisic acid which causes dark
urine and joint problems.
Question 6
What is the primary storage form of glucose in animals?
A. Starch
B. Glycogen
C. Sucrose
D. Cellulose
🟢 B. Glycogen
🔴 RATIONALE: Glycogen is the primary glucose storage form in animals, stored mainly in liver and muscle. Starch is the plant storage form.
Question 7
Which vitamin is required for the carboxylation of glutamate residues in clotting factors?
A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin K
🟢 D. Vitamin K
🔴 RATIONALE: Vitamin K is required for γ-carboxylation of glutamate residues in clotting factors II, VII, IX, and X, enabling calcium binding and
proper function.
Question 8
In DNA replication, which enzyme removes RNA primers and replaces them with DNA?
INSTANT DOWNLOAD PDF
CORE DOMAINS
- Protein Structure and Function
*- Enzyme Kinetics and Regulation*
*- Carbohydrate Metabolism*
*- Lipid Metabolism and Biochemistry*
*- Protein Metabolism and Amino Acids*
*- DNA and RNA Biochemistry*
*- Molecular Genetics and Gene Expression*
*- Biochemical Techniques and Analysis*
*- Clinical Biochemistry and Diagnostics*
*- Bioenergetics and Oxidative Phosphorylation*
Introduction
This comprehensive assessment evaluates mastery of fundamental and applied biochemistry concepts essential for professional practice in
healthcare, research, and clinical laboratories. The exam assesses knowledge of molecular structures, metabolic pathways, enzyme mechanisms,
genetic processes, and their real-world applications in diagnosis and treatment. Questions are presented in multiple-choice format with scenario-
based problems that emphasize critical thinking, clinical decision-making, and the integration of biochemical principles to solve complex problems.
Success requires understanding not only theoretical foundations but also how biochemical knowledge translates to practical applications in
medicine, nutrition, pharmacology, and biotechnology.
SECTION ONE: QUESTIONS 1–100
Question 1
,Which level of protein structure is determined primarily by hydrogen bonding between the carbonyl oxygen and amide hydrogen atoms in the
peptide backbone?
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. Quaternary structure
🟢 B. Secondary structure
🔴 RATIONALE: Secondary structure (alpha helices and beta sheets) is stabilized by hydrogen bonding between backbone atoms (carbonyl oxygen
and amide hydrogen), not by interactions between side chains. Primary structure is the amino acid sequence, tertiary involves side chain
interactions, and quatern涉及 multiple polypeptide chains.
Question 2
A patient presents with fatigue, jaundice, and elevated liver enzymes. Laboratory tests show increased indirect bilirubin. Which biochemical process
is most likely impaired?
A. Hemoglobin synthesis
B. Bilirubin conjugation
C. Iron absorption
D. Vitamin K metabolism
🟢 B. Bilirubin conjugation
🔴 RATIONALE: Elevated indirect (unconjugated) bilirubin with jaundice indicates impaired conjugation in the liver, as seen in conditions like
Gilbert syndrome. Conjugated bilirubin would be elevated if there was excretion impairment.
Question 3
Which amino acid is both glucogenic and ketogenic?
,A. Leucine
B. Lysine
C. Isoleucine
D. Phenylalanine
🟢 D. Phenylalanine
🔴 RATIONALE: Phenylalanine is both glucogenic and ketogenic. Leucine and lysine are exclusively ketogenic. Isoleucine is both glucogenic and
ketogenic as well, but phenylalanine is the more commonly tested example.
Question 4
In the Michaelis-Menten equation, what does Km represent?
A. Maximum reaction velocity
B. Substrate concentration at half Vmax
C. Enzyme concentration
D. Reaction rate constant
🟢 B. Substrate concentration at half Vmax
🔴 RATIONALE: Km (Michaelis constant) is the substrate concentration at which the reaction velocity is half of Vmax. It indicates enzyme affinity
for substrate—lower Km means higher affinity.
Question 5
Which enzyme is defective in alkaptonuria?
A. Homoκogenate oxidase
B. Tyrosinase
C. Phenylalanine hydroxylase
D. Cystathionine synthase
🟢 A. Homoκogenate oxidase
, 🔴 RATIONALE: Alkaptonuria is caused by deficiency of homogentisate oxidase, leading to accumulation of homogentisic acid which causes dark
urine and joint problems.
Question 6
What is the primary storage form of glucose in animals?
A. Starch
B. Glycogen
C. Sucrose
D. Cellulose
🟢 B. Glycogen
🔴 RATIONALE: Glycogen is the primary glucose storage form in animals, stored mainly in liver and muscle. Starch is the plant storage form.
Question 7
Which vitamin is required for the carboxylation of glutamate residues in clotting factors?
A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin K
🟢 D. Vitamin K
🔴 RATIONALE: Vitamin K is required for γ-carboxylation of glutamate residues in clotting factors II, VII, IX, and X, enabling calcium binding and
proper function.
Question 8
In DNA replication, which enzyme removes RNA primers and replaces them with DNA?
