BIOCHEM MURPHY EXAM 3 QUESTIONS AND CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES
2026 Q&A |LATEST EXAM UPDATE 2026/2027.
Core Domains
1. Protein Structure and Function
2. Enzyme Kinetics and Mechanisms
3. Carbohydrate Metabolism (Glycolysis, Gluconeogenesis, Pentose Phosphate Pathway)
4. Lipid Metabolism (Beta-Oxidation, Lipogenesis, Ketogenesis)
5. Citric Acid Cycle and Oxidative Phosphorylation
6. Amino Acid and Nucleotide Metabolism
7. Hormonal Regulation and Signaling
8. Metabolic Integration and Organ Specialization
9. Nutrition and Metabolic Disorders
10. Molecular Genetics and Gene Expression
Introduction
This comprehensive examination is designed to rigorously assess your understanding of core biochemical principles
essential for advanced study and professional practice. You will be evaluated on foundational theory, applied
knowledge of metabolic pathways, and the ability to make critical decisions in clinical and research contexts. The
exam consists of multiple-choice questions, including scenario-based items that require you to integrate
information, apply regulatory concepts, and analyze diagnostic data. Emphasis is placed on real-world application,
ethical considerations, and the problem-solving skills necessary for success in the biochemical sciences. This
assessment serves as a definitive tool to confirm your mastery of the subject matter and readiness for future
academic and professional challenges.
,SECTION ONE: QUESTIONS 1–100
1. In a patient with a defect in pyruvate dehydrogenase, which of the following would be a direct
consequence of this deficiency?
A. Increased conversion of pyruvate to alanine
B. Accumulation of lactate and a decreased NADH/NAD+ ratio
C. Enhanced flux through the Citric Acid Cycle
D. Elevated levels of acetyl-CoA
🟢 B. Accumulation of lactate and a decreased NADH/NAD+ ratio
🔴 RATIONALE: Pyruvate dehydrogenase (PDH) converts pyruvate to acetyl-CoA, producing NADH. A defect in
PDH prevents this reaction, shunting pyruvate to lactate, which regenerates NAD+ from NADH, decreasing the
NADH/NAD+ ratio.
2. Which of the following describes the primary function of the pentose phosphate pathway?
A. Generate ATP from glucose
B. Produce NADPH and ribose-5-phosphate
C. Synthesize glycogen from glucose
D. Convert fructose-6-phosphate to glucose-6-phosphate
🟢 B. Produce NADPH and ribose-5-phosphate
,🔴 RATIONALE: The pentose phosphate pathway's primary roles are to generate NADPH for reductive
biosynthesis and to produce ribose-5-phosphate for nucleotide synthesis.
3. A researcher is studying the effect of a non-competitive inhibitor on an enzyme. Which of the following
observations would confirm this mechanism of action?
A. An increase in Vmax with no change in Km
B. A decrease in Vmax with no change in Km
C. An increase in Km with no change in Vmax
D. A decrease in both Vmax and Km
🟢 B. A decrease in Vmax with no change in Km
🔴 RATIONALE: Non-competitive inhibitors bind to an allosteric site, reducing the enzyme's catalytic efficiency
(Vmax) without affecting substrate binding affinity (Km).
4. A 45-year-old patient is diagnosed with a deficiency in glucose-6-phosphatase. Which of the following
metabolic conditions is most likely to be observed?
A. Hyperglycemia and high glycogen stores in the liver
B. Hypoglycemia and hepatomegaly
C. Ketoacidosis and hyperglycemia
D. Normal blood glucose and elevated muscle glycogen
🟢 B. Hypoglycemia and hepatomegaly
🔴 RATIONALE: Glucose-6-phosphatase is essential for gluconeogenesis and glycogenolysis to release free
glucose into the blood. A deficiency causes severe hypoglycemia and accumulation of glycogen in the liver,
, leading to hepatomegaly (Von Gierke disease).
5. The binding of a hormone to its receptor on the cell surface initiates a cascade of events. In the case of
glucagon, which of the following is the immediate downstream effector that leads to protein kinase A
activation?
A. Phospholipase C
B. Receptor tyrosine kinase
C. Adenylyl cyclase
D. Guanylate cyclase
🟢 C. Adenylyl cyclase
🔴 RATIONALE: Glucagon binds to a G-protein coupled receptor that activates adenylyl cyclase, which converts
ATP to cAMP. cAMP then activates Protein Kinase A (PKA).
6. During fatty acid oxidation, which of the following is a direct product of the beta-oxidation spiral that
enters the citric acid cycle?
A. Acetyl-CoA
B. Malonyl-CoA
C. Fatty acyl-CoA
D. Glycerol-3-phosphate
🟢 A. Acetyl-CoA
🔴 RATIONALE: Beta-oxidation cleaves two-carbon units from a fatty acyl-CoA chain, producing acetyl-CoA.
This acetyl-CoA then enters the citric acid cycle for complete oxidation.
2026 Q&A |LATEST EXAM UPDATE 2026/2027.
Core Domains
1. Protein Structure and Function
2. Enzyme Kinetics and Mechanisms
3. Carbohydrate Metabolism (Glycolysis, Gluconeogenesis, Pentose Phosphate Pathway)
4. Lipid Metabolism (Beta-Oxidation, Lipogenesis, Ketogenesis)
5. Citric Acid Cycle and Oxidative Phosphorylation
6. Amino Acid and Nucleotide Metabolism
7. Hormonal Regulation and Signaling
8. Metabolic Integration and Organ Specialization
9. Nutrition and Metabolic Disorders
10. Molecular Genetics and Gene Expression
Introduction
This comprehensive examination is designed to rigorously assess your understanding of core biochemical principles
essential for advanced study and professional practice. You will be evaluated on foundational theory, applied
knowledge of metabolic pathways, and the ability to make critical decisions in clinical and research contexts. The
exam consists of multiple-choice questions, including scenario-based items that require you to integrate
information, apply regulatory concepts, and analyze diagnostic data. Emphasis is placed on real-world application,
ethical considerations, and the problem-solving skills necessary for success in the biochemical sciences. This
assessment serves as a definitive tool to confirm your mastery of the subject matter and readiness for future
academic and professional challenges.
,SECTION ONE: QUESTIONS 1–100
1. In a patient with a defect in pyruvate dehydrogenase, which of the following would be a direct
consequence of this deficiency?
A. Increased conversion of pyruvate to alanine
B. Accumulation of lactate and a decreased NADH/NAD+ ratio
C. Enhanced flux through the Citric Acid Cycle
D. Elevated levels of acetyl-CoA
🟢 B. Accumulation of lactate and a decreased NADH/NAD+ ratio
🔴 RATIONALE: Pyruvate dehydrogenase (PDH) converts pyruvate to acetyl-CoA, producing NADH. A defect in
PDH prevents this reaction, shunting pyruvate to lactate, which regenerates NAD+ from NADH, decreasing the
NADH/NAD+ ratio.
2. Which of the following describes the primary function of the pentose phosphate pathway?
A. Generate ATP from glucose
B. Produce NADPH and ribose-5-phosphate
C. Synthesize glycogen from glucose
D. Convert fructose-6-phosphate to glucose-6-phosphate
🟢 B. Produce NADPH and ribose-5-phosphate
,🔴 RATIONALE: The pentose phosphate pathway's primary roles are to generate NADPH for reductive
biosynthesis and to produce ribose-5-phosphate for nucleotide synthesis.
3. A researcher is studying the effect of a non-competitive inhibitor on an enzyme. Which of the following
observations would confirm this mechanism of action?
A. An increase in Vmax with no change in Km
B. A decrease in Vmax with no change in Km
C. An increase in Km with no change in Vmax
D. A decrease in both Vmax and Km
🟢 B. A decrease in Vmax with no change in Km
🔴 RATIONALE: Non-competitive inhibitors bind to an allosteric site, reducing the enzyme's catalytic efficiency
(Vmax) without affecting substrate binding affinity (Km).
4. A 45-year-old patient is diagnosed with a deficiency in glucose-6-phosphatase. Which of the following
metabolic conditions is most likely to be observed?
A. Hyperglycemia and high glycogen stores in the liver
B. Hypoglycemia and hepatomegaly
C. Ketoacidosis and hyperglycemia
D. Normal blood glucose and elevated muscle glycogen
🟢 B. Hypoglycemia and hepatomegaly
🔴 RATIONALE: Glucose-6-phosphatase is essential for gluconeogenesis and glycogenolysis to release free
glucose into the blood. A deficiency causes severe hypoglycemia and accumulation of glycogen in the liver,
, leading to hepatomegaly (Von Gierke disease).
5. The binding of a hormone to its receptor on the cell surface initiates a cascade of events. In the case of
glucagon, which of the following is the immediate downstream effector that leads to protein kinase A
activation?
A. Phospholipase C
B. Receptor tyrosine kinase
C. Adenylyl cyclase
D. Guanylate cyclase
🟢 C. Adenylyl cyclase
🔴 RATIONALE: Glucagon binds to a G-protein coupled receptor that activates adenylyl cyclase, which converts
ATP to cAMP. cAMP then activates Protein Kinase A (PKA).
6. During fatty acid oxidation, which of the following is a direct product of the beta-oxidation spiral that
enters the citric acid cycle?
A. Acetyl-CoA
B. Malonyl-CoA
C. Fatty acyl-CoA
D. Glycerol-3-phosphate
🟢 A. Acetyl-CoA
🔴 RATIONALE: Beta-oxidation cleaves two-carbon units from a fatty acyl-CoA chain, producing acetyl-CoA.
This acetyl-CoA then enters the citric acid cycle for complete oxidation.
