WGU C785 Final Exam 2026/2027 With All The Correct
Answers
Biochemistry | Key Domains: Biomolecular Structure & Function (Proteins, Carbohydrates, Lipids,
Nucleic Acids), Enzyme Kinetics & Regulation, Major Metabolic Pathways (Glycolysis,
Gluconeogenesis, Citric Acid Cycle, Oxidative Phosphorylation, Fatty Acid Metabolism), DNA
Replication & Repair, Transcription & Translation, Genetic & Metabolic Diseases, and Laboratory
Techniques | Expert-Aligned Structure | Exam-Ready Format
Introduction
This structured WGU C785 (Biochemistry) Final Exam for 2026/2027 provides a comprehensive set
of high-quality exam-style questions with correct answers and rationales. It emphasizes the
application of biochemical principles to human health and disease, the integration of metabolic
pathways, analysis of enzymatic data, and understanding the molecular basis of genetic disorders.
Exam Structure:
• Comprehensive Final Exam: (70 QUESTIONS)
Answer Format
All correct answers must appear in bold and cyan blue, accompanied by concise rationales
explaining the biochemical concept, the effect of a mutation or inhibitor, the interpretation of kinetic
data, the outcome of a metabolic imbalance, and why alternative options are structurally,
functionally, or metabolically incorrect.
1. A mutation replaces a glutamic acid with a valine in the beta-globin chain of hemoglobin.
Which disease is most likely caused by this mutation?
A. Thalassemia
B. Sickle cell anemia
C. Hemophilia A
D. Cystic fibrosis
,B. Sickle cell anemia
Sickle cell anemia results from a point mutation in the β-globin gene (GAG → GTG), substituting valine
for glutamic acid at position 6. This hydrophobic residue causes deoxygenated hemoglobin to
polymerize, distorting red blood cells into a sickle shape. Thalassemia (A) involves reduced globin
synthesis, not a structural mutation. Hemophilia A (C) is a clotting factor deficiency. Cystic fibrosis (D)
stems from a CFTR chloride channel mutation.
2. Which enzyme is allosterically inhibited by ATP and activated by AMP in glycolysis?
A. Hexokinase
B. Phosphofructokinase-1 (PFK-1)
C. Pyruvate kinase
D. Aldolase
B. Phosphofructokinase-1 (PFK-1)
PFK-1 is the key regulatory enzyme of glycolysis. ATP allosterically inhibits it (signaling high energy),
while AMP activates it (signaling low energy). Hexokinase (A) is inhibited by glucose-6-phosphate.
Pyruvate kinase (C) is regulated by fructose-1,6-bisphosphate (feedforward) and phosphorylation.
Aldolase (D) is not a key regulatory point.
3. In oxidative phosphorylation, which complex directly pumps protons into the
intermembrane space using electrons from NADH?
A. Complex I
B. Complex II
C. Complex III
D. Complex IV
A. Complex I
,Complex I (NADH:ubiquinone oxidoreductase) accepts electrons from NADH and transfers them to
ubiquinone, pumping 4 protons across the inner mitochondrial membrane. Complex II (B) accepts
electrons from FADH₂ (via succinate) but does not pump protons. Complexes III and IV (C, D) also pump
protons but receive electrons downstream from ubiquinol.
4. A patient with very high levels of blood lactate and pyruvate has a deficiency in which
enzyme?
A. Pyruvate dehydrogenase
B. Lactate dehydrogenase
C. Glucose-6-phosphatase
D. Fructose-1,6-bisphosphatase
A. Pyruvate dehydrogenase
Pyruvate dehydrogenase (PDH) converts pyruvate to acetyl-CoA for entry into the citric acid cycle.
PDH deficiency causes pyruvate accumulation, which is shunted to lactate via lactate dehydrogenase,
causing lactic acidosis. Lactate dehydrogenase deficiency (B) would reduce lactate formation.
Glucose-6-phosphatase (C) and fructose-1,6-bisphosphatase (D) deficiencies affect gluconeogenesis,
not directly causing lactate buildup.
5. Which of the following best describes the role of tRNA in translation?
A. Carries amino acids to the ribosome and matches them to mRNA codons
B. Synthesizes mRNA from a DNA template
C. Forms the structural core of the ribosome
D. Unwinds the DNA double helix
A. Carries amino acids to the ribosome and matches them to mRNA codons
tRNA (transfer RNA) has an anticodon that base-pairs with the mRNA codon and carries the
corresponding amino acid to the growing polypeptide chain. mRNA synthesis (B) is performed by RNA
polymerase. Ribosomal RNA (rRNA) (C) forms the ribosome’s core. DNA helicase (D) unwinds DNA.
, 6. During fatty acid oxidation, which molecule is produced in each cycle that enters the citric
acid cycle?
A. Acetyl-CoA
B. Malonyl-CoA
C. Oxaloacetate
D. Citrate
A. Acetyl-CoA
Each cycle of β-oxidation shortens a fatty acyl-CoA by two carbons, producing one molecule of
acetyl-CoA, which enters the citric acid cycle. Malonyl-CoA (B) is the building block for fatty acid
synthesis and inhibits carnitine palmitoyltransferase I (CPT-1), blocking fatty acid oxidation.
Oxaloacetate (C) and citrate (D) are citric acid cycle intermediates but not direct products of
β-oxidation.
7. A competitive inhibitor affects enzyme kinetics by:
A. Decreasing Vmax and increasing Km
B. Increasing Vmax and decreasing Km
C. Increasing Km with no change in Vmax
D. Decreasing both Km and Vmax
C. Increasing Km with no change in Vmax
A competitive inhibitor binds to the active site, competing with substrate. This increases the apparent
Km (more substrate needed to reach ½Vmax) but does not alter Vmax, as sufficient substrate can
outcompete the inhibitor. Non-competitive inhibition (A) decreases Vmax with unchanged Km.
8. Which amino acid is most likely to be found in the transmembrane domain of an integral
membrane protein?
Answers
Biochemistry | Key Domains: Biomolecular Structure & Function (Proteins, Carbohydrates, Lipids,
Nucleic Acids), Enzyme Kinetics & Regulation, Major Metabolic Pathways (Glycolysis,
Gluconeogenesis, Citric Acid Cycle, Oxidative Phosphorylation, Fatty Acid Metabolism), DNA
Replication & Repair, Transcription & Translation, Genetic & Metabolic Diseases, and Laboratory
Techniques | Expert-Aligned Structure | Exam-Ready Format
Introduction
This structured WGU C785 (Biochemistry) Final Exam for 2026/2027 provides a comprehensive set
of high-quality exam-style questions with correct answers and rationales. It emphasizes the
application of biochemical principles to human health and disease, the integration of metabolic
pathways, analysis of enzymatic data, and understanding the molecular basis of genetic disorders.
Exam Structure:
• Comprehensive Final Exam: (70 QUESTIONS)
Answer Format
All correct answers must appear in bold and cyan blue, accompanied by concise rationales
explaining the biochemical concept, the effect of a mutation or inhibitor, the interpretation of kinetic
data, the outcome of a metabolic imbalance, and why alternative options are structurally,
functionally, or metabolically incorrect.
1. A mutation replaces a glutamic acid with a valine in the beta-globin chain of hemoglobin.
Which disease is most likely caused by this mutation?
A. Thalassemia
B. Sickle cell anemia
C. Hemophilia A
D. Cystic fibrosis
,B. Sickle cell anemia
Sickle cell anemia results from a point mutation in the β-globin gene (GAG → GTG), substituting valine
for glutamic acid at position 6. This hydrophobic residue causes deoxygenated hemoglobin to
polymerize, distorting red blood cells into a sickle shape. Thalassemia (A) involves reduced globin
synthesis, not a structural mutation. Hemophilia A (C) is a clotting factor deficiency. Cystic fibrosis (D)
stems from a CFTR chloride channel mutation.
2. Which enzyme is allosterically inhibited by ATP and activated by AMP in glycolysis?
A. Hexokinase
B. Phosphofructokinase-1 (PFK-1)
C. Pyruvate kinase
D. Aldolase
B. Phosphofructokinase-1 (PFK-1)
PFK-1 is the key regulatory enzyme of glycolysis. ATP allosterically inhibits it (signaling high energy),
while AMP activates it (signaling low energy). Hexokinase (A) is inhibited by glucose-6-phosphate.
Pyruvate kinase (C) is regulated by fructose-1,6-bisphosphate (feedforward) and phosphorylation.
Aldolase (D) is not a key regulatory point.
3. In oxidative phosphorylation, which complex directly pumps protons into the
intermembrane space using electrons from NADH?
A. Complex I
B. Complex II
C. Complex III
D. Complex IV
A. Complex I
,Complex I (NADH:ubiquinone oxidoreductase) accepts electrons from NADH and transfers them to
ubiquinone, pumping 4 protons across the inner mitochondrial membrane. Complex II (B) accepts
electrons from FADH₂ (via succinate) but does not pump protons. Complexes III and IV (C, D) also pump
protons but receive electrons downstream from ubiquinol.
4. A patient with very high levels of blood lactate and pyruvate has a deficiency in which
enzyme?
A. Pyruvate dehydrogenase
B. Lactate dehydrogenase
C. Glucose-6-phosphatase
D. Fructose-1,6-bisphosphatase
A. Pyruvate dehydrogenase
Pyruvate dehydrogenase (PDH) converts pyruvate to acetyl-CoA for entry into the citric acid cycle.
PDH deficiency causes pyruvate accumulation, which is shunted to lactate via lactate dehydrogenase,
causing lactic acidosis. Lactate dehydrogenase deficiency (B) would reduce lactate formation.
Glucose-6-phosphatase (C) and fructose-1,6-bisphosphatase (D) deficiencies affect gluconeogenesis,
not directly causing lactate buildup.
5. Which of the following best describes the role of tRNA in translation?
A. Carries amino acids to the ribosome and matches them to mRNA codons
B. Synthesizes mRNA from a DNA template
C. Forms the structural core of the ribosome
D. Unwinds the DNA double helix
A. Carries amino acids to the ribosome and matches them to mRNA codons
tRNA (transfer RNA) has an anticodon that base-pairs with the mRNA codon and carries the
corresponding amino acid to the growing polypeptide chain. mRNA synthesis (B) is performed by RNA
polymerase. Ribosomal RNA (rRNA) (C) forms the ribosome’s core. DNA helicase (D) unwinds DNA.
, 6. During fatty acid oxidation, which molecule is produced in each cycle that enters the citric
acid cycle?
A. Acetyl-CoA
B. Malonyl-CoA
C. Oxaloacetate
D. Citrate
A. Acetyl-CoA
Each cycle of β-oxidation shortens a fatty acyl-CoA by two carbons, producing one molecule of
acetyl-CoA, which enters the citric acid cycle. Malonyl-CoA (B) is the building block for fatty acid
synthesis and inhibits carnitine palmitoyltransferase I (CPT-1), blocking fatty acid oxidation.
Oxaloacetate (C) and citrate (D) are citric acid cycle intermediates but not direct products of
β-oxidation.
7. A competitive inhibitor affects enzyme kinetics by:
A. Decreasing Vmax and increasing Km
B. Increasing Vmax and decreasing Km
C. Increasing Km with no change in Vmax
D. Decreasing both Km and Vmax
C. Increasing Km with no change in Vmax
A competitive inhibitor binds to the active site, competing with substrate. This increases the apparent
Km (more substrate needed to reach ½Vmax) but does not alter Vmax, as sufficient substrate can
outcompete the inhibitor. Non-competitive inhibition (A) decreases Vmax with unchanged Km.
8. Which amino acid is most likely to be found in the transmembrane domain of an integral
membrane protein?
