UNE Biochemistry Final, Final, Final Exam Review
UNE medical biochemistry| 290 Questions| With
Complete Solutions
Course
UNE Biochemistry
Question 1: Enzyme Kinetics
1. Question: A patient presents with symptoms of lactic acidosis, and tests reveal a
deficiency in pyruvate dehydrogenase (PDH) complex activity. Which of the
following is a likely consequence of this enzyme deficiency?
o A) Increased ATP production
o B) Increased levels of acetyl-CoA
o C) Accumulation of pyruvate and lactate
o D) Increased entry of pyruvate into the TCA cycle
Answer: C) Accumulation of pyruvate and lactate
Rationale: The PDH complex is responsible for converting pyruvate into acetyl-CoA,
which enters the TCA cycle. A deficiency in this complex leads to a buildup of
pyruvate, which is then converted into lactate, resulting in lactic acidosis. ATP
production would decrease due to reduced acetyl-CoA availability.
Question 2: Metabolic Pathways
2. Question: During fasting, the liver generates glucose through gluconeogenesis.
Which of the following substrates cannot be used in gluconeogenesis?
o A) Lactate
o B) Glycerol
o C) Alanine
o D) Acetyl-CoA
Answer: D) Acetyl-CoA
Rationale: Acetyl-CoA cannot be converted into glucose via gluconeogenesis
because the conversion of acetyl-CoA to pyruvate is irreversible. Instead, acetyl-CoA
is used to generate ketone bodies during prolonged fasting or can enter the TCA cycle
for energy production.
Question 3: Amino Acid Metabolism
3. Question: Which amino acid is considered glucogenic and can be converted into
glucose in the liver?
, o A) Lysine
o B) Leucine
o C) Alanine
o D) Phenylalanine
Answer: C) Alanine
Rationale: Alanine is a glucogenic amino acid that can be converted into pyruvate,
which then serves as a substrate for gluconeogenesis in the liver. Lysine and leucine
are ketogenic amino acids and cannot be converted into glucose.
Question 4: Electron Transport Chain
4. Question: A mutation in Complex I of the electron transport chain would most likely
result in which of the following?
o A) Reduced ATP production and increased ROS (reactive oxygen species)
production
o B) Increased ATP production
o C) Increased NADH oxidation
o D) Increased oxygen consumption
Answer: A) Reduced ATP production and increased ROS (reactive oxygen
species) production
Rationale: Complex I is the first step in the electron transport chain, where NADH is
oxidized. A mutation here would hinder ATP production as electrons cannot
efficiently pass through the chain, leading to incomplete reduction of oxygen and
increased production of ROS.
Question 5: Lipid Metabolism
5. Question: In diabetic ketoacidosis, the liver produces excess ketone bodies. Which of
the following best describes the mechanism behind this condition?
o A) Increased glucose uptake in peripheral tissues
o B) Decreased lipolysis in adipose tissue
o C) Increased oxidation of fatty acids to acetyl-CoA
o D) Enhanced glycolysis in the liver
Answer: C) Increased oxidation of fatty acids to acetyl-CoA
Rationale: In diabetic ketoacidosis, insulin deficiency leads to increased lipolysis and
mobilization of free fatty acids from adipose tissue. These fatty acids are oxidized in
the liver to acetyl-CoA, which is then converted to ketone bodies due to a lack of
oxaloacetate for the TCA cycle.
,Question 6: DNA Structure and Replication
6. Question: DNA replication is semiconservative. Which of the following best
describes this term?
o A) Each new DNA molecule consists of two old strands
o B) Each new DNA molecule consists of one old strand and one new strand
o C) Each new DNA molecule consists of two new strands
o D) The entire parental DNA molecule is conserved
Answer: B) Each new DNA molecule consists of one old strand and one new
strand
Rationale: In semiconservative replication, each original strand serves as a template
for a new strand, resulting in two DNA molecules, each with one original and one
newly synthesized strand.
Question 7: pH and Buffers
7. Question: In the human body, bicarbonate acts as a major buffer system. What is the
main mechanism by which it maintains pH in the blood?
o A) By binding with hydrogen ions to form carbonic acid
o B) By dissociating into carbon dioxide and water
o C) By increasing the concentration of hydrogen ions
o D) By binding with oxygen to increase blood pH
Answer: A) By binding with hydrogen ions to form carbonic acid
Rationale: Bicarbonate binds with hydrogen ions in the blood to form carbonic acid,
which is then converted to CO₂ and water in the lungs, maintaining blood pH within a
narrow range.
Question 8: Metabolic Disorders
8. Question: A patient with a deficiency in glucose-6-phosphatase would have impaired
ability to perform which of the following processes?
o A) Glycolysis
o B) Gluconeogenesis
o C) Glycogenolysis
o D) Fatty acid oxidation
Answer: B) Gluconeogenesis
Rationale: Glucose-6-phosphatase is necessary for the final step of gluconeogenesis,
converting glucose-6-phosphate to free glucose. A deficiency here impairs glucose
release from the liver, affecting blood glucose regulation, especially during fasting.
, Question 9: Fatty Acid Metabolism
9. Question: Carnitine is essential for which step in fatty acid metabolism?
o A) Beta-oxidation of fatty acids
o B) Transport of fatty acids into the mitochondria
o C) Synthesis of fatty acids
o D) Conversion of fatty acids to triglycerides
Answer: B) Transport of fatty acids into the mitochondria
Rationale: Carnitine helps shuttle long-chain fatty acids across the mitochondrial
membrane, allowing them to enter the mitochondria for beta-oxidation and
subsequent ATP production.
Question 10: Protein Structure
10. Question: In protein structure, the secondary structure is primarily stabilized by
which type of bonds?
o A) Ionic bonds
o B) Disulfide bonds
o C) Hydrogen bonds
o D) Hydrophobic interactions
Answer: C) Hydrogen bonds
Rationale: Secondary structures, such as alpha-helices and beta-sheets, are stabilized
by hydrogen bonds between the backbone amine and carbonyl groups in the
polypeptide chain.
Question 11: Vitamin Deficiencies
11. Question: A deficiency in vitamin B12 can lead to which of the following symptoms?
o A) Night blindness
o B) Microcytic anemia
o C) Neurological symptoms and megaloblastic anemia
o D) Scurvy
Answer: C) Neurological symptoms and megaloblastic anemia
Rationale: Vitamin B12 is essential for DNA synthesis and nerve health. Its
deficiency leads to megaloblastic anemia (due to impaired cell division) and
neurological symptoms due to its role in myelin synthesis.
UNE medical biochemistry| 290 Questions| With
Complete Solutions
Course
UNE Biochemistry
Question 1: Enzyme Kinetics
1. Question: A patient presents with symptoms of lactic acidosis, and tests reveal a
deficiency in pyruvate dehydrogenase (PDH) complex activity. Which of the
following is a likely consequence of this enzyme deficiency?
o A) Increased ATP production
o B) Increased levels of acetyl-CoA
o C) Accumulation of pyruvate and lactate
o D) Increased entry of pyruvate into the TCA cycle
Answer: C) Accumulation of pyruvate and lactate
Rationale: The PDH complex is responsible for converting pyruvate into acetyl-CoA,
which enters the TCA cycle. A deficiency in this complex leads to a buildup of
pyruvate, which is then converted into lactate, resulting in lactic acidosis. ATP
production would decrease due to reduced acetyl-CoA availability.
Question 2: Metabolic Pathways
2. Question: During fasting, the liver generates glucose through gluconeogenesis.
Which of the following substrates cannot be used in gluconeogenesis?
o A) Lactate
o B) Glycerol
o C) Alanine
o D) Acetyl-CoA
Answer: D) Acetyl-CoA
Rationale: Acetyl-CoA cannot be converted into glucose via gluconeogenesis
because the conversion of acetyl-CoA to pyruvate is irreversible. Instead, acetyl-CoA
is used to generate ketone bodies during prolonged fasting or can enter the TCA cycle
for energy production.
Question 3: Amino Acid Metabolism
3. Question: Which amino acid is considered glucogenic and can be converted into
glucose in the liver?
, o A) Lysine
o B) Leucine
o C) Alanine
o D) Phenylalanine
Answer: C) Alanine
Rationale: Alanine is a glucogenic amino acid that can be converted into pyruvate,
which then serves as a substrate for gluconeogenesis in the liver. Lysine and leucine
are ketogenic amino acids and cannot be converted into glucose.
Question 4: Electron Transport Chain
4. Question: A mutation in Complex I of the electron transport chain would most likely
result in which of the following?
o A) Reduced ATP production and increased ROS (reactive oxygen species)
production
o B) Increased ATP production
o C) Increased NADH oxidation
o D) Increased oxygen consumption
Answer: A) Reduced ATP production and increased ROS (reactive oxygen
species) production
Rationale: Complex I is the first step in the electron transport chain, where NADH is
oxidized. A mutation here would hinder ATP production as electrons cannot
efficiently pass through the chain, leading to incomplete reduction of oxygen and
increased production of ROS.
Question 5: Lipid Metabolism
5. Question: In diabetic ketoacidosis, the liver produces excess ketone bodies. Which of
the following best describes the mechanism behind this condition?
o A) Increased glucose uptake in peripheral tissues
o B) Decreased lipolysis in adipose tissue
o C) Increased oxidation of fatty acids to acetyl-CoA
o D) Enhanced glycolysis in the liver
Answer: C) Increased oxidation of fatty acids to acetyl-CoA
Rationale: In diabetic ketoacidosis, insulin deficiency leads to increased lipolysis and
mobilization of free fatty acids from adipose tissue. These fatty acids are oxidized in
the liver to acetyl-CoA, which is then converted to ketone bodies due to a lack of
oxaloacetate for the TCA cycle.
,Question 6: DNA Structure and Replication
6. Question: DNA replication is semiconservative. Which of the following best
describes this term?
o A) Each new DNA molecule consists of two old strands
o B) Each new DNA molecule consists of one old strand and one new strand
o C) Each new DNA molecule consists of two new strands
o D) The entire parental DNA molecule is conserved
Answer: B) Each new DNA molecule consists of one old strand and one new
strand
Rationale: In semiconservative replication, each original strand serves as a template
for a new strand, resulting in two DNA molecules, each with one original and one
newly synthesized strand.
Question 7: pH and Buffers
7. Question: In the human body, bicarbonate acts as a major buffer system. What is the
main mechanism by which it maintains pH in the blood?
o A) By binding with hydrogen ions to form carbonic acid
o B) By dissociating into carbon dioxide and water
o C) By increasing the concentration of hydrogen ions
o D) By binding with oxygen to increase blood pH
Answer: A) By binding with hydrogen ions to form carbonic acid
Rationale: Bicarbonate binds with hydrogen ions in the blood to form carbonic acid,
which is then converted to CO₂ and water in the lungs, maintaining blood pH within a
narrow range.
Question 8: Metabolic Disorders
8. Question: A patient with a deficiency in glucose-6-phosphatase would have impaired
ability to perform which of the following processes?
o A) Glycolysis
o B) Gluconeogenesis
o C) Glycogenolysis
o D) Fatty acid oxidation
Answer: B) Gluconeogenesis
Rationale: Glucose-6-phosphatase is necessary for the final step of gluconeogenesis,
converting glucose-6-phosphate to free glucose. A deficiency here impairs glucose
release from the liver, affecting blood glucose regulation, especially during fasting.
, Question 9: Fatty Acid Metabolism
9. Question: Carnitine is essential for which step in fatty acid metabolism?
o A) Beta-oxidation of fatty acids
o B) Transport of fatty acids into the mitochondria
o C) Synthesis of fatty acids
o D) Conversion of fatty acids to triglycerides
Answer: B) Transport of fatty acids into the mitochondria
Rationale: Carnitine helps shuttle long-chain fatty acids across the mitochondrial
membrane, allowing them to enter the mitochondria for beta-oxidation and
subsequent ATP production.
Question 10: Protein Structure
10. Question: In protein structure, the secondary structure is primarily stabilized by
which type of bonds?
o A) Ionic bonds
o B) Disulfide bonds
o C) Hydrogen bonds
o D) Hydrophobic interactions
Answer: C) Hydrogen bonds
Rationale: Secondary structures, such as alpha-helices and beta-sheets, are stabilized
by hydrogen bonds between the backbone amine and carbonyl groups in the
polypeptide chain.
Question 11: Vitamin Deficiencies
11. Question: A deficiency in vitamin B12 can lead to which of the following symptoms?
o A) Night blindness
o B) Microcytic anemia
o C) Neurological symptoms and megaloblastic anemia
o D) Scurvy
Answer: C) Neurological symptoms and megaloblastic anemia
Rationale: Vitamin B12 is essential for DNA synthesis and nerve health. Its
deficiency leads to megaloblastic anemia (due to impaired cell division) and
neurological symptoms due to its role in myelin synthesis.
