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Shortcut used: Identify the tested biochemical principle, track charge/carbon/electrons or pathway direction, use the passage data, and reject choices that contradict cellular location or chemical behavior.
Solve in 3 steps:
- Mark the given values and the exact target.
- Apply the relevant formula, rule, or concept.
- Check the final value against the options.
Common mistake: Do not choose an option before confirming the exact demand of the question.
Question 10
Multiple Choice Question
Question
PASSAGE 4 — FASTING METABOLISM
After a healthy adult fasts overnight, insulin is low and glucagon is elevated. The liver first supports blood glucose through glycogenolysis and increasingly through gluconeogenesis. Adipose tissue releases fatty acids, which the liver oxidizes to generate acetyl-CoA and energy. Some acetyl-CoA is converted to ketone bodies. Red blood cells, which lack mitochondria, continue converting glucose to lactate.
QUESTION 10: Which liver pathway directly creates glucose from lactate during fasting?
Explanation
Correct Answer: B
ANSWER
Correct Answer: B
Method / Topic: Biochemistry
The correct answer is B: Gluconeogenesis. The liver converts lactate to pyruvate and then uses gluconeogenesis to form glucose, which can return to the blood. This liver–muscle or liver–red-cell exchange is the Cori cycle. Glycolysis runs in the opposite direction.
Why this answer is correct
The correct option matches the required rule and the given information.
Short Explanation
The correct answer is B: Gluconeogenesis. The liver converts lactate to pyruvate and then uses gluconeogenesis to form glucose, which can return to the blood. This liver–muscle or liver–red-cell exchange is the Cori cycle. Glycolysis runs in the opposite direction.
Detailed Explanation
Question
PASSAGE 4 — FASTING METABOLISM
After a healthy adult fasts overnight, insulin is low and glucagon is elevated. The liver first supports blood glucose through glycogenolysis and increasingly through gluconeogenesis. Adipose tissue releases fatty acids, which the liver oxidizes to generate acetyl-CoA and energy. Some acetyl-CoA is converted to ketone bodies. Red blood cells, which lack mitochondria, continue converting glucose to lactate.
QUESTION 10: Which liver pathway directly creates glucose from lactate during fasting?
ANSWER
Correct Answer: B
Method / Topic: Biochemistry
The liver converts lactate to pyruvate and then uses gluconeogenesis to form glucose, which can return to the blood. This liver–muscle or liver–red-cell exchange is the Cori cycle. Glycolysis runs in the opposite direction. To solve this kind of MCAT biochemistry
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Question 10
Learn + Solve: Shortcut, Trap & Fast Route Click to view shortcut, steps, and common mistake
Learn + solve
Shortcut used, common trap, and the fastest solving route
Shortcut used: Identify the tested biochemical principle, track charge/carbon/electrons or pathway direction, use the passage data, and reject choices that contradict cellular location or chemical behavior.
Solve in 3 steps:
- Mark the given values and the exact target.
- Apply the relevant formula, rule, or concept.
- Check the final value against the options.
Common mistake: Do not choose an option before confirming the exact demand of the question.
Question
PASSAGE 4 — FASTING METABOLISM After a healthy adult fasts overnight, insulin is low and glucagon is elevated. The liver first supports blood glucose through glycogenolysis and increasingly through gluconeogenesis. Adipose tissue releases fatty acids, which the liver oxidizes to generate acetyl-CoA and energy. Some acetyl-CoA is converted to ketone bodies. Red blood cells, which lack mitochondria, continue converting glucose to lactate. QUESTION 10: Which liver pathway directly creates glucose from lactate during fasting?
Explanation
Correct Answer: B
ANSWER
Correct Answer: B
Method / Topic: Biochemistry
The correct answer is B: Gluconeogenesis. The liver converts lactate to pyruvate and then uses gluconeogenesis to form glucose, which can return to the blood. This liver–muscle or liver–red-cell exchange is the Cori cycle. Glycolysis runs in the opposite direction.
Why this answer is correct
The correct option matches the required rule and the given information.
Short Explanation
The correct answer is B: Gluconeogenesis. The liver converts lactate to pyruvate and then uses gluconeogenesis to form glucose, which can return to the blood. This liver–muscle or liver–red-cell exchange is the Cori cycle. Glycolysis runs in the opposite direction.
Detailed Explanation
Question
PASSAGE 4 — FASTING METABOLISM
After a healthy adult fasts overnight, insulin is low and glucagon is elevated. The liver first supports blood glucose through glycogenolysis and increasingly through gluconeogenesis. Adipose tissue releases fatty acids, which the liver oxidizes to generate acetyl-CoA and energy. Some acetyl-CoA is converted to ketone bodies. Red blood cells, which lack mitochondria, continue converting glucose to lactate.
QUESTION 10: Which liver pathway directly creates glucose from lactate during fasting?
ANSWER
Correct Answer: B
Method / Topic: Biochemistry
The liver converts lactate to pyruvate and then uses gluconeogenesis to form glucose, which can return to the blood. This liver–muscle or liver–red-cell exchange is the Cori cycle. Glycolysis runs in the opposite direction. To solve this kind of MCAT biochemistry
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