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Multiple Choice
During the Cori cycle, what process occurs in the muscle fiber?
A
Glucose is converted to lactate through anaerobic glycolysis.
B
Oxygen is used to convert lactate back to pyruvate.
C
Fatty acids are oxidized to produce ATP.
D
Lactate is converted to glucose via gluconeogenesis.
Verified step by step guidance
1
Understand the Cori cycle: The Cori cycle is a metabolic pathway that connects anaerobic glycolysis in muscle cells with gluconeogenesis in the liver. It helps maintain energy balance during intense physical activity when oxygen is limited.
Focus on the muscle fiber's role: In the muscle, glucose undergoes anaerobic glycolysis due to insufficient oxygen availability. This process converts glucose into pyruvate, which is then reduced to lactate to regenerate NAD⁺ for continued glycolysis.
Clarify anaerobic glycolysis: During anaerobic glycolysis, glucose is broken down into two molecules of pyruvate. Since oxygen is not available, pyruvate is converted into lactate by the enzyme lactate dehydrogenase. This allows glycolysis to continue producing ATP under anaerobic conditions.
Exclude unrelated processes: Oxygen is not used in the muscle fiber during anaerobic glycolysis, so processes like converting lactate back to pyruvate or oxidizing fatty acids do not occur in this context. These processes require oxygen and occur in other tissues or under aerobic conditions.
Connect lactate to the liver: Lactate produced in the muscle is transported to the liver via the bloodstream. In the liver, lactate is converted back into glucose through gluconeogenesis, completing the Cori cycle and allowing glucose to be sent back to the muscle for energy.