Lactic acid that accumulates in a vigorously exercising muscle is mainly
- A. excreted unchanged in the urine
- B. converted back to glucose within the muscle fibre itself
- C. completely oxidised in the muscle within seconds
- D. carried in the blood to the liver and reconverted to glucose
Explanation
Muscle lacks the enzymes to run gluconeogenesis, so lactate diffuses into the blood and the liver rebuilds it into glucose in the Cori cycle, using ATP from oxygen taken in after exercise. That extra oxygen consumption is the oxygen debt, which is why heavy breathing continues after a sprint has finished. Only a very small fraction of lactate is lost in urine or sweat.
Related questions
The end product of glycolysis is
The oxidative decarboxylation of pyruvic acid to acetyl CoA occurs in the
The first reaction of the Krebs cycle is the combination of acetyl CoA with
How many molecules of NADH are produced in one turn of the Krebs cycle?
The final acceptor of electrons in aerobic respiration is