Question

Using ONLY a clearly labeled diagram show how lactate generated in skeletal muscle can be

converted into glycogen in skeletal muscle.

Answer 1

Lactate produced by active skeletal cell and erythrocyte is the source of energy for other organs. Erythrocyte lack mitochondria and can never oxidize glucose completely.

In contracting skeletal muscle during vigorous exercise, the rate at which glycolysis produces pyruvate exceeds the rate at which citric acid cycle oxidizes it. In these cells, lactate dehydrogenase reduces excess pyruvate to lactate to restore redox balance. However, lactate is dead end in metabolism. It must be converted back into pyruvate before it can be metabolized.

Both pyruvate and lactate diffuse out of the cell through carries into bloodstream. In contracting skeletal muscle, the formation and release of lactate lets the muscle generate ATP in the absence of glucose and shifts the burden of metabolizing lactate from muscle to other organs.

Contracting skeletal muscle supplies lactate to the liver, which uses it to synthesize and release glucose. Thus, the liver restores the level of glucose necessary for active muscle cells, which derives ATP from the glycolytic conversion of glucose into lactate. ( Cori cycle)