Question

EXERCISE 4: Muscle pH 28. If you recall, there are three different metabolic pathways driving ATP production in skeletal muscle that are active at all times. However, the predominant pathway at any given time depends on the speed of the pathway and energy demand of the muscle. a. Which metabolic pathway predominates once creatine phosphate is depleted and before oxidative phosphorylation can occur ? Where does this occur within the cell? b. What is pyruvate converted to when oxygen delivery to a muscle is diminished or insufficient? Pyruvic acid and then to lactic acid i. Would this be more likely to happen in slow-oxidative or fast-glycolytic fibers? c. What will buildup of the product from part b do to the intracellular pH of a muscle fiber? d. What two enzymes directly impact the relaxation and contraction of a muscle fiber? e. How does the above change in the intracellular pH of a muscle fiber affect those enzymes ability to do work?

Answer 1

b.

When oxygen delivery to a muscle is diminished or insufficient, which is generally during intensified athletic exercise, the energy gets liberated via anaerobic assimilation. The pyruvate is converted to lactate, in the presence of lactate dehydrogenase. This is called as the lactic acid fermentation.