Question

4. Describe the different processes that provide ATP within the muscles for intense exercise of short duration and for endurance exercise.

Please give a detailed answer. Add supportive equation if possible.

Answer 1

Three energy systems function to provide ATP in the muscles they are: 1. mitochondrial respiration 2.glycolytic cycle and 3. phospagen

Phoshpagen system :

There are three reactions that comprise the phosphagen system, The creatine kinase and adenylate kinase reactions both produce ATP, yet the creatine kinase reaction has by far the greater capacity for ATP regeneration as the store of CrP in muscle at rest is approximately 26 mmol/kg wet wt.

The other important feature of the phosphagen system, and in particular the adenylate kinase reaction, is the production of AMP. AMP is a potent allosteric activator of two enzymes influential to glycolysis. First, AMP activates phosphorylase, which increases glycogenolysis and therefore the rate of glucose-6-phosphate (G6P) production, which in turn provides immediate fuel for glycolysis. Second, AMP activates phosphofructokinase (PFK) within phase 1 of glycolysis, thereby allowing increased flux of G6P through glycolysis, which in turn allows for increased rates of ATP regeneration

Mitochondrial respiration : The resynthesis of ATP by mitochondrial respiration occurs in mitochondria and involves the combustion of fuel in the presence of sufficient oxygen. The fuel can be obtained from sources within the muscle (free fatty acids and glycogen), and outside the muscle (blood free fatty acids [from adipose tissue], and blood glucose

Carbohydrates oxidation

Lipid oxidation

Amino acid oxidation

Glycolysis :  

glycolysis remains a very rapid means to regenerate ATP compared with mitochondrial respiration [22]. It is convenient to separate glycolysis into two phases. Phase 1 involves six carbon phosphorylated carbohydrate intermediates called hexose phosphates. Phase 1 is also ATP costly, with ATP providing the terminal phosphate in each of the hexokinase and phosphofrucktokinase reactions. Phase 1 is best interpreted to prepare for phase 2, where ATP regeneration occurs at a higher capacity than the cost of phase 1, resulting in net glycolytic ATP yield