Question

9. Imagine that you are sitting on the couch watching TV. After so bored and decide to go to the gym and join the spinning class. Aft come back home and relax while you check your e-mail. Provide a description of how the glycolytic pathway would be regulated as you these activities (home to gym and gym to home). e-moi Pvia burief closs you go through brief 10. Briefly explain how the regulation phosphofructokinase, hexokinase, and pyruvate kinase in the liver differs from how they are regulated in muscle cells.

Answer 1

While you were at home watching tv your activity were limited and you were not wants to have more energy. In this conndition the cells will be producing energy by krebs cycle. On the other hand when the person went to the gym and was started excersising there then the normal aerobic krebs cycle may not be suffiecient for the cells so they produce the energy in anaerobic forms and it is called gycolytic pathway.

Liver has got the complicated mechanism to control the blood glucose level. It has reomove the blood glucose when there is less need for the cells and release the same when there is a need. there are three enzymes that are used to regulate glycolysis in the liver. Phosphofructokinase contains two allosteric inhibitors that were called as  ATP and citrate. When any of these two that is ATP or Citrayte increases in level, tit will produce a negative feed back loop whic in turn prevents the enzyme. Phosphofructokinase in liver cells also contains two allosteric activators, namely AMP and fructose 2,6 bisphosphate. The need for energy drops, the AMP will bind and activate the enzyme. When the glucose level in the blood rises, then also the same process will happen like leading to the production of more fructose 6-phosphate molecules and then transformed to fructose 2,6-bisphosphate, which in turn will activate the phosphofructokinase. Hexokinase is regulated in the same way as in skeletal muscle cells. The difference is only the presence of an isozyme of hexokinase called glucokinase. Glucokinase has a lower affinity for the glucose substrate molecule and is not affected by glucose 6-phosphate inhibition. This implies that under high glucose concentrations, liver cells are very effective in transforming glucose. Finally, pyruvate kinase is also regulated by the same type of allosteric effectors such as ATP, alanine and fructose 1,6 bisphosphate.