Quiz 8: Glycolysis


The pathways for the glucose and fructose metabolism are as follows: img From above, it gets clear that the energy production becomes same in both the pathways. But the positive point of fructose pathway is that the fructose pathway bypasses the rate limiting step of the glucose metabolism that is carried out by phosphofructo kinase.

The pancreatic cells secrete insulin from the beta cells of its Islets of Langerhans. The cells consist of GLUT2 (Glucose transporter 2) sensors inside its cytoplasm. When the insulin comes in contact with the plasma membrane of the cells, the GLUT2 sensors come close to the surface of the plasma membrane. These GLUT2 sensors act as channels for the transportation of glucose inside the cells.

ATP (Adenosine triphosphate) is the energy molecule which is important for many cellular reactions. The ATP molecule is used as well as produced in the glycolysis process. The ATP is used in the first three-four steps of glycolysis in which the step catalyzed by phosphofructo kinase is a rate limiting step. The first three-four steps of glycolysis are as follows: img The steps 1 and 3 of glycolysis require ADP to form ATP while in further reactions ATP is used up. These reactions are catalyzed by kinase enzyme. Thus, if there will be more ATP then the reaction requiring ATP and catalyzed by kinase would not occur. Hence, the ATP molecules can be considered as the regulator of glycolysis.