Question

which pathway is more active when the energy status of a cell is low? (Explain briefly why)

                        Gluconeogenesis

                        Glycolysis

                        Both Gluconeogenesis and Glycolysis equally active

                        Neither Gluconeogenesis nor Glycolysis will be active

Answer 1

The cellular mechanism is set up in such a way that Gluconeogenesis and Glycolysis does not occur simultaneously. This is so because if they both occurred simultaneously there would be no net production of ATP.

When the energy status of the cell is very low only Glycolysis is active and Gluconeogenesis is inhibited. When the energy level becomes low the allosteric inhibitory pathways that inhibit the glycolysis during the high energy state of the cell is disabled and at the same time the allosteric activation of gluconeogenesis is also disabled. This is because the gluconeogenesis consumes the ATP produced by the glycolysis and a low energy status is given by a low energy charge (ratio of no. of ATP to no. of AMP). So only Glycolysis is active during such situations to increase ATP content. During a relatively high energy state of the cell the glycolysis is inhibited since under those conditions there is no need for extra ATP.