AP BIOLOGY

Detailed explanation-1: -Phosphofructokinase 1 (PFK1) catalyzes the irreversible conversion of fructose-6-phosphate (F6P) and ATP into fructose-1, 6-bisphosphate (F1, 6BP) and ADP. PFK is a highly regulated enzyme and a key branching point of glycolysis (Ros & Schulze, 2013; Fig. 1.2).

Detailed explanation-2: -The enzyme hexokinase phosphorylates or adds a phosphate group to glucose in a cell’s cytoplasm. In the process, a phosphate group from ATP is transferred to glucose producing glucose 6-phosphate or G6P. One molecule of ATP is consumed during this phase.

Detailed explanation-3: -The third step is the phosphorylation of fructose-6-phosphate, catalyzed by the enzyme phosphofructokinase.

Detailed explanation-4: -Conversely phosphofructokinase is activated by ADP and AMP which serve to indicate that more energy is required. The changes in intracellular ATP and AMP concentrations that occur in anoxia are sufficient to account for the activation of phosphofructokinase and increased rate of glycolysis observed in such conditions.

Detailed explanation-5: -Phosphofructokinase catalyzes the conversion of fructose-6-phosphate to fructose-1, 6-diphosphate and is a key regulatory enzyme of glycolysis.