Final answer:
F-6-P, or fructose 6-phosphate, is created in gluconeogenesis from fructose-1,6-bisphosphate by the action of fructose-1,6-bisphosphatase, which is an important step in the pathway that contrasts with the glycolysis pathway. Regulatory mechanisms involving fructose 2,6-bisphosphate and hormones such as glucagon and insulin ensure a balance between gluconeogenesis and glycolysis.
Step-by-step explanation:
F-6-P, or fructose 6-phosphate, is made in gluconeogenesis by reversing a step in glycolysis that normally produces fructose-1,6-bisphosphate from F-6-P. To generate F-6-P in gluconeogenesis, the molecule fructose-1,6-bisphosphate is acted upon by the enzyme fructose-1,6-bisphosphatase (FBPase-1), which removes a phosphate group, resulting in the production of F-6-P. This enzyme effectively bypasses the irreversible glycolytic step catalyzed by phosphofructokinase-1 in glycolysis.
The activity of fructose-1,6-bisphosphatase is regulated by fructose 2,6-bisphosphate, which acts as an allosteric inhibitor, thereby controlling the rate of gluconeogenesis. This regulatory mechanism ensures that glycolysis and gluconeogenesis are not active at the same time, allowing the cell to maintain energy balance.
Hormones like glucagon and insulin also play crucial roles in regulating the process of gluconeogenesis. Glucagon stimulates gluconeogenesis, thereby increasing the generation of glucose, especially during fasting or low carbohydrate intake, while insulin inhibits it.