Phosphofructokinase catalyzes the phosphorylation of fructose 6‑phosphate to fructose 1,6‑bisphosphate in glycolysis. Fructose 1,6‑bisphosphatase catalyzes the hydrolysis of fructose 1,6‑bisphosphate to fructose 6‑phosphate in gluconeogenesis. How does fructose 2,6‑bisphosphate (F26BP) affect the activity of the enzymes phosphofructokinase‑1 (PFK) and fructose 1,6‑bisphosphatase (FBPase)?

Fructose 2,6‑bisphosphate (F26BP) activates phosphofructokinase‑1 (PFK -1) and inhibits fructose 1,6‑bisphosphatase (FBPase)

Explanation:

Fructose 2,6‑bisphosphate (F26BP) is a metabolite that is produced with an increase in glucose, hence increasing the availability of fructose-6-phosphate. With, the increased concentration of F26BP, it increases the affinity of PFK- 1 to fructose-6-phosphate, thereby activating glycolysis which enhances the catabolism of glucose. In contrast, F26BP inhibits the activity of  fructose 1,6‑bisphosphatase (FBPase), hence inhibiting gluconeogenesis. Gluconeogenesis (formation of glucose) will not be need since there is the presence of glucose in the system.

In summary, fructose 2,6‑bisphosphate (F26BP) reciprocally controls the enzymatic activity of  phosphofructokinase‑1 (PFK -1) and fructose 1,6‑bisphosphatase (FBPase); it inhibits gluconeogenesis by inhibiting the enzyme, FBPase and activates glycolysis by activating the enzyme PFk -1

"d.) carbon dioxide and hydrogen sulfide"