A researcher observes that glycolysis is highly active even at low concentrations of fructose 2,6-bisphosphate. What is the likely explanation?

• A. Fructose 2,6-bisphosphate is ineffective at low concentrations.
• B. PFK1 is not regulated by fructose 2,6-bisphosphate.
• C. Fructose 2,6-bisphosphate is a potent activator of PFK1 even at low concentrations.
• D. Glycolysis is independent of fructose 2,6-bisphosphate levels.

Answer: (C)