Glycolysis | Regulation of PFK-1/Glycolysis Via PFK-2 Activity

The video explains the regulation of glycolysis and gluconeogenesis through the enzyme phosphofructokinase-1 (PFK-1). It highlights the role of fructose 2,6-bisphosphate as an allosteric activator of PFK-1, influenced by the hormones insulin and glucagon. Insulin promotes glycolysis by activating PFK-2, which increases fructose 2,6-bisphosphate levels, while glucagon favors gluconeogenesis by activating fructose bisphosphatase 2, reducing fructose 2,6-bisphosphate levels. The balance between these hormones determines the metabolic pathway preference, ensuring proper blood glucose regulation.

What is the primary function of phosphofructokinase one (PFK1) in glycolysis?

• Converts glucose to glucose-6-phosphate

• Converts ATP to ADP

• Converts pyruvate to lactate

• Converts fructose 6 phosphate to fructose 1,6 bisphosphate

Which molecule is crucial for the activation of PFK1?

• Fructose 2,6 bisphosphate

• Glucose 6 phosphate

• Pyruvate

• Fructose 1,6 bisphosphate

What role does PFK2 play in glycolysis regulation?

• It inhibits the action of glucagon

• It is a glycolytic enzyme that breaks down glucose

• It produces fructose 2,6 bisphosphate, which activates PFK1

• It converts pyruvate to acetyl-CoA

How does insulin affect the bifunctional enzyme containing PFK2?

• It inhibits the enzyme, stopping glycolysis

• It converts the enzyme into a different form

• It phosphorylates the enzyme, activating fructose bisphosphatase 2

• It dephosphorylates the enzyme, activating PFK2

What happens to fructose 2,6 bisphosphate levels when glucagon is predominant?

• They decrease, inhibiting PFK1

• They remain unchanged

• They convert to glucose

• They increase, activating glycolysis

Which enzyme becomes active when glucagon is present?

• Hexokinase

• PFK1

• PFK2

• Fructose bisphosphatase 2

What is the primary effect of glucagon on glucose metabolism?

• Increases insulin release

• Promotes glycolysis

• Inhibits gluconeogenesis

• Promotes gluconeogenesis

How does insulin influence blood sugar levels?

• Decreases blood sugar by promoting glycolysis

• Increases blood sugar by promoting gluconeogenesis

• Increases blood sugar by inhibiting glycolysis

• Has no effect on blood sugar

What is the role of the liver in response to glucagon?

• To break down proteins

• To convert glucose to glycogen

• To produce glucose through gluconeogenesis

• To store excess glucose

Why is it important to maintain blood glucose within a narrow range?

• To maintain muscle mass

• To avoid dehydration

• To ensure proper brain function

• To prevent excessive insulin release