Question

The insulin glucagon ratio decreased. The enzyme is active at this time?

• A. Glucokinase
• B. Hexokinase
• C. Phosphofructokinase
• D. Glucose 6 phosphatase

Answer 1

The Correct Option is D

The insulin-glucagon ratio is an indicator of the body's metabolic state. A decreased insulin-glucagon ratio suggests a fasting or energy-deprived state, where glucagon predominates over insulin. In such a state, the body prioritizes processes that increase blood glucose levels, primarily through glucose production and release from the liver.

During fasting, enzymes that promote gluconeogenesis (the synthesis of glucose from non-carbohydrate sources) and glycogenolysis (the breakdown of glycogen to glucose) are active. Among the enzyme options provided, Glucose 6-phosphatase is the correct answer because it is a key enzyme in gluconeogenesis and glycogenolysis. It catalyzes the final step of these processes, converting glucose 6-phosphate to free glucose, which can then be released into the bloodstream to raise blood sugar levels.

Other enzymes listed have different roles:

• Glucokinase: Active in the liver during high-glucose states to facilitate glucose uptake and storage, active when insulin is high relative to glucagon.
• Hexokinase: Functions similarly to glucokinase but with higher affinity for glucose, active in tissues regardless of fasting or fed states.
• Phosphofructokinase: A major regulatory step in glycolysis, active when energy is needed for immediate use, not specifically active in the context of a decreased insulin-glucagon ratio.

In summary, when the insulin-glucagon ratio decreases, the enzyme Glucose 6-phosphatase becomes active to aid in increasing blood glucose levels.