A genetic disorder renders fructose 1,6 – biphosphatase in liver less sensitive to regulation by fructose 2,6 – biphosphate. All of the following metabolic changes are observed in this disorder except:
**Core Concept**
The question tests understanding of **fructose metabolism** and **regulation of glycolysis and gluconeogenesis**. Fructose 1,6-bisphosphatase is a key enzyme in gluconeogenesis, while fructose 2,6-bisphosphate is a potent regulator of both glycolysis and gluconeogenesis.
**Why the Correct Answer is Right**
Fructose 1,6-bisphosphatase is normally inhibited by fructose 2,6-bisphosphate, which is a product of phosphofructokinase-2. If fructose 1,6-bisphosphatase becomes less sensitive to fructose 2,6-bisphosphate, gluconeogenesis would be increased, and glycolysis would be decreased. However, the exact answer choice is missing, so we'll proceed with general principles.
**Why Each Wrong Option is Incorrect**
**Option A:** Would be incorrect if it stated an increase in glycolysis, as the disorder would lead to decreased glycolysis.
**Option B:** Might be incorrect if it suggested a decrease in gluconeogenic intermediates, as the disorder would increase gluconeogenesis.
**Option C:** Could be incorrect if it proposed an increase in fructose 2,6-bisphosphate levels, as the enzyme's insensitivity would not directly increase fructose 2,6-bisphosphate.
**Option D:** Without the specific answer choices, we cannot directly address why each is incorrect, but we can infer based on the disorder's effects on metabolism.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that **fructose 2,6-bisphosphate** plays a crucial role in regulating the balance between glycolysis and gluconeogenesis. Disorders affecting its regulation or the enzymes it regulates can lead to significant metabolic imbalances.
**Correct Answer:**