Question

Q4). Which of the following accurately accounts for why gluconeogenesis is NOT simply the reverse of glycolysis?

A) Gluconeogenesis is reciprocally and oppositely regulated with glycolysis.

B) Gluconeogenesis is reciprocally and oppositely regulated with glycolysis.

C) Gluconeogenesis makes more ATP than glycolysis, so it is endergonic

D) Three steps of glycolysis are highly exergonic and require different enzymes to reverse.

Answer 1

Gluconeogenesis is not simply the reverse of glycolysis due to the presence of three irreversible steps in glycolysis, which are bypassed by specific enzymes unique to gluconeogenesis, making the process endergonic.

Step-by-step explanation:

Which of the following accurately accounts for why gluconeogenesis is NOT simply the reverse of glycolysis? The correct answer is D) Three steps of glycolysis are highly exergonic and require different enzymes to reverse. This is because gluconeogenesis is not a simple reversal of glycolysis; there are crucial distinctions, especially at three key enzymatic steps where the reactions in glycolysis are irreversible. Although gluconeogenesis follows a similar path as glycolysis, it utilizes different enzymes such as pyruvate carboxylase, phosphoenolpyruvate carboxykinase (PEPCK), fructose-1,6-bisphosphatase, and glucose-6-phosphatase to bypass these irreversible steps. Additionally, gluconeogenesis is an endergonic process, requiring the input of ATP and GTP, contrasting with the exergonic nature of glycolysis, which produces ATP.