Question

1. Mark each statement below TRUEor FALSEand give reasons. You will get credit ONLYif your reasoning is correct.

1. Gluconeogenesis is upregulated during prolonged exercise since blood sugar levels drop
2. A substrate cycle between DHAP and GA3-P might be used by some organisms to generate heat
3. A mutation in Adenylate Cyclase would most likely decrease the rate of Gluconeogenesis in liver

Answer 1

a) true

During exercise body uses glucose. This glucose is provided by glycogen stores. During intense exercise glycogen stores become exhausted. Then body gets glucose by the process of gluconeogenesis.

It is a process by which glucose is made from non carbohydrate sources eg amino acids, fats etc.

Hence during exercise gluconeogenesis is upregulated.

2) true

Substrate cycle occurs when two reactions run in opposite reactions and no overall product is formed. It is a futile cycle as no net product is formed and only heat is produced.

DHAP GA-3-P.

It might be used as a substrate cycle for generation of heat by animals.

3) true

Glucagon activates gluconeogenesis in the body by

Glucagon acts through G- coupled receptor →activates adenylate cyclase→ adenylate cyclase converts ATP → cAMP → activates protein kinase A → activates fructose-2,6- bisphosphatase→ inhibits glycolysis → gluconeogenesis takes place.

if there is mutation in adenylate cyclase then it will hinder the above pathway and thus gluconeogenesis in liver.