Question

9. The Cori Cycle is advantageous because …

a) The pyruvate, produced during glycolysis, is further oxidized to produce an additional 6 molecules of ATP.

b) It re-synthesizes Phosphocreatine in the liver, from the Creatine produced when PCr is used during ATP synthesis in working muscle.

c) It transforms toxic pyruvic acid to the less toxic molecule, lactate.

d) It transforms toxic lactate to glucose.

Answer 1

Answer should be D) it transforms toxic lactate to glucose.

Cori's cycle operate in between muscle, liver and blood. Lactate produced by muscle is converted first into pyruvate and then into glucose in the liver by gluconeogenesis.

Glucose produced by liver is then transported to the muscle back, which is used as an energy source. This glucose will then be again converted to lactate which will again convert it into another glucose molecule and this cycle continues and produces ATP needed for muscle contraction.

As lactic acid accumulation causes fatigue, it helps in reducing lactate amount by converting it into glucose. Thus, it prevents lactic acidosis in muscle tissues.