Question

The cycle of reactions by which muscle lactic acid is transformed to muscle glycogen is known as
A. Glycolactic cycle
B. Glycolysis
C. Cori cycle
D. Krebs cycle

Answer 1

Hint: Lactic acid is synthesized in the muscles. During intense exercise, it builds up. It leads to sore and painful muscles. The buildup of lactic acid due to exercise is temporary and hence, it is not a matter of concern. For intense exercise, muscle glycogen is significant fuel. The synthesis of glycogen (polysaccharide of glucose) is a relatively slow process and needs special considerations when there is a lesser time between intense training sessions.

Complete answer
Option C Cori cycle: The Cori cycle is also known as the lactic acid cycle or glucose-lactate cycle, is a metabolic pathway, where lactate synthesized by anaerobic glycolysis in the muscles passes into the liver and is converted into glucose. Then, it returns into the muscles and then, metabolized back into lactate.

So, Option C is correct

                                Fig: Cori Cycle

Additional Information

Option A Glycolactic cycle: Glycolactic cycle converts one molecule of six-carbon glucose into two molecules of three carbon pyruvate with the production of two ATPs. This is unrelated to lactic acid.

Option A is not correct

Option B Glycolysis: In glycolysis, one molecule of glucose is converted into two molecules of pyruvate, two molecules of water, and two hydrogen ions. High energy intermediate molecules such as NADH and ATP are synthesized via this process. So, this is not related to lactic acid.

Hence, Option B is not correct

Option D Krebs cycle: Krebs cycle is also called the tricarboxylic acid cycle. It is a sequence of reactions, which occur in the living organism, where oxidation of acetic acid offers energy for storage in phosphate bonds like in ATP. Its other name is the citric acid cycle.
Option D is not correct

Therefore Option C is the correct answer

Note:
Cori cycle is significant in the prevention of lactic acidosis in the muscles, which occurs during anaerobic conditions. It is capable of producing ATP, which is the source of energy during the activity of muscles. Compared to food, it is the most important source for gluconeogenesis. The pathway has been named after its discoverers, Carl Ferdinand Cori and Gerty Cori.