Question

Formation of lactic acid from pyruvate requires
(A) Decarboxylation
(B) Reduction
(C) Oxidation
(D) Hydration

Answer 1

Hint: The muscles need the energy for its work and the movement. In the process of glycolysis, the glucose is converted into the pyruvate to store in the muscles. When there is the need for energy for the muscles, these pyruvates convert into lactic acid.

Complete answer:
The pyruvate is converted into the lactic acid in the muscle cells. In these cells, the pyruvate is obtained by the result of the glycolysis or the EMP pathway. This pyruvate accepts the electrons from the NADH which is the electron donor and it is converted into the molecule of the lactic acid. Where after donating the electron, NADH is converted into $NA{D^ + }$ions. These obtained $NA{D^ + }$ions are useful in regenerating the glycolysis pathway to be continued under the anaerobic conditions. In this reaction, the electron is added to the molecule of the pyruvate and hence they are called as the electron acceptor. This process involves the acceptance of the electron and the pyruvate is reduced to the lactic acid; hence the reduction is involved in these steps.

$pyruvate + NADH \to Lactic acid + NA{D^ + }$
Hence formation of the lactic acid from the pyruvate involves the process of reduction.

Hence, the correct answer is Option (B)

Note: This fermentation of lactic acid which is obtained from the pyruvate takes place in the anaerobic conditions. This process yields the effective energy in the short period of time ranging from the $10\,$ seconds to the $2$ minutes for the movement of the muscles.