Under the conditions of oxygen scarcity, pyruvate does not enter the Kreb's cycle in the form of acetyl CoA. Rather pyruvate is reduced into lactate by accepting the electrons from NADH. Reduction of pyruvate and oxidation of NADH form lactate and NAD+. The process is called lactic acid fermentation.
Here, the NAD+ enter the glycolysis to continue the energy production while lactate is a waste product.
D. Lactic acid
D. Lactic acid
Fermentation takes place When a molecule of glucose is broken down into pyruvate molecules. Fermentation is another source of gaining energy from cellular respiration.
During fermentation, electrons from electron transport chain combine with pyruvate molecules, and this reaction further proceeds in the presence of endogenous organic electron receptors. These organic electron receptors form waste products.
Common products synthesized during fermentation are lactic acid, lactose, and hydrogen. Lactic acid is formed when NADH transfers an electron to pyruvate molecule.
Ethanol and CO2 are biproducts
Fermentation may be defined as the breakdown of glucose molecule in the limited supply of oxygen with the help of microorganisms.
Pyruvate molecules and electrons waste product combine together in fermentation to yield lactic acid and two molecules of ATP. The transfer of electron from NADH to pyruvate molecule generates the lactic acid.
Thus, the correct answer is option (D).
Lactic acid fermentation is a type if fermentation that occurs in our body which doesn't require oxygen. In thus process, ATP and glucose is involved and pyruvate is a condensed form of glucose. In this process the lactic acid is also recycled into the pyrvates and is released as a waste product.
In lactic acid fermentation when an electron is added to pyruvate from NADH lactate is made.(see attachment)