The final electron acceptor in lactic acid fermentation is pyruvate.
The Correct Answer and Explanation is:
Correct Answer:
True
Explanation
Lactic acid fermentation is an anaerobic process in which cells generate energy without using oxygen. This type of fermentation occurs in certain bacteria, such as Lactobacillus species, and in muscle cells of animals under low oxygen conditions, such as during intense exercise. The process begins with glycolysis, a pathway that breaks down glucose into two molecules of pyruvate, producing a net gain of two ATP molecules and two NADH molecules.
In aerobic respiration, pyruvate typically enters the mitochondria where it is fully oxidized in the citric acid cycle, and the high-energy electrons from NADH are transferred to the electron transport chain, where oxygen serves as the final electron acceptor. However, in the absence of oxygen, cells must regenerate NAD⁺ to continue glycolysis, since NAD⁺ is a necessary cofactor for the oxidation of glucose.
During lactic acid fermentation, pyruvate plays a crucial role in regenerating NAD⁺ by acting as the final electron acceptor. The enzyme lactate dehydrogenase catalyzes the reduction of pyruvate to lactic acid (or lactate), during which NADH is oxidized back to NAD⁺. This reaction allows glycolysis to continue and ensures a steady supply of ATP, even when oxygen is not available.
Thus, pyruvate accepts electrons from NADH and is converted into lactate. No additional ATP is generated during this step; all of the ATP comes from glycolysis. Nonetheless, this simple mechanism is vital for short bursts of energy under anaerobic conditions.
In summary, the final electron acceptor in lactic acid fermentation is pyruvate, which ensures the recycling of NAD⁺ and maintains energy production in the absence of oxygen. This makes the statement true.
