What are the final electron acceptor in electron transport chain?

In aerobic respiration, the final electron acceptor in the electron transport chain is oxygen. It accepts two electrons and a molecule of water is formed as a by product.

In anaerobic respiration, the final electron acceptor in the electron transport chain is pyruvate. Anaerobic respiration commonly occurs in the muscle tissue of animals as a result of intense activity or exertion. Pyruvate is used as makeshift electron acceptor in place of oxygen and is reduced or converted to lactic acid.