What is the final electron acceptor in the electron transport chain during aerobic respiration?

In aerobic respiration, the final electron acceptor in the electron transport chain is oxygen. As electrons are passed through a series of protein complexes in the mitochondria, they eventually reach oxygen, which combines with these electrons and protons to form water. This process is crucial because it maintains the flow of electrons through the chain and allows for the continued production of ATP, the energy currency of the cell.

Oxygen's role as the final electron acceptor is vital for sustaining cellular respiration in aerobic organisms. Without oxygen, the electron transport chain would come to a halt, leading to a decrease in ATP production and potentially resulting in cell death or dysfunction. The alternatives listed in the other choices—glucose, lactic acid, and carbon dioxide—do not fulfill the role of accepting electrons at the end of the electron transport chain. Instead, glucose is the initial substrate for respiration, lactic acid can be produced in anaerobic conditions, and carbon dioxide is a byproduct of respiration rather than an electron acceptor.