Question

Oxygen is an essential requirement for aerobic respiration but it enters the respiratory process at the end? Discuss.

Answer 1

Aerobic respiration requires oxygen in order to generate AIR Oxygen is WenglY electronegative element and acts as final acceptor in respiratory process.
It pulls $e^{-}$ (electrons) that energy from the electron transport chain ETC and take up protons from medium to form water.
$O_2$, enters in the respiratory process at the end, though irs presence is vital. It drives the process of aerobic respiration by removing hydrogen from the system. Thus, acting as final hydrogen acceptor.

The energy is produced by the process of oxidative phosphorytation, utilising the energy of exidation reduction reactions.