Question

How would you explain the role of oxygen in aerobic respiration?

Answer 1

Hint: Oxygen is the terminal acceptor of an electron in the series outside the cell. It then reacts with a proton to form water.

Complete answer:
Oxygen is an important component of cellular respiration. Aerobic respiration is the process by which organisms use oxygen to break down the molecules such as fats and carbohydrates into chemical energy. The metabolism of the glucose during the aerobic respiration takes place in three stages:

1. Glycolysis: in this, the glucose is oxidized and degraded into the pyruvate and produces some ATP and NADH.

2. Krebs’s Cycle: During this process, the pyruvate is degraded and oxidized into carbon dioxide and produces ATP, NADH, and $FADH_2$.

3. Electron transport chain: Electrons are donated from molecules like NADH and $FADH_2$ which are then transferred in the series of coenzymes and cytochrome. The movement of electrons pumps protons from the matrix into the intermembrane space of the mitochondria this creates a concentration gradient. The protons can pass down their concentration gradient back into the matrix via ATP Synthase, and this supplies energy to form ATP.

Oxygen accepts electrons from the final carrier protein and then reacts with a proton to form a water molecule. In the absence of oxygen ceases to function as the protons will not be pumped and ATP Synthase cannot function resulting in the reduced ATP synthesis.

Note: Aerobic metabolism depends upon a circulatory system that transports the oxygen to the different organs where the oxygen then metabolizes the carbohydrates, fats into simpler products.