Oxygen Gas

Definition

Oxygen gas (O2) is a colorless, odorless gas that makes up about 21% of Earth's atmosphere. It's essential for most forms of life because it's used during the process of cellular respiration to produce ATP, an important molecule that provides energy for many processes in living cells.

Related terms

Hemoglobin:

A protein within red blood cells that binds oxygen molecules for transport throughout the body.

Aerobic Respiration:

A type of cellular respiration that requires oxygen in order to generate energy.

Mitochondria:

An organelle found in large numbers in most cells, where biochemical processes of respiration and energy production occur.