Because they do.
cells require oxygen to burn sugar.
oxygen
Oxygen
All cells need Oxygen.
Cells use oxygen gas during cellular respiration to generate energy in the form of ATP. Oxygen is essential for the survival of cells because it is necessary for this energy-producing process to occur.
Oxygen is the gas that usually passes into cells. It moves by diffusion from the bloodstream.
Hydrogen gas typically combines with oxygen in fuel cells to produce water, in a process that generates electricity.
All living Cells need Catabolism and Anabolism collectively known as Metabolism
Yes, the cells of the alveoli and lungs require oxygen to carry out cellular respiration. Although the primary function of alveoli is gas exchange, the cells that make up the alveoli and surrounding lung tissue rely on oxygen to produce energy through aerobic respiration. This process is essential for maintaining cellular functions and overall lung health.
oxygen(O2)
Glycolysis can occur without oxygen. Although glycolysis does not require oxygen, it does require NAD+. Cells without oxygen available need to regenerate NAD+ from NADH so that in the absence of oxygen, at least some ATP can be made by glycolysis.
Oxygen is requried for respiration (your cells making 'energy'.)