How does cellular respiration happen in animal cells?

Animal cells like all cells, need oxygen to carry out cellular respiration. Blood cells in capillaries get the oxygen from the air in the alveoli and nutrients from the small intestine. The capillaries get in contact with the other cells so the oxygen and nutrients diffuse out of blood cells and into other cells.

Oxygen and sugar enters the cell's mitochondria, and it breaks down the sugar, while the oxygen is releasing energy in the sugar. The energy is stored in the ATP. Like plant cells, animal cells use ATP to carry out cellular respiration.

The reaction between sugar and oxygen produces carbon dioxide and water. The capillaries take the cells with lots of carbon dioxide back to the lungs where they could be oxygenated.