Food and Energy

Every animal and plant needs food for energy. Plants get food by making it themselves, but humans and animals have to find food.

Food is used in the human body as both energy and building blocks. Large molecules of food that contain mostly oxygen, hydrogen, and carbon are broken down into smaller parts during digestion. These are then re-arranged into molecules used by the cells. This process is called cellular respiration. The molecules important for this process are fats, proteins, and sugars.

The process of cellular respiration starts when food molecules enter cells in the form of glucose. Cellular respiration requires glucose and oxygen. The glucose and oxygen are used by the cytosol and the mitochondria in the cell to create energy. The result of this process is carbon dioxide and water.