Describe briefly the energy conversion processes.

The transformation of energy takes place in several stages. It all starts with preparing food. It is processed by digestive enzymes and broken down into proteins, lipids, carbohydrates, and vitamins. Further, under the action of other enzymes, these substances are split into smaller units. For example – proteins are broken down to amino acids. The main source of energy for living organisms is glucose. It is oxidized in the mitochondria, and when these substances break down into water and carbon dioxide, energy is released.