Chemical processes continually happen inside cells, processes which modify various components and substances (lipids, proteins, carbohydrates, etc.) which act as food for cells, supplying energy to make our body work.
Food enters the cell through the cell membrane. Once inside, it must be processed, which, with the help of enzymes to hurry things along, is the responsibility of mitochondrion.
Generating actions of energy within the cell are collectively know as respiration (sometimes called internal respiration to distinguish it form respiration of the lings) and is completed in two stages. First of all, the food is partially distributed in intermediate substances like alcohol and acids. In this stage, oxygen is not necessary and so it is called anaerobic respiration. The second stage, called aerobic respiration, only produces oxygen if it is available. The intermediate substances then decompose and turn into waste products, like carbon dioxide and water, and release the energy necessary for life.
Energy generated by respiration is not immediately available for the cellular processes. It is temporarily stored in an intermediate known as ATP (adenosine triphosphate, obtained in the mitochondrion), which deposits and provides energy to the cells.
Proteins and Enzymes
The first are considered the chemical bases of life, since key substances (like hormones) are made up of them. Proteins are created inside the cells and are joined chains of hundreds of molecules of more than 20 types of amino acids.
Enzymes catalyze specific biochemical reactions, among them, the combustion of glucose. Without enzymes, many reactions of our body would be so slow that a person could die.
