The cell is the basic unit of living organisms. Cells accomplish all the activities and produce all the components of the body. They carry out metabolism, the sum of all the body’s physical and chemical activities. They provide the energy for metabolic reactions in the form of the chemical adenosine triphosphate (ATP), commonly described as the energy compound of the cell. The main categories of organic compounds contained in cells are:
A.Proteins, which include the enzymes, some hormones, and structural materials.
B.Carbohydrates, which include sugars and starches. The main carbohydrate is the sugar glucose, which circulates in the blood to provide energy for the cells.
C.Lipids, which include fats. Some hormones are derived from lipids, and adipose (fat) tissue is designed to store lipids