We eat starch in plants and then our digestive systems break down the starch into glucose sugar that we can use for our energy needs. Glycogen is stored in the liver and is broken down into glucose molecules when blood sugar levels drop below normal. Proteins have a large variety of functions. Cholesterol is an important component of the cell membrane, and your body uses cholesterol to make steroid hormones. The genetic code within DNA determines what proteins are made by the cell.
Molecules combine in specific ways to form microscopic cells.
The CELL is the basic living structural and functional unit of the organism. The simplest living organisms, such as bacteria and protozoa, consist of only one cell. Together, cells form tissues. Parietal cells produce acid used in digestion. Mucous cells secrete a thick mucus that protects the stomach lining from stomach acid.