How Does Starch Function in Living Things?

Starch is a polysaccharide that is essential for storing energy in plants. Humans consume starch and process it into glucose as a vital energy source.

Starch is a form of carbohydrate that contains around 300 to 1,000 combined glucose units, and it's tinier than cellulose units. Carbohydrates supply energy to the cells of living things, and they consist of carbon, hydrogen and oxygen. Humans consume carbohydrates from foods produced through photosynthesis in plants. These carbohydrates are available in the form of starches, sugars or cellulose.

In plants, starch is produced and stored in the photosynthetic cell for future use, and it has an insoluble external layer that stays in the cell. Plants need glucose not only for energy but also for building the cell walls. Starches comprise the cells walls surrounding the photosynthetic cells. Plants eventually break down starch into soluble glucose units that are easier to process than the sturdy starch that binds the glucose.

Some of the food sources that consist of starch granules include rice, wheat, corn and potatoes. Humans have a digestive system that turns starches into glucose with the help of enzymes, which are essential in metabolizing foods. The glucose molecules flow in the bloodstream as a source of energy for the body. Animals have a similar source of energy called glycogen, which is kept in the muscles or liver.