Carbohydrates provide energy to cells, and they act as signaling molecules that communicate with the internal and external environment. The body turns carbohydrates into glucose, which it then uses immediately or stores.
Around 5 percent of the cell membrane features carbohydrates. In addition to providing the cell with structure, they make communication easier. Carbohydrates help to mediate what goes on inside the cell, and they play a role in helping them recognize alien pathogens that enter the body. When a carbohydrate is attached to a lipid, it is called a glycolipid and it aids intracellular signaling. In contrast, glycoproteins identify foreign substances that enter the cell. Cell surface carbohydrates also arrange proteins within the cell, which assists with the cell's functioning.
Without carbohydrates, proteins would not have a steady source of energy. After they enter the body, carbohydrates are broken down into smaller molecules ready for absorption through the cell wall. Insulin assists glucose in moving into the cells, which then aids in adenosine triphosphate production to produce cell energy. Excess glucose is stored in the liver and muscles in the form of glycogen. When the body does not have carbohydrates as a source of energy, it breaks down protein instead. Glycogen is particularly important when someone is exercising, as they need a rapid source of energy.