What is the function of carbohydrates in living organisms?

Carbohydrates play a crucial role in living organisms primarily by providing energy and structural support. They are organic compounds made up of carbon, hydrogen, and oxygen, and are a key source of energy for cells. When consumed, carbohydrates are broken down into glucose, which is then used in cellular respiration to produce ATP—the energy currency of metabolism.

In addition to their role in energy provision, carbohydrates also contribute to the structural integrity of various biological structures. For example, in plants, cellulose—a type of carbohydrate—forms the cell wall, providing rigidity and strength. In animals, certain carbohydrates contribute to the structure of cells and tissues, such as glycoproteins and glycolipids, which are involved in cell recognition and signaling.

The other options misrepresent the functions of their respective components. Cell membranes are primarily made up of phospholipids and proteins rather than carbohydrates. Genetic information is stored in nucleic acids (DNA and RNA), not carbohydrates. Oxygen transport is mainly carried out by hemoglobin in red blood cells, which is a protein, rather than being associated with carbohydrates. Thus, the primary functions of carbohydrates in energy provision and structural support clearly define why they are essential to living organisms.