1. Energy Source: Carbohydrates are the primary source of energy for cells. They are broken down through cellular respiration, releasing energy in the form of ATP (adenosine triphosphate), which fuels cellular processes.

2. Structural Components: Carbohydrates play structural roles in cells. For example, they are found in cell walls of plants (cellulose) and in the exoskeletons of insects (chitin). They also contribute to the structure of DNA and RNA.