What is the primary function of carbohydrates in living organisms?

Carbohydrates play a crucial role in living organisms primarily by providing energy and structural support. They are composed of carbon, hydrogen, and oxygen atoms, and one of their most well-known functions is serving as a major energy source. Simple carbohydrates, like glucose, serve as quick-access energy, while more complex carbohydrates, like starch and glycogen, serve as energy reserves that can be broken down when needed.

Additionally, carbohydrates contribute to structural components in cells. For instance, cellulose, a complex carbohydrate, is a key component of the cell wall in plants, providing rigidity and strength. In other organisms, such as fungi, chitin, another carbohydrate, serves a similar structural role.

While carbohydrates do not directly store genetic information, catalyze biochemical reactions, or transport nutrients across membranes in the same way other biomolecules like nucleic acids, proteins, or lipids do, their energy provision and structural contributions are foundational for growth, metabolism, and overall cellular function.