What is the primary role of carbohydrates in living organisms?

The primary role of carbohydrates in living organisms is to serve as a source of energy. Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen, and they are essential for various biological functions. They can be broken down through cellular respiration to release energy, which is crucial for the survival and functioning of cells.

Monosaccharides, such as glucose, are simple carbohydrates that provide immediate energy. When multiple monosaccharides link together, they form disaccharides and polysaccharides, such as sucrose and starch, respectively. These polysaccharides not only serve as energy storage molecules but also play a role in providing structural support and facilitating cellular processes. Therefore, carbohydrates are vital not just as energy sources but also in maintaining overall cellular health and function.

The other options represent functions that are associated with different biomolecules. Proteins are the building blocks for various cellular structures and functions, cellular membranes primarily consist of lipids and proteins, and information carriers in cells are largely nucleic acids, like DNA and RNA. Thus, the unique role of carbohydrates is best represented as providing energy.