• They are oxidise to produce energy e.g. glucose
• They serve as structural materials e.g. cellulose. In plants cell walls, morein in the bacterial cell wall, chitin in the cell wall of fung; and exo- skeleton of arthropods.
• They can be stored in the cell without outering the osmotic potential of the cell e.g. starch.
• Glucose with is the end product of carbohydrate digestion is use to check the osmotic pressure of  blood excess glucose is converted to glycogrn and stored there by controlling blood sugar level
• They help the synthesis of nucleic acid e.g. Ribose Dioxyribose
• Carbohydrates combine with proteins to form glycoprotein which are very important in the plasma membrane
• Chains of carbohydrates on the cell membrane act like Antigens for recognition and protections
• The three carbon sugar glyceraldehydes form an intermediate compound in photosynthesis respiration
• Carbohydrates can be converted into other compounds e.g.: fats and proteins.The fats act as an insulator, in generating heat in the body and the proteins act like building materials or repair won out tissues

They help in the synthesis of co-enzymes e.g.: Ribose is used to synthesize the co-enzymes NAD (Nicotinamide Adenine Dinucleatide) and NANP (Nicotinamide Adenine Dinucleatide