Carbohydrates can be simple in their chemical structure like sugar, or complex like cellulose. Cellulose and other similar complex carbohydrates make up the physical structure of plants. Some of these complex carbohydrates cannot be digested by animals, and are then labeled as dietary fiber . Although it is not digested, fiber plays an important role in normal intestinal function in the cat. Proteins Proteins are not one substance, but many substances made up of smaller subunits called amino acids that are linked together.
Proteins also function as hormones and chemical transmitters within nerves.
The sequence and arrangement of the amino acids in a protein determines the function of that protein. Once consumed by an animal, digestion breaks protein down into its constituent amino acids, then they are absorbed into circulation and recombined into structural proteins needed by the animal. Animals can make amino acids on their own, but not all of them. Although there are 23 amino acids, cats require that 11 of them be provided by the diet. Twelve others can be synthesized in the body.