Cellulose is a type of carbohydrate that can be digested by ruminants and not by humans. Ruminants have a large sac-like structure between small and large intestine. 

In this structure, the food containing cellulose is digested by the action of certain bacteria. On the other hand, due to the absence of cellulose digesting enzymes, humans cannot digest cellulose.

Carbohydrates are a class of organic compounds that consist of carbon, hydrogen, and oxygen atoms. They serve as a major source of energy for living organisms, including ruminants. Ruminants are a group of mammals that possess a specialized digestive system for breaking down plant materials.

The carbohydrate found in ruminants is primarily in the form of cellulose, hemicellulose, and starch. These complex carbohydrates are present in the cell walls of plants and provide the primary energy source for ruminants.

Cellulose:
Cellulose is the most abundant carbohydrate on Earth and constitutes a major component of plant cell walls. It is a linear polymer of glucose molecules, connected by beta-1,4-glycosidic bonds. Ruminants have a unique digestive system that allows them to break down cellulose with the help of microorganisms residing in their rumen. These microorganisms produce enzymes called cellulases that can hydrolyze the beta-1,4-glycosidic bonds, releasing glucose units for energy.

Hemicellulose:
Hemicellulose is another complex carbohydrate found in plant cell walls. It is a heterogeneous polymer consisting of various sugar monomers, such as glucose, xylose, mannose, and galactose. Ruminants can digest hemicellulose through the fermentation process that occurs in their rumen. Microorganisms in the rumen produce enzymes called hemicellulases, which break down the hemicellulose into its constituent sugar units. These sugars are then fermented into volatile fatty acids, which are used as an energy source by the ruminant.

Starch:
Starch is a storage carbohydrate found in various plant parts, such as seeds, tubers, and stems. It is a polymer of glucose molecules, connected by alpha-1,4-glycosidic bonds in amylose and alpha-1,4- and alpha-1,6-glycosidic bonds in amylopectin. Ruminants can digest starch through the action of enzymes produced in their salivary glands, pancreas, and small intestine. These enzymes, such as amylase, break down starch into smaller glucose units, which can be absorbed and used as an energy source by the ruminant.

In conclusion, ruminants rely on cellulose, hemicellulose, and starch as their primary sources of carbohydrates for energy. These complex carbohydrates are broken down through the action of microbial enzymes in the rumen or through the secretion of digestive enzymes in the salivary glands, pancreas, and small intestine. The ability of ruminants to efficiently digest and utilize these carbohydrates is essential for their survival and energy requirements.