Explain the importance of carbohydrates and lipids in the human body. Include a discussion of at least two functions of carbohydrates and the roles of two groups of lipids.

Carbohydrates are a group of molecules made out of carbon, hydrogen and oxygen. There are different types of carbs, such as the monosaccharides, the disaccharides and the polysaccharides. The most important metabolic substrate is glucose which is a monosaccharide and it is needed for respiration to produce energy. Lactose is a disaccharide, made of galactose and glucose and it is the carbohydrate for young mammals. Glycogen is a polysaccharide which is made of many glucose molecules, and it is an energy store.

Lipids are anither group of molecules which is made of the same elements as the carbohydrates but at differeent proportions. In the human body there are different types of lipids which have numerous functions like insulation, energy storing, production of certain hormones etc. Cholesterol is a lipid molecule which is responsible for maintaing the fluidity of the cell membrane. A phospholipid is a component of the cell membrane as it makes up the bilayer.