How do we know that carbohydrate, protein and lipids are essential for life?

Answer AND Explanation:

A variety of organic and inorganic compounds serve very important roles in living things. The various organic compounds constitute the structures of the body and regulate the chemical processes going on inside it.

Carbohydrates are essential for life since they are oxidised during respiration to release energy. Glucose is the most common respiratory substrate. They are also building blocks of polysaccharides such as starch and cellulose in plants and glycogen in animals.

Lipids are important because they can be oxidized during respiration to release energy. They provide twice the amount of energy for the same weight of carbohydrates. They also act as insulators, source of metabolic water and are major components of cell membranes.

Proteins are important structural components of the cytoplasm and various supportive tissues in the body, transport substances, make up hormones and are used as a source of energy through respiration.