BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Proteins, carbohydrates and lipids are made from three basic molecules: carbon, hydrogen and oxygen. However, all proteins contain an element not found in carbohydrates and lipids is nitrogen.

Detailed explanation-2: -Some carbohydrates contain the elements, nitrogen and sulphur. One of the carbon atoms forms a carbonyl (aldehyde or ketone) group whilst the other carbon atoms exhibit hydroxyl groups.

Detailed explanation-3: -Since both the functional groups are attached to the a-carbon so they are called a-amino acids. So, nitrogen is only present in proteins and not in carbohydrates and lipids.

Detailed explanation-4: -Nitrogen is in all amino acids and nucleotides, and therefore in all proteins and nucleic acids. Nitrogen is also a major component of the chitin that makes up the cell walls of fungi and the exoskeletons of aquatic insects and crustaceans.

Detailed explanation-5: -So, the correct option is ‘Nitrogen’