BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Each amino acid has the same fundamental structure, which consists of a central carbon atom, also known as the alpha () carbon, bonded to an amino group (NH2), a carboxyl group (COOH), and to a hydrogen atom.

Detailed explanation-2: -Ornithine is not found in naturally occurring proteins but is produced in liver during formation of urea in ornithine cycle. Liver converts ammonia (obtained from deamination of amino acids) into urea through ornithine cycle.

Detailed explanation-3: -Are amino acids a protein? Amino acids themselves are not protein but they are molecules which combine to form proteins. Thus amino acids and proteins are the building blocks of life.

Detailed explanation-4: -All the proteins including the eukaryotic and prokaryotic proteins are made up of 20 amino acids. In nature, there are only 20 amino acids are present which combine together differently to form all the protein. Hence, “all proteins are formed from 20 amino acids” is the correct answer.