Q.What is a codon?

Nucleic acids - DNA and RNA - are the cell's information-storage and information-transfer molecules, first isolated from the cell nucleus (hence the name). Both are polymers built from repeating monomer units called nucleotides, each composed of three parts: a nitrogenous base (a purine - adenine or guanine - or a pyrimidine - cytosine, thymine or uracil), a five-carbon pentose sugar (deoxyribose in DNA, ribose in RNA), and a phosphate group. A base joined only to a sugar (without phosphate) is called a nucleoside; adding a phosphate group converts it into a nucleotide. A nitrogenous base is an organic, nitrogen-containing heterocyclic ring, quite different in chemistry and biological role from a simple inorganic base (such as NaOH) that merely releases hydroxide ions in water. Successive nucleotides link through a 3'-5' phosphodiester bond, …