The condensation reaction that forms nucleic acid polymers occurs between a group on one nucleotide and a group on a second nucleotide.

1=hydroxyl of phosphate

2=hydroxyl

Explanation:

Nucleic acid is the condensation polymer of nucleotide. Nucleotides are link together through ester bond. The hydroxyl group of phosphate on one nucleotide goes to condensation reaction with the hydroxyl group of another nucleotide. This is chain process, a large molecule of nucleic acid is formed. It is also called polynucleotide.

RNA and DNA are formed by the nucleic acid. The building block of nucleic acid made up of three chemicals.

Pentose sugar:

The sugars present in DNA and RNA is pentose. In DNA this sugar is deoxyribose while in case of RNA this is ribose sugar. The hydroxyl groups are present on these sugars. Ribose consist of four hydroxyl group while deoxyribose consist of three hyrdroxyl group. These react with phosphoric acid and carboxylic acid and form ester.

Base:

RNA and DNA are consist of four bases:

DNA= Adenine, guanine, thymine, cytosine

RNA= Adenine, guanine, uracil, cytosine

Phosphate:

The inorganic acid H3PO4 is present. The hydroxyl group present on it undergoes the reaction with amines and alcohol to form amide and ester respectively.