How many nucleotides are needed to code for an amino acid

Three nucleotide

Explanation:

Three nucleotides are required to code for one amino acid. There are four types of nucleotides A, T, G, C which make DNA. So a doublet of nucleotide code which involves only two nucleotide would be insufficient to code for 20 amino acids because if 4 different nucleotide is taken two at a time then it can only produce 16 amino acid (4²=16).

But if we take three-nucleotide than the number reaches 64 which is more than sufficient to code for 20 different amino acids (4³ = 64). Therefore 3 nucleotides are needed to code for an amino acid.