Which codon in the sickle cell DNA is altered: 1st , 2nd or 3rd

Mutation in one exon: 1 amino acid will be replaced by another one; variable consequences depending on the amino acid: most of the time a silent mutation; but the Sickle-cell anemia is due to a mutation at the 6th codon of the β gene (Glu->Val).

Explanation:

i googeld it

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.