Question

why does incorporation of di - deoxynucleotides stop dna elongation by dna polymerase iii? di - deoxynucleotides lack a 3-oh, which cannot form a phosphodiester bond with the 5-po4 di - deoxynucleotides lack a 5-oh, which cannot form a phosphodiester bond with the 3-po4 di - deoxynucleotides lack a 3-oh, which cannot form a phosphodiester bond with the 3-po4 di - deoxynucleotides lack a 5-oh, which cannot form a phosphodiester bond with the 5-po4 trick question, as di - deoxynucleotides do not stop dna elongation by dna polymerase iii.

Explanation:

DNA elongation by DNA polymerase III occurs through the formation of phosphodiester bonds between the 3'-OH of the growing DNA strand and the 5'-phosphate ($5'-PO_4$) of an incoming nucleotide. Di - deoxynucleotides lack a 3'-OH group. Without the 3'-OH, a phosphodiester bond cannot be formed with the 5'-PO_4 of the next nucleotide, halting DNA elongation.

Answer:

Di-deoxynucleotides lack a 3'-OH, which cannot form a phosphodiester bond with the 5'-PO₄.