DNA polymerases add new nucleotides in what direction?
A) 5′ to 3′
B) 3′ to 5′
C) both directions

Question

Quizplus · Accepted Answer

DNA polymerases add new nucleotides in the 5' to 3' direction, which means they add nucleotides to the 3' end of the growing strand. This occurs because DNA polymerases can only read the template strand in the 3' to 5' direction, known as the anti-sense or non-coding strand, and they synthesize the new strand in the complementary 5' to 3' direction, known as the sense or coding strand. The correct base pairing occurs when a new nucleotide is added to the 3' end of the previous nucleotide, forming a 3'-OH group for the next nucleotide to be added via a phosphodiester bond. Therefore, the answer is A) 5' to 3'.

DNA Polymerases Add New Nucleotides in What Direction