Question

The primary reason leading and lagging strand synthesis is different is because O DNA polymerase only adds new nucleotides to the 3’end of a nucleic acid O DNA polymerase only adds new nucleotides to the 5' end of a nucleic acid O RNA polymerase only adds new nucleotides to the 3' end of a nucleic acid O RNA polymerase only adds new nucleotides to the 5' end of a nucleic acid

Answer 1

Answer :- DNA polymerase only adds new nucleotides to the 3' end of a nucleic acid.

Explanation :-DNA replication is a process where the exact copies of DNA are created . The DNA replication always occur on the basis of a previously synthesized DNA or template DNA

In this process the previously synthesized DNA unzip and each strand act as a template. On the basis of ate two strand is synthesized which are i. Leading strand.

motion of fork 3. TTTTTTTT Replication fork RNA Primer leading strand 3' TTTTTTTTTTTT L okazaki fragments L Lagging Strand fig: Leading and Logging strand Synthesis. so the answer is 'B'

ii. Lagging strand.

i. Leading strand synthesis :- In this process continuous replication occur in 5'-3' direction using 3'-5' strand of parental DNA as a template. This strand is synthesized as one piece adding nucleotides to it's 3' end.

ii. Lagging strand synthesis :- Lagging strand is synthesized on the basis of 5'-3' template DNA in short fragments towards 5'-3' direction. These segments are called Okazaki fragments. Synthesis of each Okazaki fragments begis with RNA primer, synthesis by primase and carried out by DNA polymerase III.

So according to the above discussion it is observed that leading strand of DNA synthesized continuously and lagging strand of DNA synthesized discontinuously and the reason behind that at replication fork both strands are synthesized in 5'-3' direction because DNA polymerase can add new nucleotides only to 3' end , if it able to add nucleotides to 5' end also then both the strands are synthesized in continuous manner.