What is the molecule responsible for making sure that the DNA doesn’t supercoil during replication?

Question

Please choose the answer from the following choices below:

A. Ligase

B. Gyrase

C. Helicase

D. Primase

Note: Please provide an explanation if you can.

Answer 1

DNA gyrase, an example of a bacterial topoisomerase, alleviates supercoiling in DNA. The supercoils build up downstream of the replication fork as a result of helicase activity. Of course, helicase unzips the DNA strands, forming the replication fork in the first place. Primase adds RNA primers to both the leading and lagging strands so that DNA polymerase has a free 3' -OH to actually build new DNA strands. Primase is most active on the lagging strand because of the multiple Okazaki fragments. Finally, DNA ligase seals gaps in the phosphodiester backbone in a DNA strand. These gaps are formed when DNA Pol I (bacterial notation) removes a primer and replaces the primer with new DNA. DNA ligase is most active on the lagging strand.

Answer 2

Gyrase relives DNA supercoiling. Helicase only unwinds DNA and that increases supercoiling. Ligase attaches two broken strands of DNA. Primase is an enzyme that synthesizes short RNA sequences called primers for initiating replication.