Question

Name four (4) enzymes that are involved in the replication of the bacterial DNA? For each one, briefly describe what it does. Why is the synthesis of new DNA continuous only on one of the two strands of the double helix?

Answer 1

1st enzyme is DNA helicase. It unbind the helical structure of DNA & uncoil it.

2nd enzyme is DNA dependent DNA polymerase enzyme. It is responsible for formation of new template strand with the help of base pairs in 5'-3' direction of coding strand.

3rd enzyme is DNA topoisomerase.

DNA topoisomerases are enzymes that participate in the overwinding or underwinding of DNA. The winding problem of DNA arises due to the intertwined nature of its double-helical structure.

4th enzyme is DNA ligase. It ligates the discontinues DNA frangments known as Okazaki fragments.

DNA replication is discontinuous because the lagging strand needs to be replicated in the opposite direction of the way the replication fork is proceeding. and DNA polymerase can proceed only 5' to 3'.