Question

In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation? Group of answer choices

a.The DNA will supercoil.
b.No proofreading will occur.
c.Replication will require a DNA template from another source.
d.No replication fork will be formed.
e.Replication will occur via RNA polymerase alone.

Answer 1

The correct answer is d. No replication fork will be formed.

Step-by-step explanation:

The function of helicase is to open the DNA duplex at the replication fork so that a single-stranded DNA strand can be provided to the DNA polymerase to start the replication.

In bacteria, dnaB is the primary DNA helicase that binds to the bacteria double-stranded DNA and opens it in 5' to 3' direction.

So if any mutation occurs in dnaB that alters the helicase activity of the enzyme then it will not able to open the DNA at replication fork so no replication fork will be formed and DNA replication will not start. Therefore the right answer is d.