Question

DNA replication happens very fast. In humans, 50 nucleotides are added per second on the new DNA strand. How is this process done with little or no error at such a fast rate?
a.) DNA polymerase seals up the new DNA.

b.) DNA polymerase adds perfect new DNA.

c.) DNA polymerase unwinds the new DNA.

d.) DNA polymerase proofreads new DNA.

Answer 1

Answer:

The correct answer is d DNA  polymerase proofreads the new DNA.

Explanation:

DNA replication proceed with high fidelity.In simple words it means During DNA replication deoxy ribonucleotides are added to the growing DNA strand with little or no error.

  This is because the DNA polymerase 3 contain 3"⇒5" proofreading endonuclease activity which means that enzyme DNA polymerase 3 has the capability to read the newly synthesized DNA strand at 3" to 5" direction to check that all the nucleotides are incorporated correctly in the newly synthesized DNA strand.

 If by mistake any wrong nucleotide is inserted in the newly synthesized daughter DNA strand then DNA replication halts at that point until the wrong base is removed and replaced by a correct base.