Question

In a normal cell,______ of the errors that occur during DNA replication are ____. A. 10%......repaired by the exonuclease activity of DNA polymerase B. 99%.....repaired by the exonuclease activity of DNA polymerase C. 99%.....repaired by the mismatch repair pathway D. 99%......not repaired prior to mitosis

Answer 1

About 99% of the errors that occur during DNA replication are repaired by the mismatch repair pathway, which helps in recognizing misincorporated bases, excising them, and correcting the sequence to maintain genetic stability.

Step-by-step explanation:

In a normal cell, the correct answer is that 99% of the errors that occur during DNA replication are repaired by the mismatch repair pathway. DNA replication is an incredibly accurate process with DNA polymerase adding nucleotides to the growing DNA strand, and also proofreading each new addition for errors. When errors do slip past the proofreading activity of DNA polymerase, the mismatch repair system corrects most of these errors by recognizing the misincorporated base, excising it, and resynthesizing the correct sequence. This mechanism helps maintain the genetic stability by reducing the occurrence of mutations that can lead to conditions like cancer. In the absence of proper mismatch repair, these errors can persist and lead to more permanent genetic damage.

Answer 2

The correct option is B. In a normal cell, 99% of the errors that occur during DNA replication are repaired by the exonuclease activity of DNA polymerase

Step-by-step explanation:

DNA proofreading can be described as a method by which in which the DNA polymerases check and repair any errors they might have made during the replication of the DNA. The exonuclease activity of the DNA interprets whenever a wrong nucleotide has been placed and corrects it.

Without the method of proofreading, the DNA would undergo many errors during the process of replication which will lead to many faulty proteins being formed.