Question

Part A Researchers found E. coli that had mutation rates 100 times higher than normal. Which of the following is the most likely cause of these results? Researchers found E. coli that had mutation rates 100 times higher than normal. Which of the following is the most likely cause of these results?
a. The proofreading mechanism of DNA polymerase was not working properly.
b. The single-stranded binding proteins were malfunctioning.
c. The DNA polymerase was unable to add bases to the 3' end of the growing nucleic acid chain.
d. There were one or more mismatches in the RNA primer.

Answer 1

Answer:

The correct answer is a the proofreading mechanism of DNA polymerase was not working properly.

Explanation:

Proofreading mechanism is very much important to minimize the mutation rate in a newly synthesized DNA molecule during the course of DNA replication.

  The proofreading activity is mediated DNA polymerase 3 which reads the daughter DNA strands in 3" → 5" direction by exonuclease activity.If any incorrect base is found within the daughter DNA molecule then proofreading activity of DNA polymerase 3 help to excise that incorrect base and replace it with correct base .

   Thus proof reading helps to minimize the mutation rate in the newly synthesized DNA molecule.