Question

DNA repair in prokaryotes is carried out by
A. Ligase.
B. DNA polymerase III.
C. DNA polymerase II.
D. None of the above.

Answer 1

Hint: A DNA polymerase is an enzyme that catalyses the formation of DNA molecules from nucleoside triphosphates, which are the molecular precursors of DNA. These enzymes are required for DNA replication and typically operate in pairs to produce two identical DNA duplexes from a single DNA duplex. One nucleotide at a time, DNA polymerase binds nucleotides to the three primes \[\left( { - 3'} \right)\] ends of a DNA strand. When a cell divides, DNA polymerases are needed to replicate the cell's DNA so that each daughter cell receives a copy of the original DNA molecule.

Complete explanation:
Option A: By joining breaks in the phosphodiester backbone of DNA that occur during replication and recombination, as well as as a result of DNA damage and its repair, DNA ligases play an important role in maintaining genomic integrity.
So, option A is incorrect.
Option B: DNA polymerase I (also known as Pol I) is an enzyme involved in prokaryotic DNA replication. Pol I's main physiological role is to repair DNA damage, but it also connects Okazaki fragments by removing RNA primers and replacing the strand with DNA.
So, option B is incorrect.
Option C: DNA polymerase II is a major enzyme that has \[3' - 5'\] exonuclease activity and polymerizes nucleotide bases, making it essential for DNA repair.
So, option C is correct.
Option D: DNA polymerase II is a crucial enzyme for DNA repair because it has \[3' - 5'\] exonuclease activity and polymerizes nucleotide bases.
So, option D is incorrect.

Hence, Option C is the correct answer.

Note:
DNA repair is a collection of processes that a cell uses to detect and repair damage to the DNA molecules that encode its genome. DNA pol I, DNA pol II, and DNA pol III are the three main types of polymerases found in prokaryotes. DNA pol III is now known to be the enzyme needed for DNA synthesis; DNA pol I is an effective accessory enzyme in DNA replication and is primarily required for repair, along with DNA pol II.DNA Pol II is involved in the replication of DNA. DNA Pol II is the main polymerase for repairing interstrand cross-links, which is an essential function.