Match List-I with List-II

Choose the correct answer from the options given below:

(A)-(III), (B)-(IV), (C)-(II), (D)-(I)

The correct answer is Option (2) → (A)-(III), (B)-(IV), (C)-(II), (D)-(I)

Detailed Explanation

(A) Nuclease

A nuclease is an enzyme that breaks the phosphodiester bonds that link nucleotides together in a nucleic acid chain (DNA or RNA). There are two main types: exonucleases which remove nucleotides one at a time from the end of a chain, and endonucleases which cleave internal bonds within the chain. This function is essential for processes like DNA repair and replication.

(B) Ligase

A ligase acts like a molecular glue, joining two fragments of DNA together. It catalyzes the formation of a phosphodiester bond between the 3' hydroxyl end of one nucleotide and the 5' phosphate end of another. This is crucial for sealing gaps in the DNA, such as the Okazaki fragments created during DNA replication's lagging strand synthesis.

(C) DNA Polymerase I

DNA Polymerase I is an enzyme found in prokaryotes (like E. coli) that has multiple functions. It synthesizes new DNA in the 5' to 3' direction, but its unique feature is its dual exonuclease activity. It can "proofread" in the 3' to 5' direction to correct mistakes, and it can also remove the RNA primers in the 5' to 3' direction to replace them with DNA during replication.

(D) Reverse Transcriptase

Reverse transcriptase is an enzyme that defies the central dogma of molecular biology by synthesizing a complementary DNA strand from an RNA template. This process is called reverse transcription. This enzyme is famously found in retroviruses like HIV, where it converts the viral RNA genome into a DNA form that can integrate into the host cell's DNA.