Read the passage and answer the following question :

In 1963, enzymes that restricted the growth of bacteriophage in Escherichia coli were discovered. Among them, restriction endonucleases played a vital role. Five years later, Hind II, the first restriction endonuclease, was isolated and characterized. Hind II was known for its ability to cut DNA molecules at a specific point by recognizing a unique six-base pair sequence, which was termed the "recognition sequence" for Hind II. Currently, over 900 restriction enzymes have been identified from more than 230 bacterial strains, each recognizing different recognition sequences. For example, EcoRI is derived from Escherichia coli RY 13, where the letter 'R' represents the name of the strain, and the Roman numeral indicates the order of enzyme isolation from that strain. Restriction enzymes belong to a larger class of enzymes that can be divided into two types: exonucleases and endonucleases. Exonucleases remove nucleotides from the ends of DNA, while endonucleases make cuts at specific positions within the DNA. Each restriction endonuclease "inspects" the length of a DNA sequence until it finds its specific recognition sequence. Once located, it binds to the DNA and cuts both strands of the double helix at specific points in their sugar-phosphate backbones. Notably, each restriction endonuclease recognizes a specific palindromic nucleotide sequence in the DNA.

In what year were the two enzymes responsible for restricting the growth of bacteriophage in Escherichia coli isolated?

1963

The correct answer is Option (2) -1963

In the year 1963, the two enzymes responsible for restricting the growth of bacteriophage in Escherichia coli were isolated. One of these added methyl groups to DNA, while the other cut DNA. The later was called restriction endonuclease. The first restriction endonuclease–Hind II, whose functioning depended on a specific DNA nucleotide sequence was isolated and characterised five years later. It was found that Hind II always cut DNA molecules at a particular point by recognising a specific sequence of six base pairs. This specific base sequence is known as the recognition sequence for Hind II. Besides Hind II, today we know more than 900 restriction enzymes that have been isolated from over 230 strains of bacteria each of which recognise different recognition sequences.