CUET Preparation Today
Roman numbers in the names of restriction enzymes indicate - |
Number of genus of the bacteria Number of species of bacteria Order in which enzymes were isolated from that strain of bacteria Position at which they cut in the DNA sequence |
Order in which enzymes were isolated from that strain of bacteria |
The correct answer is Option (3)- Order in which enzymes were isolated from that strain of bacteria Restriction enzymes belong to a larger class of enzymes called nucleases. These are of two kinds; exonucleases and endonucleases. Exonucleases remove nucleotides from the ends of the DNA whereas, endonucleases make cuts at specific positions within the DNA. 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. The first restriction endonuclease is –Hind II. Restriction enzymes are named using a convention where the first letter of the name comes from the genus name, and the second and third letters come from the species name of the prokaryotic cell from which they were isolated. For example, EcoRI comes from Escherichia coli RY 13. In EcoRI, the letter ‘R’ is derived from the name of strain. Roman numbers following the names indicate the order in which the enzymes were isolated from that strain of bacteria. |
