Question

Two enzymes responsible for restricting the growth of bacteriophages in Escherichia coli were isolated. One was methylase and other was restriction endonuclease. What was the significance of methylase?

• A. able to cut the DNA of bacteriophage at specific sites.
• B. able to remove the methyl group and hence prevent the action of restriction endonuclease on host DNA.
• C. protection of host DNA from the action of restriction endonuclease by adding methyl group to one or two bases usually within the sequence recognized by restriction enzyme.
• D. able to ligate the two cohesive ends of DNA molecule

Answer 1

Answer: (C)

Correct answer is (c) protection of host DNA from the action of restriction endonuclease by adding methyl group to one or two bases usually within the sequence recognized by restriction enzyme.