Biotechnology- Principles and Processes Question 12

12. Following statements describe the characteristics of the enzyme Restriction Endonuclease. Identify the incorrect statement.

[2019]

(a) The enzyme cuts DNA molecule at identified position within the DNA.

(b) The enzyme binds DNA at specific sites and cuts only one of the two strands.

(c) The enzyme cuts the sugar-phosphate backbone at specific sites on each strand.

(d) The enzyme recognizes a specific palindromic nucleotide sequence in the DNA.

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Answer : b

Hints & Solutions

(b) A restriction enzyme or restriction endonuclease is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites. Restriction enzymes are one class of the broader endonuclease group of enzymes. Each restriction endonuclease functions by inspecting the length of a DNA sequence. Once it finds its specific recognition sequence, it will bind to the DNA and cut each of the two strands of the double helix at specific points in their sugar phosphate backbone. These enzymes predictably cut both strands because the sequences they recognize are palindromic. That is the recognition sequences of identical bases on both DNA strands.