Q177 / 180 · NEET 2020 (Phase 1) · Zoology

Identify the wrong statement with regard to restriction enzymes.

  • A
    They cut the strand of DNA at palindromic sites.
  • B
    They are useful in genetic engineering.
  • Correct answer
    C
    Sticky ends can be joined by using DNA ligases.
  • D
    Each restriction enzyme functions by inspecting the length of a DNA sequence.

Solution

Restriction enzymes cut the strand of DNA a little away from the centre of the palindrome sites, but between the same two bases on the opposite strands. This leaves single–stranded portions at the ends. There are overhanging stretches called sticky ends or cohesive ends on each strand. These are named so because they form hydrogen bonds with their complementary cut counterparts. This stickiness of the ends facilitates the action of the enzyme DNA ligase.

Hence, the correct answer is option: 'C'.

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