Q195 / 200 · NEET 2004 · Zoology

Restriction endonucleases:

  • A
    are present in mammalian cells for degradation of DNA when the cell dies
  • B
    are used in genetic engineering for ligating two DNA molecule
  • C
    are used for in vitro DNA synthesis
  • Correct answer
    D
    are synthesized by bacteria as part of their defense mechanism.

Solution

Restriction enzymes are degradative enzymes which recognizes and cuts up DNA that is foreign to a cell. These enzymes protect bacteria against intruding DNA from other organisms such as virus or other bacterial cells. Related Theory Restriction endonuclease cuts DNA atspecific site, where complementary DNA binds. Multiple restriction enzyme increases the specificity of DNA binding sites, giving more reliable results.

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

Relevant Questions