試題詳解

16.Bacterial cells protect their own DNA from restriction enzymes (endonucleases) by_______.  
(A) using DNA ligase to seal the bacterial DNA into a closed circle.
(B) adding methyI groups to adenines and cytosines.
(C) adding histones to protect the double-stranded DNA.
(D) forming "sticky ends" of bacterial DNA to prevent the enzyme (endonuclease) from attaching.
(E) inhibiting enzyme activity.