How Does a Bacterial Cell Protect Its Own DNA from Restriction

Question

How does a bacterial cell protect its own DNA from restriction enzymes?
A) by adding methyl groups to adenines and cytosines
B) by using DNA ligase to seal the bacterial DNA into a closed circle
C) by adding histones to protect the double-stranded DNA
D) by forming "sticky ends" of bacterial DNA to prevent the enzyme from attaching
E) by reinforcing the bacterial DNA structure with covalent phosphodiester bonds

Accepted Answer

Bacterial cells use restriction-modification systems to modify their DNA to protect themselves from restriction enzymes. In the modification step, methyl groups are added to specific nucleotide bases (usually adenine or cytosine) in the recognition sequence of the restriction enzyme, marking them as "self" and protecting them from being cut. Therefore, choice A is the correct answer.