Question

Bacterial DNA protects its own DNA from being cut up by the restriction enzymes present in the cell because _____________ .

A. bacterial DNA has no recongition sequences
B. some of the nucleotides have caps of methyl group
C. recognition sequences are covered with proteins
D. only foriegn DNA can activate the restriction enzymes

Answer 1

Bacterial DNA is protected from its own restriction enzymes by methyl groups added to nucleotides, preventing the enzymes from recognizing and cleaving the host DNA.option is correct.

Step-by-step explanation:

Bacterial DNA protects its own DNA from being cut up by the restriction enzymes present in the cell because some of the nucleotides have caps of methyl groups. These enzymes, called restriction endonucleases, evolved in bacteria as a protection mechanism against invading phages. The methyl groups modify the nucleotides at specific sequences, which are often palindromic, and prevent the restriction enzymes from recognizing and cleaving the host DNA.

As these methylated bases are not recognized by the enzymes, it ensures that the cell's own DNA is protected, while foreign DNA without these modifications is recognized and cleaved. This process of protecting the bacterial DNA while cleaving foreign DNA is known as the restriction modification system.Bacterial DNA is protected from its own restriction enzymes by methyl groups added to nucleotides, preventing the enzymes from recognizing and cleaving the host DNA.