Biotechnology - Recombinant DNA - Discussion

What is a restriction endonuclease?

It is an enzyme that breaks the DNA into small pieces.

Bacteriophages are the viruses that attacks the bacteria. During infection phage insert its its DNA into bacteria, which is harmful to bacteria.

Endonuleases by the bacteria as a defense against the bacteriophage. These enzymes degrade the invading phage DNA.

Bacteriophages meaning of bacteria eating.

Restriction endonucleases are those enzymes which cut DNA from palindromic sequences by making sticky ends so that two genes combine easily.

The RE is basically a defense mechanism of bacteria which prevents the bacteria from foreign DNA molecule by decreasing it and his own DNA prevented by RE through methylation of its own DNA.

No, the Correct option is A. Restriction endonucleases are one type of enzymes that cut DNA at their respective sequences. They are used to generate DNA cut to do DNA recombination. And some times to degrade certain pathigenic bacterial DNA, plasmids or phages.

Option A) violates the significance of replication. Broken pieces of DNA ceases replication process if not ligated quickly.

Option C) also incorrect because RNA primers are synthesized by primase and not by res. Endonucleases and so it is obvious that option D) can also be ruled out.

Option B) is correct because the biological role of these enzymes is in restriction-modification (R-M) systems that have evolved to cleave the bacteriophage DNA injected into the cell and thus act as a defence mechanism against phage infection.

Restriction enzymes perform tow activities: restriction digestion and methylation. The important work of restriction enzyme in bacteria is the digestion of foreign DNA and methylation of self DNA for discrimination of foreign and self DNA.