Question

What is plasmid? Give its importance.

Answer 1

Hint: Plasmids were discovered by molecular biologist Joshua Lederberg in 1952 .He called them as extra chromosomal hereditary determinants. The most commonly used plasmid in Recombinant DNA Technology is E.Coli plasmid. The advantage of the plasmid is that they are capable of self replicating.

Complete answer:
To solve this question, we must know about the plasmids and its significance.
Plasmids are the extra chromosomal region of circular DNA which is capable of self replicating. The plasmids contain an
1.Origin of replication called the Ori region- It contains AT bases.
2.MCS region or the multiple cloning sites which contains several sites for restriction enzymes.
3.Antibiotic resistant gene makes the plasmid resistant to drugs.

Importance of Plasmid
1.The plasmids are mainly used as vectors in RDT or genetic engineering. The desired genes are inserted in the plasmid. These plasmids are capable of replicating in the host. Thus they find application in making hybrids.
2.It is used to make multiple copies of a certain gene. This finds application in the production of monoclonal antibodies and certain drugs and hormones like insulin.
3.The plasmids are also used for drug delivery and certain therapeutic uses.
4.It is widely used to develop plants which are resistant to antibiotics.

Note: The plasmids are present in all bacterial cells. The bacterial plasmid is transferred by the process of conjugation. pBR322 is the most widely used plasmid. It consists of genes which are resistant to ampicillin and tetracycline. It has more than forty restriction specific sites.