Question

Identify the plasmid from the following;
A. AIU I
B. Hind III
C. EcoRI
D. pBr322

Answer 1

Hint: The cutting of the bacterial DNA segment by the help of restriction endonuclease i. e EcoRI, PVI, PVII. That’s why endonuclease cuts at the specific site of the DNA segment and forms a Plasmid or called cloning vector.

Complete answer:
 To link the alien DNA, the vector needs recognition sites for the commonly used restriction enzymes. The ligation of alien DNA is carried out at a restriction site for each enzyme, Otherwise, a vector will get fragmented. Selection of vectors depends on the size of the desired gene and type of host.

-Plasmids- They are double-stranded, circular and extrachromosomal DNA segments found in bacteria which can replicate independently. Plasmids can be taken out of bacteria and made to combine with desired DNA segments through restriction enzymes and DNA ligase. A plasmid carrying DNA of another organism with it is known as a recombinant plasmid or hybrid plasmid or chimeric plasmid.
eg. pBR322, PUC18(Used for gene transfer in bacteria)
Ti plasmid, Ri plasmid ( used for gene transfer in dicot plant).
From the above examples, pBR322 is shown in the figure.

-Coli cloning vector pBR322 showing restriction sites(Hind III, EcoRI, BamHI, Sal I, Pvu II, Cla I),ori and antibiotic resistance genes (ampR and tetR).Rop codes for the proteins involved in the replication of the plasmid.

Hence, the correct answer is option (D).

Additional information:
-pBR322 ,p -plasmid
-BR- Boliver Rodriguez ( name of the scientists who invented)
-322-it's the strain no. Which is used in the time of extraction of plasmid

Note: It has restriction sites like Hind III, EcoRI
BamH I, Puv II etc. This plasmid acts as a recombinant plasmid. In E.coli for plasmid cloning vectors this pBR322 DNA is used.