Question

In the diagram of pBR$322$, which identifies components correctly?

• A. ori - original restriction enzyme
• B. amp${}^R$, tet${}^R$ - antibiotic resistance genes
• C. $Hind$ III, $Eco$R I - selectable markers
• D. rop - reduced osmotic pressure

Answer 1

The correct option is B amp${}^R$, tet${}^R$ - antibiotic resistance genes

pBR$322$
pBR$322$ is the most common plasmid vector. It is named after Bolivar and Rodriguez. Features of pBR$322$ Common features of pBR$322$ are as follows:

• Rop - It is a specific base sequence that codes for the rop protein involved in the replication of the plasmid.

Restriction sites - It has multiple restriction sites for different restriction enzymes such as $PvuII,PvuI,BamHI,EcoRI,HindIII,PstI,SalI,ClaI$, etc.

• Selectable markers - It has two selectable markers, one for ampicillin resistance ampR and one for tetracycline resistance tetR. They are useful for differentiating transformants from the non-transformants.
• Ori - It has an ori site or origin of replication site. Any piece of DNA when linked to this sequence can be made to replicate within the host cells.

Pictorial representation of pBR$322$
Pictorial representation of pBR$322$:

Final answer:
c. amp${}^R$, tet${}^R$ - antibiotic resistance genes