Explain the role(s) of the following Biotechnology:
a) Restriction endonuclease
Gel-electrophoresis
c) Selectable markers in pBR322.

Explanation

a) The cutting of DNA at specific locations became possible with the discovery of the so-called molecular scissors-restriction enzymes. The cut place of DNA was then linked with the plasmid DNA.
b) The cutting of DNA by restrictions endonucleases results in the fragments of DNA. These fragments can be separated by a technique known as gel electrophoresis.
c) In addition to 'ori' the vector requires a selectable marker, which helps in identifying and eliminating non-transformants and selectively permitting the growth of the transformants.
Transformation is a procedure through which, a piece of DNA is introduced in a host bacterium. Normally, the genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, tetracycline or kanamycis, etc. are considered useful selectable markers of E.coli. The normal E.coli cells do not carry resistance against any of these antibiotics.