Explain giving reaons why an alien piece of DNA needs to be integrated to a specific sequence of host DNA for its cloning.

A and B are two different cloning vectors in two different bacterial colonies cultured in chromogenic substrate Bacterial colonies with cloning vector A were colourless, whereas those with B were blue coloured. Explain by giving reasons the cause of difference in colour that appeared.

A plasmid DNA and a linear DNA (both of the same size) have one site for a restriction endonuclease. When cut and separated on agarose gel electrophoresis, plasmid shows one DNA band, while the linear DNA shows two fragments. Explain.

An alien piece of DNA needs to be integrated to a specific sequence of host DNA for its cloning. Is it true? if yes, explain. If this is DNA is not picked up by host cells. Can you suggest a reason for it?

What would happen if you grow a recombinant in a bioreactor but forget to add antibiotic to the medium in which the recombinant is growing?

(a) A recombinant vector with a gene of interest inserted within the gene of a-galactosidase enzyme, is introduced into a bacterium. Explain the method that would help in selection of recombinant colonies from non-recombinant ones.
(b) Why is this method of selection referred to as "insertional inactivation" ?

In Gel electrophoresis, the DNA fragments are placed in wells on a sheet of gelatin and an electric current is applied to the sheet. Based on DNA biochemistry in which side are the wells located? In which direction and why do the fragments migrate?

Agrobacterium tumifaciens is a pathogen of several dicot plants. But for biotechnologists it is a boon. Justify?

In nature A. tumifaciens which is called a natural genetic engineer, infects only dicots. Unfortunately many important crop plants are monocots and thus could not be easily transfacted. Scientists have discovered certain processes to introduce naked DNA molecules into the plant tissue that are not susceptible to A. tumefactions ? Explain any two.

After completion of the biosynthetic stage the products has to be subjected through a series
a) List these processes?
b) What are they collectively known as?
c) List any other measures to be taken care of?