Short Answer Type(a) Name the selectable markers in the cloning vector pBR322 ? Mention the role they play.
(b) Why is the coding sequence of an enzyme 
-galactosidase a preferred selectable marker in comparison to the ones named above ?
(a) Selectable markers in the coming vectors pBR322 :
i. Ampicillin resistance antibiotics
ii.Tetracycline
(b) The selection of recombinants due to inactivation of antibiotics is a difficult process and requires simultaneous plating on two plates having different antibiotics. Thus, to differentiate between the non-recombinants and recombinants The enzyme 
- galactosidase is preferred as a selectable marker as it allows the person to differentiate the non-recombinants from recombinants. in this case when the recombinant DNA is inserted into the coding sequence of the enzyme 
-galactosidase. The insertion leads to the inactivation of the enzyme and hence in the presence of a chromogenic substance the recombinants do not give coloured colonies, while the non-recombinants produce blue colonies. Thus no separate plating is required.
Suggest and describe a technique to obtain multiple copies of a gene of interest in vitro.
Long Answer TypeA. Describe the characteristics a cloning vector must possess.
B. Why DNA cannot pass through the cell membrane? Explain. How is a bacterial cell made competent to take up recombinant DNA from the medium?
If a desired gene is identified in an organism for some experiments, explain the process of the following:
(i) Cutting this desired gene at specific location
(ii) Synthesis of multiple copies of this desired gene
Short Answer Type
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