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प्रश्न
Describe the role of CaCl2 in the preparation of competent cells?
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उत्तर
CaCl2 is known to increase the efficiency of DNA uptake to produce transformed bactrial cells. The divalent Ca+2 ions supposedly create transient pores on the bactrial cell wall by which the entry of foreign DNA is facilitated into the bactrial cells.
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संबंधित प्रश्न
Name the selectable markers in the cloning vector pBR322. Mention the role they play.
Draw a schematic sketch of pBR 322 plasmid and label the following in it:
(a) Any two restriction sites.
(b) Ori and rop genes.
(c) An antibiotic resistant gene.
Can you think and answer how a reporter enzyme can be used to monitor the transformation of host cells by foreign DNA in addition to a selectable marker?
Describe briefly the following:
Origin of replication
Why is the coding sequence of an enzyme β-galactosidase a preferred selectable marker in comparison to the ones named above?
How does the β-galactosidase coding sequence act as a selectable marker? Why is it a preferred selectable marker to antibiotic resistance genes? Explain.
The genetic material of virus includes:
The colonies of recombinant bacteria appear white in contrast to blue colonies of non-recombinant bacteria because of ______.
A clone is a ______.
Which of the following is correctly matched?
Plasmids are suitable vectors for gene cloning because these ______.
Which of the following is not a genetic vector?
A cloning vector should possess which of the following characters?
- Origin of replication (Ori)
- Ability to destroy the alien DNA
- Cloning site to link the alien DNA
- The tumour inducing plasmid Ti.
- Selectable marker.
- Low molecular weight
The CORRECT combination is
Which of the following is not a cloning vector?
Plasmid pBR322 has a PstI restriction enzyme site within gene ampR that confers ampicillin resistance. If this enzyme is used for inserting a gene for β-galactoside production and the recombinant plasmid is inserted in an E.coli strain.
For selection of recombinants, insertional inactivation of antibiotic marker has been superceded by insertional inactivation of a marker gene coding for a chromogenic substrate. Give reasons.
Describe the role of Agrobacterium tumefaciens in transforming a plant cell.
The figure below shows the structure of a plasmid.
A foreign DNA was ligated at BamH1. The transformants were then grown in a medium containing antibiotics tetracycline and ampicillin.
Choose the correct observation for the growth of bacterial colonies from the given table.
