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प्रश्न
A plasmid without a selectable marker was chosen as vector for cloning a gene. How does this affect the experiment?
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उत्तर
In a gene, cloning experiment, first a recombinant DNA molecule is constructed, where the gene of interest is ligated to the vector (the step would not be affected) and introduced inside the host cell (transformation). Since, not all the cells get transformed with the recombinant/plasmid DNA, in the absence of a selectable marker, it will be difficult to distinguish between transformants and non-transformants, because role of the selectable marker is in the selection of transformants.
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संबंधित प्रश्न
State how has Agrobacterium tumifaciens been made a useful cloning vector to transfer DNA to plant cells.
Why is the coding sequence of an enzyme β-galactosidase a preferred selectable marker in comparison to the ones named above?
Explain the importance of ‘Selectable marker’, with the help of a suitable example.
How does the β-galactosidase coding sequence act as a selectable marker? Why is it a preferred selectable marker to antibiotic resistance genes? Explain.
A clone is a ______.
Which of the following statement is not true for a clone?
Plasmids are suitable vectors for gene cloning because these ______.
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
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.
What does ‘competent’ refer to in competent cells used in transformation experiments?
Describe the role of CaCl2 in the preparation of competent cells?
For selection of recombinants, insertional inactivation of antibiotic marker has been superceded by insertional inactivation of a marker gene coding for a chromogenic substrate.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.
The following diagram showing restriction sites in E. coli cloning vector pBR322. Find the role of ‘X’ and ‘Y’ genes:
The “Ti plasmid” of Agrobacterium tumefaciens stands for ______.
What is the primary role of a cloning site in a vector?
In blue–white screening, what do the white colonies indicate?
