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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
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
Write the role of ‘restriction sites’ in the cloning vector pBR322.
Explain the importance of ‘Selectable marker’, with the help of a suitable example.
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?
Which of the following statement is not true for a clone?
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.
What does ‘competent’ refer to in competent cells used in transformation experiments?
What modification is done on the Ti plasmid of Agrobacterium tumefaciens to convert it into a cloning vector?
Name the regions marked A, B and C.
Which of the following enzyme(s) are NOT essential for gene cloning?
- Restriction enzymes
- DNA ligase
- DNA mutase
- DNA recombinase
- DNA polymerase
Choose the correct answer from the options given below:
The following diagram showing restriction sites in E. coli cloning vector pBR322. Find the role of ‘X’ and ‘Y’ genes:
