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प्रश्न
Describe briefly the following:
Origin of replication
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उत्तर
One of the most important components of a plasmid is the sequence of bases that initiates replication. It is known as the origin of replication (ori). This is a region of the plasmid genome that acts as a start signal for self-replication (making another copy of itself). Any portion of DNA connected to this sequence can be replicated within host cells. This characteristic is utilised to create multiple copies of linked DNA (or DNA inserts).
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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?
Why is the coding sequence of an enzyme β-galactosidase a preferred selectable marker in comparison to the ones named above?
Write the role of ‘restriction sites’ in the cloning vector pBR322.
Answer the following question.
β galactosidase enzyme is considered a better selectable marker. Justify the statement.
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 ______.
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 modification is done on the Ti plasmid of Agrobacterium tumefaciens to convert it into a cloning vector?
A plasmid without a selectable marker was chosen as vector for cloning a gene. How does this affect the experiment?
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.
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 “Ti plasmid” of Agrobacterium tumefaciens stands for ______.
