Advertisements
Advertisements
प्रश्न
Answer the following question.
β galactosidase enzyme is considered a better selectable marker. Justify the statement.
Advertisements
उत्तर
The selective marker is used in the selection of recombinants on the basis of the ability to produce colour in the presence of a chromogenic substrate. β-galactosidase is an enzyme that converts galactose into lactose. In this, a recombinant DNA is inserted within the coding sequence of enzyme, β-galactosidase, which results in inactivation of an enzyme referred to as "insertional inactivation".
The coding sequence for the enzyme β-galactosidase is preferred over antibiotic resistance genes because recombinants can be easily visualized.
APPEARS IN
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.
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?
Explain the importance of ‘Selectable marker’, with the help of a suitable example.
Answer the following question.
Expand ‘YAC’ and mention what it was used for.
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
What modification is done on the Ti plasmid of Agrobacterium tumefaciens to convert it into a cloning vector?
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For selection of recombinants, insertional inactivation of antibiotic marker has been superceded by insertional inactivation of a marker gene coding for a chromogenic substrate.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.
