Question
A and B are two different cloning vectors in two different bacterial colonies cultured in chromogenic substrate. Bacterial colonies with cloning vector A were colourless, whereas those with B were blue coloured. Explain by giving reasons the cause of difference in colour that appeared.

Answer

On the basis of colour production in the presence of chromogenic substrate, the recombinants and non-recombinants cal be differentiated. In this, a recombinant DNA is inserted within coding sequence of an enzyme $\beta-$galactosidase, which results in inactivation of enzyme.
In plate A, the bacterial colonies having inserted plasmid, shows no colouration. While in plate B, insertion of plasmid does not occur, therefore it shows blue colour.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Explain with example how transformed host cells are selected from non- transformed?
The steps in a programme are:
  • Collection of germplasm.
  • Cross breeding the selected parents.
  • Selecting superior recombinant progeny-Testing, releasing and marketing new cultivars.
  1. What is this programme related to?
  2. Name two special qualities as basis of selection of the progeny.
  3. What is the popular term given to this outcome? Also name the Indian scientist
  4. who is credited with chalking out this programme?
Name the germinal layers from which the following organs develop. Tongue, Heart, Sweat gland, vagina. Mammary gland, Kidney
Give scientific reasons: Castor seed is endospermic or albuminous.
Double fertilisation is reported in plants of both, castor and groundnut. However, the mature seeds of groundnut are non-albuminous and castor are albuminous. Explain the post-fertilisation events that are responsible for it.
Archaeopteryx is called connecting link between reptiles and birds.
Suresh is doing his studies on a plant related to absorption of water. He found different forms of water available in the soil.
(i) Name them.
(ii) Which form of water is absorbed by the plants?
(iii) Name the region in the soil from where roots absorb water.
What is meant by recalcitrant seeds? How such plants can be conserved?
  1. Name two varieties of cauliflower that are resistant to Black rot disease. Name another disease, which these two varieties are resistant to.
  2. What is the major constraint in the conventional method of breeding for disease-resistance?
  1. Draw a diagram of a sectional view of a monocot seed (grain).
  2. Label and write the function of: Coleoptile, Coleorrhiza, Endosperm.