Question
How do antibiotic-resistance genes function as selectable markers? Explain with the help of E.coli cloning vector pBR 322.
✓
Answer
- If a foreign DNA is ligated at the BamH I site of tetracyclin-resistance gene in the pBR 322, the recombinant plasmid will lose the tetracycline-resistance.
- The transformant can be selected out from the nontransformants by culturing on a medium containing ampicillin.
- The transformants are transferred to a culture medium containing tetracyclin; there they fail to grow but non-transformants grow in tetracyclincontaining medium as well as ampicillin-containing medium.
- Here, one antibiotic gene facilitates selection of transformants, while the other antibiotic gene gets inactivated by the insertion of alien DNA and facilitates selecting the recombinants.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
What are transgenic bacteria? Illustrate using any one example.
Given below is the representation of amino acid composition of the relevant translated portion of b-chain of haemoglobin, related to the shape of human red blood cells.
Name and explain the surgical method advised to human males and females as a means of birth control. Mention its one advantage and one disadvantage.
During a school trip to ‘Rohtang Pass’, one of your classmate suddenly developed ‘altitude sickness’. But, she recovered after some time.
- Mention one symptom to diagnose the sickness.
- What caused the sickness?
- How could she recover by herself after some time?
Name the fluid which protects an embryo.
What is high altitude sickness? Write its symptoms.
- Why must a cell be made 'competent’ in biotechnology experiments? How does calcium ion help in doing so?
- State the role of ‘biolistic gun’ in biotechnology experiments.
- Do all pollen grains remain viable for the same length of time? Support your answer with two suitable examples.
- How are pollen grains stored in pollen banks? State the purpose of storing pollen grains in these banks.
Write a short note on
Effects of temperature or water scarcity and the adaptations of animals
Effects of temperature or water scarcity and the adaptations of animals
For a layman, both apple and banana are fruits. But a biology student categorises fruits as true fruits, false fruits and parthenocarpic fruits. Justify.