Class 12th Biology 2012 Set3 Delhi Board Paper Solution
Question 19
(a) Construct a complete transcription unit with promotor and terminator on the basis of the hypothetical template strand given below:
(b) Write the RNA strand transcribed from the above transcription unit along with its polarity.
OR
How are the structural genes inactivated in lac operon in E. Coli? Explain.
(a) Construct a complete transcription unit with promotor and terminator on the basis of the hypothetical template strand given below:
(b) Write the RNA strand transcribed from the above transcription unit along with its polarity.
OR
How are the structural genes inactivated in lac operon in E. Coli? Explain.
Answer
(a)
(b) RNA strand transcribed from above transcription unit.
(c) In the absence of lactose, no inactivation of repressor occurs and hence the repressor (which is constitutively produced from i gene) binds to the operator region of the operon; thus preventing RNA polymerase from transcribing the operon thus inactivating of the production of structural genes in E.coli occurs.
Popular Questions of Class 12th biology
- Q:- What is spermatogenesis? Briefly describe the process of spermatogenesis.
- Q:- Why is reproduction essential for organisms? Answer
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals. - Q:- With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.
- Q:- What is DNA fingerprinting? Mention its application.
- Q:- What is oogenesis? Give a brief account of oogenesis.
- Q:- Describe the structure of a seminiferous tubule.
- Q:- What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.
- Q:- With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
- Q:- Explain the Law of Dominance using a monohybrid cross.
Recently Viewed Questions of Class 12th biology
- Q:- How did Hershey and Chase differentiate between DNA and protein in their experiment while proving that DNA is the genetic material?
- Q:- Differentiate between a zoospore and a zygote.
- Q:- Describe briefly the followings:
(a) Origin of replication
(b) Bioreactors
(c) Downstream processing - Q:- What initiatives were taken for reducing vehicular air pollution in Delhi? Has air quality improved in Delhi?
- Q:-
Why is the Human Genome project called a mega project?
- Q:- Differentiate between gametogenesis from embryogenesis.
- Q:- In our society the women are often blamed for giving birth to daughters.
Can you explain why this is not correct? - Q:- With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.
- Q:- Two heterozygous parents are crossed. If the two loci are linked what would be the distribution of phenotypic features in F1 generation for a dihybrid cross?
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals.