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.
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