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Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYMolecular Basis of Inheritance3 Marks
Question
Where is an 'operator' located in a prokaryote DNA? How does an operator regulate gene expression at transcriptional level in a prokaryote? Explain.
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Answer

The operator region is located adjacent to promoter elements/prior to structural gene. In regulation of gene expression.
  • Switch off- The repressor binds to the operator region, & prevents transcription.
  • Switch on- In the presence of inducer the repressor is inactivated, (by the interaction with the inducer) and operator allows RNA polymerase access to the promoter, & transcription proceeds.

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