Multiple choice

With which of the following does the operator gene in an operon of a prokaryote (E. coli) combine?

  1. Repressor protein (to switch on gene action)

  2. Inducer gene (to switch off structural gene action)

  3. Inducer gene (to switch on structural gene action)

  4. Promoter gene (to start transcription of structural gene)

  5. Regulator or repressor protein (to switch off structural gene action)
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Regulator or repressor protein (to switch off structural gene action): In Lac operon as it is described by Jacob and Monad in E.coli, the operator gene combines with repressor tetramer produced on translation of mRNA transcripted from inducer or regulatory gene. It inhibits the RNA polymerase from running over the structural genes. This consequently switches off the functioning of the structural genes.

Keep practicing — related questions