Prokaryotic Gene Regulation

Review Questions

If glucose is absent, but so is lactose, the lac operon will be ________.

  1. activated
  2. repressed
  3. activated, but only partially
  4. mutated

Hint:

B

Prokaryotic cells lack a nucleus. Therefore, the genes in prokaryotic cells are:

  1. all expressed, all of the time
  2. transcribed and translated almost simultaneously
  3. transcriptionally controlled because translation begins before transcription ends
  4. b and c are both true

Hint:

D

The ara operon is an inducible operon that controls the production of the sugar arabinose. When arabinose is present in a bacterium it binds to the protein AraC, and the complex binds to the initiator site to promote transcription. In this scenario, AraC is a(n) ________.

  1. activator
  2. inducer
  3. repressor
  4. operator

Hint:

A