Regulation and Transcription

• Regulation + Transcription

  • Multicellular organisms:
  • Every cell same genome + every protein code
  • Many cells are specialised, don’t need every protein
  • Waste energy to transcribe + translate genes
  • Some...
  • Genes always translated (constituent protein + respiration enzymes)
  • Only when required
  • Genes switched on + off (gene regulation)
  • Gene regulation controlled at 3 points:
  • Transcription (during mRNA production)
  • Post-transcription (after mRNA production)
  • Post-translational (after protein production)
• Transcription regulation Eurkaryotes

  • Regulatory proteins = transcription factors
  • Binds to correct DNA region, promoter
  • Transcription produce specific mRNA
  • Gene not expressed, inhibitor molecule bond complementary transcription factor, block promoter bind

  Hormones:

  • 2 mechanisms:
  • Protein hormones + secondary messenger molecule
  • Regulate transcription + translation (switch on gene); lipid-soluble hormones
  • Hormones bind to transcription factors’ receptors
  • Change shape + release inhibitor molecule
  • Now bind to promoter DNA region on DNA
  • Enable RNA polymerase to begin transcription