19.2 Control of gene expression

• Give one way of transcriptional gene regulation.

  Transcription factors
• What are transcription factors?

  Proteins or non-coding RNA that regulate the transcription of genes
• What 2 areas do transcription factors bind to?

  Promoters, enhancers
• What has happened if a transcription factor has repressed a gene?

  The TF has attached to the promoter, preventing the attachment of RNA polymerase and expression of the gene
• What has happened if a transcription factor has up-regulated a gene?

  The TF has attached to the enhancer, aiding the attachment of RNA polymerase to the promoter and expression of the gene
• Give one way of post-transcriptional gene regulation.

  Maturing of mRNA through removal of introns
• What is an intron?

  A non-coding region of DNA / RNA
• What is an exon?

  A coding region of DNA / RNA
• What is pre-mRNA?

  mRNA containing both introns and exons
• What is mature mRNA?

  mRNA containing only exons (introns have been removed)
• What is alternative splicing?

  The joining of exons in a region of mRNA in different combinations resulting in one gene encoding more than one protein
• Give one way of translational gene regulation that up-regulates translation.

  Activating initiation factors (through phosphorylation by kinases) to help mature mRNA to bind to ribosomes
• Give one way of translational gene regulation that inihibits translation.

  Degrade mRNA / Inhibition proteins bind to mRNA to prevent it from binding to ribosomes
• Give one way of post-translational gene regulation.

  Cyclic AMP to activate CRP or kinases / protein modification or further folding
• What enzyme catalyses the formation of cyclic AMP from ATP?

  Adenyl cyclase
• What activates protein kinase A (PKA)?

  Cyclic AMP
• What is the function of protein kinase A (PKA)? 


  Activate enzymes / transcription factor proteins by phosphorylation