Lesson #13 Translation

• What is transcriptional regulation?

  It is the control of gene expression at the transcription stage.

  
• How do prokaryotes regulate gene expression?

  They regulate gene expression in response to environmental changes.
• Why do eukaryotes regulate gene expression?

  To facilitate development and maintain homeostasis.

  
• What are the three mechanisms that finely control gene expression in all organisms?

  • Transcriptional regulation
  • Post-transcriptional regulation
  • Post-translational regulation

  
• What does transcriptional regulation depend on?

  It depends on the ability of RNA polymerase to interact with DNA.

  
• What is the most common form of gene expression regulation in prokaryotic and eukaryotic cells?

  Transcriptional regulation.

  
• What role do DNA binding proteins play in transcription initiation?

  They control transcription initiation.

  
• What is the promoter region?

  It is a regulatory DNA sequence upstream from the transcription start site.

  
• How does RNA polymerase bind to the core promoter?

  RNA polymerase binds to the core promoter region.

  
• What are the two types of transcriptional control?

  Positive control and negative control.

  
• What is positive control in transcriptional regulation?

  It is when activators bind to activator binding sites.

  
• What is negative control in transcriptional regulation?

  It is when repressors bind to operators.

  
• What are the components of operon regulation in prokaryotes?

  • Core promoter region
  • Activator binding sites
  • Operator

  
• What does the lac operon produce?

  Proteins required for lactose metabolism.

  
• What does the lac repressor protein do?

  It inhibits transcription when lactose is absent.

  
• What role does the CAP activator play in transcription?

  It promotes transcription when glucose is absent.
• What environmental condition is required for lac transcription?

  Lactose must be present in the environment.

  
• What does the trp repressor do?

  It inhibits transcription when tryptophan is available.

  
• How do molecules in the environment affect transcription?

  • Induction occurs when molecules stimulate transcription.
  • Repression occurs when molecules inhibit transcription.

  
• What are general transcription factors?

  They assemble at the core promoter and recruit RNA polymerase in eukaryotes.

  
• How can changing the availability of transcription factors regulate transcription in eukaryotes?

  It can affect the recruitment of RNA polymerase to the core promoter.

  
• What are specific transcription factors?

  They increase gene expression and may bind to enhancer elements.

  
• How does chromatin structure influence gene expression?

  Changes in chromatin structure affect the accessibility of DNA for transcription.

  
• What is alternative splicing?

  It allows different proteins to be produced from one mRNA.

  
• What is the significance of mRNA export regulation?

  It prevents translation of mRNA by regulating its export from the nucleus.

  
• How do small RNAs regulate gene expression?

  They bind to target mRNA to block translation or degrade it.

  
• What are the two types of small RNAs?

  Micro RNA (miRNA) and small-interfering RNA (siRNA).

  
• How is RNA interference (RNAi) used in research?

  It is used to selectively knock-down gene expression.
• What is ubiquitination?

  It is the addition of ubiquitin proteins to target proteins for degradation.
• What is the role of protein degradation in gene expression regulation?

  It removes unneeded or damaged proteins.
• What are the stages of gene expression regulation?

  • Transcriptional Regulation: What is transcribed?
  • Post-transcriptional Regulation: What is translated?
  • Post-translational Regulation: How does the protein function?