6.5 Regulation of Gene Expression

• Transcription involves the use of DNA as a template to produce mRNA
• Where does transcription take place in a cell?

  Nucleus
• The lac operon in bacteria controls genes needed for lactose metabolism
• Why is gene regulation essential for cell differentiation?

  Specialized cell functions
• Dysregulation of gene expression can lead to diseases like cancer
• Promoters are DNA sequences that serve as binding sites for RNA polymerase
• What is an example of gene regulation preventing disease?

  Tumor suppressor genes
• What are transcription factors and how do they regulate gene expression?

  Bind to promoters or enhancers
• Enhancers are DNA sequences that increase the rate of transcription when bound by transcription factors
• RNA splicing involves the removal of introns and the joining of exons
• Gene expression involves transcription and translation


  True
• Match the role of gene regulation with its example:

  Cell Differentiation ↔️ Specialized neurons

  Environmental Adaptation ↔️ Lactose metabolism in bacteria

  Disease Prevention ↔️ Tumor suppressor genes
• Histone acetylation enhances gene transcription


  True
• Promoters are DNA sequences that serve as binding sites for RNA polymerase

  True
• Histone acetylation enhances transcription by opening chromatin
• What enzyme performs A-to-I editing during RNA editing?

  APOBEC
• What are epigenetic modifications?

  Changes to DNA and chromatin
• What chemical change to histones opens chromatin and activates gene expression?

  Acetylation
• Arrange the differences between prokaryotic and eukaryotic gene regulation based on complexity:

  1️⃣ Prokaryotic promoters are simpler

  2️⃣ Eukaryotic transcription factors bind to enhancers

  3️⃣ Operons are common in prokaryotes

  4️⃣ Chromatin structure affects eukaryotic gene expression
• In prokaryotes, DNA is wrapped around histones to form chromatin

  False
• What is an example of a prokaryotic operon?

  Lac operon
• What is gene expression?

  Functional gene product synthesis
• Translation occurs in the cytoplasm at the ribosome.

  True
• What is the template used during translation?

  mRNA
• Gene regulation allows organisms to adapt to environmental changes.


  True
• What are transcription factors and their role in gene regulation?

  Bind and activate/repress
• How does gene regulation contribute to cell specialization?

  Expressing specific genes
• The lac operon is activated when lactose is present.


  True
• Stronger promoters lead to higher gene expression


  True
• How does chromatin structure affect gene expression?

  Makes genes more or less accessible
• What is RNA editing and what enzyme performs A-to-I editing?

  Alters mRNA sequence; APOBEC
• During transcription, DNA is used as a template to produce mRNA
• What is the function of activators in gene regulation?

  Enhance transcription
• What are transcription factors?

  Proteins that bind to DNA
• Match the post-transcriptional mechanism with its description:

  RNA Splicing ↔️ Removes introns and joins exons

  RNA Editing ↔️ Alters mRNA nucleotide sequences

  mRNA Stability ↔️ Regulates mRNA longevity
• The poly(A) tail and UTRs of mRNA affect its stability and translation

  True
• DNA methylation generally represses gene expression
• Disruption of normal epigenetic regulation has been linked to diseases like cancer

  True
• What is a common sequence in prokaryotic promoters?

  TATA box