6.5 Regulation of Gene Expression
All organisms, whether prokaryotes or eukaryotes, must regulate which genes are expressed at any given time. Both unicellular organisms and the cells of multicellular organisms continually turn genes on and off in response to signals from their external and internal environments.
To Think About:
What is gene expression? What types of interactions regulate gene expression? What is epigenetics? How is the phenotype of a cell or organism influenced by differential gene expression? How does the location of regulatory sequences relate to their function? What is an operon? Why is the lac operon an inducible operon?
Watch: AP Daily Gene Expression Video One
Answer the Following Questions:
- What is gene expression?
- What are regulatory sequences and what is their function? (do NOT use the word “regulate” in your answer!)
- What is the function of regulatory proteins?
- The interaction of ______________ __________________ with ______________ ___________________________ controls ___________________
- Are epigenetic changes reversible?
- How are histones involved in regulation of gene expression?
- All cells in your body have the same ______________________
- What gives a cell in a tissue its function?
- What is cell differentiation?
- What is the function of transcription factors? How does this relate to cell differentiation?
Watch: AP Daily Gene Expression Video Two
Answer the Following Questions:
- What is an operon? What do all genes in an operon share?
- What is the function of the operator?
- Why is the lac operon called an “inducible” operon?
- Explain how the regulatory protein inhibits transcription of the lac operon.
- What are inducers? Explain how allolactose allows transcription to occur.
- When glucose levels are _____________ transcription factors promote transcription of the lac operon.
Supplementary Resources:
- Bozeman Science: Mr. Andersen’s “Gene Regulation” video
- Bozeman Science: Operon video
Sumanas: Animated lac operon
Nobelprize.org: The Nobel Prize in Physiology or Medicine 1965—Jacob, Lwoff and Monod (operons)
Bozeman Science: Epigenetics
- TED-Ed: What is Epigenetics?
- SciShow: “Can Your Environment Affect Your DNA”
University of Utah Genetic Science Learning Center: Epigenetics
Nobelprize.org: The Nobel Prize in Physiology or Medicine 2006—Fire and Mello (RNAi)
