Gene Expression
(Topic D2.2 – AHL Only)
Essential Idea(s): Cells can control when and where specific genes are expressed through mechanisms like transcription, translation, and epigenetic modifications. All of these can be affected by environmental factors without altering the DNA sequence.
Unit Length: 4 Lessons (AHL Only)
Guiding Questions
◊ How is gene expression changed in a cell?
◊ How can patterns of gene expression be conserved through inheritance?
| IB Statement(s) and Objective(s) |
|---|
|
D2.2.1: Gene expression as the mechanism by which information in genes has effects on the phenotype
D2.2.2: Regulation of transcription by proteins that bind to specific base sequences in DNA
D2.2.3: Control of the degradation of mRNA as a means of regulating translation
D2.2.5: Differences between the genome, transcriptome and proteome of individual cells
D2.2.6: Methylation of the promoter and histones in nucleosomes as examples of epigenetic tags
D2.2.7: Epigenetic inheritance through heritable changes to gene expression
D2.2.8: Examples of environmental effects on gene expression in cells and organisms
D2.2.9: Consequences of removal of most but not all epigenetic tags from the ovum and sperm
D2.2.10: Monozygotic twin studies
D2.2.11: External factors impacting the pattern of gene expression
|
|
Activities: ⓟ = podcast / ⍰ = inquiry 5 / ⓦ = Write it / Ӕ = The academy / Ⓡ = Read it |
|---|
|
ⓟ/ⓦ: Biotech and the Discovery of DNA Expression (💁/ 👭 max 2) Watch this video on transcription and the biotech behind the study of gene expression. Discuss/write a response, answering: 1) What is gene expression?; 2) What is happening in the clips where glowing green/red spots can be seen? 3) What are transcription factors, and how are genes turned “on” or “off”?
Ⓛ (Lab): Controlling Gene Expression in E. Coli (💁/ 👭 max 2) In this lab, you’ll take on the role of a geneticist and actually switch on genes of E. Coli bacteria by manipulating their environment. This is a straightforward lab but does require careful attention to detail, all of which is provided. Make sure you give us a heads up in advance (2-3 days) if you want to prep the materials. No lab report is required here – just do the lab and submit answers to the questions at the end of the instructions!
ⓟ/ⓦ: The Lingering Mysteries of the Dutch Hunger Winter (💁/ 👭 max 2) It sometimes seems like one of nature’s cruelest tricks – as if the Dutch Hunger Winter wasn’t hard enough on those who suffered through it, new evidence of epigenetics suggests that the children of parents who suffered through that winter still carry certain epigenetic consequences from it, such as higher body mass index (BMI) and disrupted metabolism. Read through the article and discuss questions such as: 1) How does the Dutch Hunger Winter provide a natural experiment for studying the effects of prenatal environmental factors on long-term health?; 2) What role do methyl groups play in gene expression, and how could famine during pregnancy lead to epigenetic changes in offspring?; 3) Why is it significant that the Dutch Hunger Winter cohort showed consistent methylation patterns across different types of cells (e.g., blood, muscle, fat)?
📄(old school worksheet): Alternative Splicing Activity (💁) Grab some colored pencils — in this activity, you will use them to color-code different players in gene expression. You’ll label exons and see the different possible gene expressions from a single DNA sequence.
Extra Resources: |