DNA Transcription (IB Topic D1.2)
Essential Idea(s): Information stored as a code in DNA is copied into mRNA. Cells can control when and where specific genes are expressed through mechanisms like alternative splicing.
Unit Length: 3 Lessons (+2 AHL)
Guiding Questions
◊ How does a cell produce a sequence of amino acids from a sequence of DNA bases?
◊ How is the reliability of protein synthesis ensured?
| IB Statement(s) and Objective(s) |
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D1.2.1: Transcription as the synthesis of RNA using a DNA template
D1.2.2: Role of hydrogen bonding and complementary base pairing in transcription
D1.2.3: Stability of DNA templates
D1.2.4: Transcription as a process required for the expression of genes
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Additional Higher Level Topics D1.2.12: Directionality of transcription and translation
D1.2.13: Initiation of transcription at the promoter
D1.2.14: Non-coding sequences in DNA do not code for polypeptides
D1.2.15: Post-transcriptional modification in eukaryotic cells
D1.2.16: Alternative splicing of exons to produce variants of a protein from a single gene
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| Activities: ⓟ = podcast / ⍰ = inquiry 5 / ⓦ = Write it / Ӕ = The academy / Ⓡ = Read it |
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Virtual Lab Worksheet (Recommended): Central Dogma, Disease, and Genetic Medicine (💁 / 👭 max 3) In groups of 2-3, go through this interactive presentation on genetic medicine. Once you finish, complete questions 1-2 on this worksheet. Your group will then be assigned one of the genetic medicines being developed in hopes of treating this disease. With your group, complete question 3 – and be ready to teach about your disease to the rest of the group.
Ⓛ (recommended): Extracting DNA from peas (💁/ 👭max 2) Extracting DNA from a living organism (in this case, peas) is actually easier than it seems. Follow the directions on this lab and see how much you can get. The end result will be simple, but stasifying – you’ll have a spool of thin DNA stuck to a glass rod.
Ⓛ +Ӕ (recommended): An Interactive Journey through the Central Dogma (💁) Work your way through this interactive lesson on transcription and translation. Then do it a 2nd time, only this time, screencast a recording of you teaching the content as you work your way through the app. Your final product should be a recording of your screen as you work through the app, with your voice explaining what you’re doing at each step.
ⓟ (recommended): The DNA Revolution (👭 max 3) / Note: this can also be done in the next unit – Mutations and Gene Editing (D1.3) The discovery of DNA was just the beginning. In 2012, CRISPR finally unlocked the ability that was previously science fiction: the ability to freely edit DNA. Discuss the implications of the history of DNA: Choose either a historical moment in DNA’s history (e.g. Franklin and Wilkins), OR the outlook for the future of DNA technology – and make your finest podcast to date. Follow the directions on this assignment sheet.
Old school worksheet (Recommended): Central Dogma, Disease, and Genetic Medicine (💁 / 👭 max 3) In groups of 2-3, go through this interactive presentation on genetic medicine. Once you finish, complete questions 1-2 on this worksheet. Your group will then be assigned one of the genetic medicines being developed in hopes of treating this disease. With your group, complete question 3 – and be ready to teach about your disease to the rest of the group.
📄: (Old-School Worksheet): Breaking the Genetic Code (💁) This worksheet will help you get familiar with a lot of the terms from levels 15-17 (think: codon, mRNA, transcription, translation, genetic code). Use it for practice!
ⓦ: “Inquiry 5″: Q&A on Central Dogma (💁/ 👭max 2) Create a list of 5 inquiry questions related to the central dogma of biology. Remember that good inquiry questions are conceptual / open-ended… Such as: “How can the change in a single nucleotide result in a genetic disorder that affects the whole body? NOT: “What is the function of mRNA?” If working solo, write out answers to your own questions; if working in pairs, record yourselves asking each other your 5 questions.
—————————————– Activities for Gene Expression:
ⓟ/ⓦ: 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”?
📄(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.
ⓦ: The Story of the Octopus & the Splicing RNA (💁) Read this very short article on Octopuses, and write a response that aligns with the content in this level. Discuss: 1) Why do octopuses need to regulate their gene expression?; 2) Why do octopus need to express different genes at different times?; and 3) How do they control their gene expression (read on to part II of this level to answer this).
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