Lesson 2: Biological Mechanisms: CRISPR, Gene Drives & Genetic Engineering
Demonstrating understanding of biological responses and human implications in a socio-scientific issue.
🎯 Ngā Whāinga Akoranga | Learning Intentions
Molecular biology mechanisms of gene editing: CRISPR-Cas9 target recognition, gRNA cleavage, non-homologous end joining vs HDR, and gene drives overriding Mendelian inheritance.
Diagram CRISPR-Cas9 molecular cleavage, explain how gene drives alter allele frequencies in wild populations, and evaluate off-target biological risks.
🎥 Media Anchor & Pedagogical Scaffold
Biotechnology Mechanics & Gene Editing Systems
Video Clip: Biotechnology innovation and socio-scientific issue analysis (Runtime: 3m 8s).
🧠 1. Before Viewing (Activate & Predict)
How does CRISPR-Cas9 allow precise genomic modifications compared to historical selective breeding and radiation mutagenesis?
👁️ 2. After the Clip (Work With a Job)
- Kōrero: Trace Cas9 endonuclease enzyme targeting guided by synthetic RNA sequences.
- Kōrero: Analyse how gene drives force a modified trait to spread through 100% of offspring.
- Kōrero: Evaluate ecological safety mechanisms (reversal drives, synthetic target sites).
🗣️ 3. After Viewing & Kaiako Move (Process & Apply)
Kaiako Move: Provide paper-cutout molecular models of Cas9, gRNA, and target DNA strands for hands-on simulation.
Immediate Task: Complete Section 2 of your Biology Portfolio: CRISPR-Cas9 Mechanism Diagram & Gene Drive Flowchart.
⚡ Whakaoho | Do Now: Socio-Scientific Concept Recall (10 mins)
Three billion base pairs. Cut exactly one place. That is the problem CRISPR solves.
Two minutes: before the mechanism is explained, propose how you would find one specific 20-letter sequence in a three-billion-letter text — and then cut it. Your answer will involve something that matches the target by base pairing. That something is the guide RNA.
📖 Activity 1: Biological Evidence & Ethical Analysis (25 mins)
Diagram the cut (15 min). Draw CRISPR-Cas9 acting on a target sequence: guide RNA, PAM site, the Cas9 cut, then the two repair routes. Label which route disables a gene and which inserts a new one, and say why the cell's own repair machinery determines the outcome.
Break Mendel (10 min). A normal heterozygous cross passes a gene to ~50% of offspring. Diagram what a gene drive does instead and calculate the spread over four generations. Then state plainly what makes this different in kind from ordinary genetic modification — it does not stay where you put it.
📝 Activity 2: Level 3 Biology (Internal) Report Drafting & Merit/Excellence Scaffolding (20 mins)
Report — Section 2. Submit: (1) an annotated CRISPR-Cas9 diagram with both repair pathways and their consequences; (2) your gene-drive inheritance calculation over four generations against the Mendelian baseline; (3) a paragraph on why self-propagation changes the risk assessment.
🏫 Kaiako Planning & Pedagogy Notes
NCEA Level 3 Alignment: Direct preparation for NCEA Level 3 Biology — Internal (Integrate biological knowledge to develop an informed response to a socio-scientific issue). Emphasise balanced consideration of alternative perspectives and justified conclusions for Merit/Excellence grades.