Biology · Grade 12

Active learning ideas

CRISPR-Cas9 Gene Editing

Active learning works because CRISPR-Cas9 involves complex, multi-step processes that students grasp more deeply through hands-on modeling and collaborative analysis. Students benefit from seeing how guide RNA and Cas9 interact at the molecular level, which abstract concepts can obscure when taught through lecture alone.

• Ontario Curriculum Expectations
• HS-LS3-1

• 35–60 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Case Study Analysis
• 45 min · Pairs

Modeling Lab: Bead-Based CRISPR Simulation

Provide students with colored beads for DNA strands, pipe cleaners for guide RNA, and scissors for Cas9. In pairs, they assemble a target sequence, bind the RNA, cut at the match, and repair with new beads. Groups share results and discuss accuracy challenges.

How has the CRISPR-Cas9 system revolutionized our ability to edit genomes?

Facilitation Tip

During the bead-based simulation, rotate among groups to ask probing questions that connect their physical steps to the biological process, such as 'How does changing the guide RNA sequence affect the cut location?'

What to look for

Pose the following to small groups: 'Imagine you are advising a government committee on regulating CRISPR germline editing. What are the two most significant ethical concerns you would highlight, and what is one potential benefit that might justify its use under strict conditions?'

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

Activity 02

• Case Study Analysis
• 50 min · Small Groups

Case Study Rotation: Therapeutic Applications

Prepare stations with cases on sickle cell treatment, cancer therapies, and crop improvements. Small groups rotate, reading evidence, noting mechanisms, and predicting outcomes. Each group presents one key takeaway to the class.

Analyze the ethical considerations surrounding the use of CRISPR for human germline editing.

Facilitation Tip

For the case study rotation, assign each group a different application and require them to present a one-slide summary with a key takeaway, ensuring accountability and peer learning.

What to look for

Provide students with a diagram showing a target DNA sequence and a CRISPR-Cas9 complex. Ask them to label the Cas9 enzyme, the guide RNA, and the target DNA sequence. Then, ask them to predict what type of mutation might result if the cell primarily uses NHEJ for repair.

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

Activity 03

• Case Study Analysis
• 60 min · Whole Class

Ethical Debate: Germline Editing

Divide class into pro and con teams on human germline editing. Teams research arguments using provided articles, prepare 3-minute speeches, and rebuttals. Conclude with a whole-class vote and reflection on evidence strength.

Predict the potential therapeutic applications of CRISPR in treating genetic diseases.

Facilitation Tip

In the ethical debate, provide a structured rubric for arguments and counterarguments, and assign roles to ensure all students participate meaningfully.

What to look for

On a slip of paper, have students write: 1) One specific application of CRISPR-Cas9 they find most promising, and 2) One question they still have about the technology or its implications.

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

Activity 04

• Case Study Analysis
• 35 min · Individual

Digital Simulation: CRISPR Design Challenge

Use free online tools like Benchling for students to design guide RNAs for a mock gene. Individually input sequences, predict cuts, and evaluate off-target risks. Follow with pair discussions on designs.

How has the CRISPR-Cas9 system revolutionized our ability to edit genomes?

Facilitation Tip

During the digital simulation, circulate to troubleshoot technical issues and ask students to articulate their design choices before finalizing their CRISPR construct.

What to look for

Pose the following to small groups: 'Imagine you are advising a government committee on regulating CRISPR germline editing. What are the two most significant ethical concerns you would highlight, and what is one potential benefit that might justify its use under strict conditions?'

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

A few notes on teaching this unit

Teachers should emphasize iteration in CRISPR design, mirroring real-world research where experiments often require repetition. Avoid presenting CRISPR as a simple 'cut-and-paste' tool; instead, stress the variability in repair outcomes and the need for validation steps. Research shows students retain concepts better when they analyze real data, so incorporate short excerpts from primary literature or lab reports alongside activities.

Successful learning looks like students accurately describing the role of guide RNA and Cas9, explaining potential off-target effects, and evaluating real-world applications with ethical considerations. They should also demonstrate the ability to design a basic CRISPR experiment and critique its feasibility.

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Watch Out for These Misconceptions

• During the bead-based CRISPR simulation, watch for students assuming every cut leads to a precise edit without errors.

  Use the simulation to demonstrate mismatch risks by giving groups guide RNA strips with partial matches to the DNA sequence, then discuss how off-target cuts could occur and why validation steps are necessary.

• During the ethical debate on germline editing, watch for students believing CRISPR can create entirely new genes.

  Have students role-play cellular repair pathways during the debate prep, using analogies like 'NHEJ is like gluing broken DNA ends that may not fit perfectly,' to clarify that CRISPR primarily modifies existing sequences.

• During the case study rotation, watch for students assuming CRISPR is only used in human medicine.

  Assign case studies from diverse fields like agriculture or bacterial engineering, and ask groups to identify patterns in application across organisms before presenting their findings.

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Methods used in this brief

• Case Study Analysis