• Quick retrieval from earlier learning (Prokaryotic and eukaryotic cells; DNA, genes and chromosomes). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Where is this found: mitochondria? (prokaryotic cells only / eukaryotic cells only / both types of cell) → eukaryotic cells onlyPrompt: “Pro-karyote” means “before nucleus”.
2. Rosalind Franklin's X-ray image helped scientists discover… (the first vaccine / the structure of DNA / penicillin / the shape of the Earth) → the structure of DNAPrompt: Watson and Crick used her data.
3. Which organism is made of prokaryotic cells? (yeast / E. coli bacteria / an amoeba / a mushroom) → E. coli bacteriaPrompt: Which one has no nucleus?

• Show a microscope image of cells and ask what students think they are looking at.
• Share the objective: Selective breeding, genetic engineering and gene editing. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: What does CRISPR-Cas9 allow scientists to do?
• Step 1: CRISPR uses guide RNA to direct Cas9 to a target sequence, where the DNA is cut and edited.
• Step 2: So the answer is: cut DNA at a chosen place to edit a gene precisely
• Answer: cut DNA at a chosen place to edit a gene precisely
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. What does CRISPR-Cas9 allow scientists to do? (make copies of whole animals / read a person's thoughts / remove all mutations from a population / cut DNA at a chosen place to edit a gene precisely) → cut DNA at a chosen place to edit a gene preciselyPrompt: Cas9 is an enzyme guided by a short piece of RNA.
2. Evaluate this claim: “Insect-resistant GM crops mean farmers never need to manage pests again.” Which response is best supported by evidence? (Insects cannot evolve. / Pests disappear forever after one season. / The crops kill every animal that touches them. / They can reduce insecticide spraying, but insects can evolve resistance, so careful management is still needed.) → They can reduce insecticide spraying, but insects can evolve resistance, so careful management is still needed.Prompt: Be wary of answers that use “never”, “every” or “always”.

• Students work on the student sheet. Circulate and check the first two answers of every student early.
• Students who finish: write a question of their own for a partner, with the answer.

The 8 questions are on the student sheet below, with answers in the key.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. Evaluate this claim: “GM crops are unsafe to eat.” Which response is best supported by evidence? (All GM crops are identical, so one test proves everything. / A website says so, so it must be true. / Large reviews of studies have found approved GM foods as safe as conventional foods, but each new crop is tested separately. / Nobody has ever tested GM food.) → Large reviews of studies have found approved GM foods as safe as conventional foods, but each new crop is tested separately.Prompt: Be wary of answers that use “never”, “every” or “always”.
2. Golden rice was genetically modified to make a substance the body turns into vitamin A. What problem does it aim to reduce? (antibiotic resistance / vitamin A deficiency, which can cause blindness / lack of protein / obesity) → vitamin A deficiency, which can cause blindnessPrompt: It targets places where rice is the main food.

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-11.