• 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: a single loop of DNA not in a nucleus? (prokaryotic cells only / eukaryotic cells only / both types of cell) → prokaryotic cells onlyPrompt: “Pro-karyote” means “before nucleus”.
2. Where is DNA found in an animal cell? (outside the cell / in the chloroplasts / in the cell wall / mainly in the nucleus) → mainly in the nucleusPrompt: It is the control centre of the cell.
3. Scientists put a human insulin gene into bacteria. Which bacterial structure is used to carry the gene? (the nucleus / a mitochondrion / a plasmid / a chloroplast) → a plasmidPrompt: Bacteria have small extra rings of DNA.

• 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. A problem with selective breeding is… (it is always too fast / it uses radioactive materials / inbreeding, which reduces variation and can increase inherited disorders / it creates new species every year) → inbreeding, which reduces variation and can increase inherited disordersPrompt: Think about breeding closely related animals.
2. Evaluate this claim: “GM crops are unsafe to eat.” Which response is best supported by evidence? (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. / A website says so, so it must be true. / All GM crops are identical, so one test proves everything.) → 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”.

• 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 6 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. Farmers breed only the cows that give the most milk, generation after generation. What is this called? (selective breeding (artificial selection) / natural selection / cloning / genetic engineering) → selective breeding (artificial selection)Prompt: Humans choose which animals reproduce.
2. Evaluate this claim: “GM crops are unsafe to eat.” Which response is best supported by evidence? (Large reviews of studies have found approved GM foods as safe as conventional foods, but each new crop is tested separately. / A website says so, so it must be true. / Nobody has ever tested GM food. / All GM crops are identical, so one test proves everything.) → 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”.

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