• 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. Rosalind Franklin's X-ray image helped scientists discover… (penicillin / the structure of DNA / the first vaccine / the shape of the Earth) → the structure of DNAPrompt: Watson and Crick used her data.
3. Scientists put a human insulin gene into bacteria. Which bacterial structure is used to carry the gene? (a chloroplast / the nucleus / a mitochondrion / a plasmid) → 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. Farmers breed only the cows that give the most milk, generation after generation. What is this called? (cloning / genetic engineering / natural selection / selective breeding (artificial selection)) → selective breeding (artificial selection)Prompt: Humans choose which animals reproduce.
2. Evaluate this claim: “Gene therapy can cure every inherited disease.” Which response is best supported by evidence? (It changes the genes of every person on Earth. / Some gene therapies are approved for specific conditions, but many diseases are still being researched. / It only works on plants. / It has never helped anyone.) → Some gene therapies are approved for specific conditions, but many diseases are still being researched.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. Evaluate this claim: “Selective breeding is new and unnatural.” Which response is best supported by evidence? (Humans have selectively bred crops and animals for thousands of years; for example, maize was bred from a wild grass called teosinte. / It only works on bacteria. / It was invented in the last ten years. / It uses CRISPR to cut DNA.) → Humans have selectively bred crops and animals for thousands of years; for example, maize was bred from a wild grass called teosinte.Prompt: Be wary of answers that use “never”, “every” or “always”.
2. What does CRISPR-Cas9 allow scientists to do? (make copies of whole animals / cut DNA at a chosen place to edit a gene precisely / remove all mutations from a population / read a person's thoughts) → cut DNA at a chosen place to edit a gene preciselyPrompt: Cas9 is an enzyme guided by a short piece of RNA.

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