‹ GCSE Combined and Separate Science
Inheritance, variation and evolution
Meiosis and DNA, Punnett squares and family trees, inherited disorders and embryo screening, natural selection, selective breeding, genetic engineering and cloning, and classification.
Start: Reproduction, meiosis and DNA About 20 min, free
Lessons
Practise and test
By the end you can
Use chromosome numbers, meiosis and 2ⁿ to count chromosomes and gamete combinations Describe transcription and translation with mRNA, tRNA, codons and anticodons (Edexcel Higher, Biology only) Complete Punnett squares and give probabilities, ratios and percentages of offspring Work out genotypes and chances from family trees, and evaluate embryo screening Explain variation, natural selection, antibiotic resistance and extinction Describe selective breeding, genetic engineering and cloning, with their benefits and risks Explain how restriction enzymes, sticky ends and ligase are used in genetic engineering (Edexcel Higher) Classify organisms and read evolutionary trees Explain sex-linked inheritance and find carriers in family trees (Edexcel Higher, Biology only), and decide from a family tree whether a condition is dominant or recessive Use rock layers, resistant bacteria, extinction data, human fossils and the pentadactyl limb as evidence for evolution Revision notes
Specifications AQA 8461 (Biology) 4.6AQA 8464 (Combined Trilogy) 4.6Pearson Edexcel 1BI0 and 1SC0 Topics 3 and 4OCR Gateway J247 and J250 B5 and B6
Next unit: Ecology Previous unit: Homeostasis and response
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