This lesson describes the inheritance of two non-interacting unlinked genes and guides students through the calculation of phenotypic ratios. The PowerPoint and the accompanying question sheet (which is differentiated) have been designed to cover point 8.2 (iii) of the Edexcel A-level Biology B specification.
As the previous lesson described the construction of genetic crosses and pedigree diagrams, students are aware of the methods involved in writing genotypes and gametes for the inheritance of a single gene. Therefore, the start of this lesson builds on this understanding to ensure that students recognise that genotypes contain 4 alleles and gametes contain 2 alleles when two genes are inherited. The students are taken through the steps of a worked example to demonstrate the key steps in the calculation of a phenotypic ratio before 2 exam-style questions challenge them to apply their newly-acquired knowledge. Mark schemes are displayed within the PowerPoint to allow students to assess their progress. The phenotypic ratio generated as the answer to the final question is 9:3:3:1 and time is taken to explain that this is the expected ratio when two heterozygotes for two genes are crossed which they may be expected to use when meeting the chi squared test in an upcoming lesson
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Topic 8: Origins of genetic variation (Edexcel A-level Biology B)
This lesson bundle contains 10 lessons which are fully-resourced and have been designed to cover the content as detailed in topic 8 of the Edexcel A-level Biology B specification (Origins of genetic variation). Each lesson includes a wide range of activities that will engage and motivate the students whilst covering the following topic 8 specification points: * Mutations are the source of new variations * Random assortment and crossing over in meiosis give rise to new combinations of alleles in gametes * Random fertilisation brings about genetic variation * The meaning of genetic terms * Be able to construct genetic crosses and pedigree diagrams * The inheritance of two non-interacting unlinked genes * Autosomal linkage as the presence of alleles on the same chromosome * Sex linkage on the X chromosome * Use the chi squared test to determine the significance of the difference between observed and expected results * Stabilising and disruptive selection * Genetic drift * Population bottlenecks and the founder effect * Monitoring changes in allele frequencies using the Hardy Weinberg equation If you would like to sample the quality of the lessons in this bundle then download the sex linkage and genetic drift lessons as these have been uploaded for free
£15.00
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Topic 8.2: Transfer of genetic information (Edexcel A-level Biology B)
Each of the 6 specification points in topic 8.2 of the Edexcel A-level Biology B specification are covered by the 6 lessons included in this bundle: (i) Understanding of the key genetic terms (ii) Be able to construct genetic crosses and pedigree diagrams (iii) Understand the inheritance of two non-interacting unlinked genes (iv) Understand that autosomal linkage results from the presence of alleles on the same chromosome (v) Understand sex linkage on the X chromosome (vi) Be able to use the chi squared test The lessons contain step by step guides that walk students through the key details of this topic, such as the construction of genetic crosses or the calculation of the chi squared value. There are also lots of exam-style questions to challenge the students to apply their understanding and the mark schemes that are embedded in the PowerPoints will allow them to assess their progress. The sex linkage lesson has been uploaded for free if you would like to sample the quality of lessons in this bundle.
£9.50
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