This lesson describes the behaviour of chromosomes during meiosis, focusing on the events which contribute to genetic variation. The detailed PowerPoint and accompanying resources have been designed to cover points 16.1 (a, d & e) of the CIE A-level Biology specification and explains how crossing over, the random assortment and the random fusion of haploid gametes leads to variation.
In order to understand how the events of meiosis like crossing over and independent assortment and independent segregation can lead to variation, students need to be clear in their understanding that DNA replication in interphase results in homologous chromosomes as pairs of sister chromatids. Therefore the beginning of the lesson focuses on the chromosomes in the parent cell and this first part of the cycle and students will be introduced to non-sister chromatids and the fact that they may contain different alleles which is important for the exchange that occurs during crossing over. Time is taken to go through this event in prophase I in a step by step guide so that the students can recognise that the result can be new combinations of alleles that were not present in the parent cell. Moving forwards, the lesson explores how the independent assortment and segregation of chromosomes and chromatids during metaphase I and II and anaphase I and II respectively results in genetically different gametes. The key events of all of the 8 phases are described and there is a focus on key terminology to ensure that students are able to describe genetic structures in the correct context. The final part of the lesson looks at the use of a mathematical expression to calculate the possible combinations of alleles in gametes as well as in a zygote following the random fertilisation of haploid gametes. Understanding and prior knowledge checks are interspersed throughout the lesson as well as a series of exam-style questions which challenge the students to apply their knowledge to potentially unfamiliar situations.
This lesson has been specifically planned to link to the two lessons on the cell cycle and the main stages of mitosis as covered in topic 5 and constant references are made throughout to encourage students to make links and also to highlight the differences between the two types of nuclear division
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The cell cycle, mitosis and meiosis (CIE A-level Biology)
The three lessons included in this bundle describe the key events of the mitotic and meiotic cell cycles and cover the following points as detailed in topics 5 and 16 of the CIE A-level Biology specification: Topic 5: The mitotic cell cycle * Explain the importance of mitosis in the production of genetically identical cells, growth, cell replacement, repair of tissues and asexual reproduction * Outline the cell cycle, including interphase, mitosis and cytokinesis * The behaviour of chromosomes in plant and animal cells during the mitotic cell cycle Topic 16: Inherited change * Explain what is meant by a pair of homologous chromosomes * The behaviour of chromosomes in plant and animal cells during meiosis * Explain how crossing over and random assortment of homologous chromosomes during meiosis and random fusion of gametes at fertilisation lead to genetic variation Each lesson is fully-resourced and the wide range of tasks found in the PowerPoint and the accompanying resources will check on current understanding and prior knowledge and engage the students with guided discussion points and quiz competitions. If you would like to sample the quality of lessons in this bundle, then download the interphase, mitosis and cytokinesis lesson as this has been uploaded for free
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Topic 16: Inherited change (CIE A-level Biology)
Meiosis, genetic inheritance and the control of gene expression are some of the harder topics on this A-level Biology course and all three are covered in topic 16 (Inherited change) of the CIE A-level Biology specification. The 10 lessons included in this bundle have been planned at length and contain a wide range of tasks that cover the detailed content whilst checking on understanding and key terms and values are introduced through engaging quiz competitions. The following topic 16 specification points are covered by these lessons: Topic 16.1 * The meaning of a homologous pair of chromosomes * The behaviour of chromosomes in animal and plant cells during meiosis * Genetic variation is caused by crossing over, random assortment and the random fusion of gametes at fertilisation Topic 16.2 * The meaning of key genetic terms * Using genetic diagrams to solve problems involving mohohybrid and dihybrid crosses, including those involving autosomal linkage, sex linkage, codominance, multiple alleles and gene interactions * Use the chi-squared test to test the significance of differences between observed and expected results * Gene mutations occur by substitution, deletion and insertion and may affect the phenotype Topic 16.3 * The genetic control of protein production in a prokaryote as shown by the lac operon * The function of transcription factors in gene expression in eukaryotes * Gibberellins and DELLA protein repressors If you would like to sample the quality of the lessons included in this bundle, then download the autosomal linkage and chi-squared test lessons as these have been uploaded for free
£15.00
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