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Meiosis

Meiosis. Cell division – ‘ reduction division’ Production of sex cells – gametes. Why do we need meiosis?. Meiosis is necessary to halve the number of chromosomes going into the sex cells Why halve the chromosomes in gametes?

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Meiosis

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  1. Meiosis Cell division – ‘reduction division’ Production of sex cells – gametes

  2. Why do we need meiosis? • Meiosis is necessary to halve the number of chromosomes going into the sex cells Why halve the chromosomes in gametes? At fertilization the male and female sex cells will provide ½ of the chromosomes each – so the offspring has genes from both parents

  3. How many chromosomes does a human have? • chromosomes total- 46 • 23 from male sperm • 23 from female egg

  4. What is meiosis? • Meiosis has two rounds of cell division, meiosis I and meiosis II each subdivided into prophase, metaphase, anaphase and telophase. • Results in 4 daughter cells, each with half of the genetic material of the original cell.

  5. Parent cell Chromosomes are copied and double in number Chromosomes now split 2 daughter cells identical to original

  6. Meiosis Parent cell – chromosome pair Chromosomes copied 1st division - pairs split 2nd division – produces 4 gamete cells with ½ the original no. of chromosomes

  7. Meiosis – mouse Parent cell 1st division 2nd division 4 gametes

  8. Function of Meiosis • Meiosis is a process that occurs for the following functions: • To reduce the chromosome number from diploid to haploid. This is called a reduction division • To ensure that each haploid cell has a complete set of chromosomes • To promote genetic diversity because each cell is unique.

  9. Compare mitosis to meiosis

  10. Meiosis

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