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MEIOSIS Round 2

MEIOSIS Round 2. Compare. Critical differences between Mitosis and Meiosis: Tetrads form (Pro I) Crossing over can occur (Pro I) Tetrads line up and are separated (Meta I) Daughter cells are haploid Only occurs in germ cells Produces gametes (ova and sperm). Mitosis vs. Meiosis I.

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MEIOSIS Round 2

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  1. MEIOSIS Round 2

  2. Compare • Critical differences between Mitosis and Meiosis: • Tetrads form (Pro I) • Crossing over can occur (Pro I) • Tetrads line up and are separated (Meta I) • Daughter cells are haploid • Only occurs in germ cells • Produces gametes (ova and sperm)

  3. Mitosis vs. Meiosis I Left: Metaphase of MITOSIS: no pairing!!!! Right: Metaphase I of Meiosis: homologous chromosomes Pair UP!

  4. Independent Assortment

  5. Chromosome Mutations are spontaneous changes involving an entire chromosome or pieces of a chromosome Remember Mutations?

  6. Can occur during meiosis Some harmful, some not Bigger effect than gene mutations 2 types: Structural mutations and Numerical Mutations Chromosome Mutations

  7. change in arrangement of genes on a chromosome For example, Deletion- one or more genes are lost Structural Mutations

  8. Another example…. Inversion- piece of a chromosome breaks off and reattaches itself backwards Structural Mutations

  9. Another example, Duplication- extra piece duplicated genes Structural Mutations

  10. Another example, Translocation- piece of a chromosome breaks off of one & attaches to another different chromosome Structural Mutations

  11. QRSTUV to QRUTSV Inversion UVWXY to ABCDUVWXY Insertion/Addition LMNOP to LMNLMNOP Duplication ABCDEF to ABEF Deletion What TYPE of mutations are these? Structural - change in arrangement or # of genes What causes them? Problems with crossing over What’s the Mutation?

  12. changes in the number of chromosomes in a zygote Usually results from nondisjunction- failure of chromosomes to separate Monosomy- zygote receives only 1 of a particular chromosome EX: female being XO or getting 1 # 6 chromosome Numerical Mutations

  13. Trisomy- zygote receives 3 chromosomes of a particular kind Down’s Syndrome - extra 21st chromosome Numerical Mutations

  14. XXY - 47 Males The most common sexchromosome disorder. ~1/1000 males Males are usually infertile. Klinefelter’s Syndrome

  15. Polyploidy- none of the chromosomes separate and the zygote gets 3 or more sets of chromosomes EX: instead of 23 pairs, you get 46 pairs of chromosomes…this means 92 chromosomes!!! Numerical Changes

  16. 46 (23 pairs) What are pairs 1-22 called? Autosomes What is the 23rd pair called? Sex chromosomes Male? Female? XY XX How many chromosomes does a human have?

  17. Normal Karyotype

  18. Monosomy

  19. Trisomy

  20. Trisomy

  21. Trisomy

  22. Can you find the mistake?

  23. Can you find the mistake?

  24. Can you find the mistake?

  25. Can you find the mistake?

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