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Warm Up #6 2/08

Warm Up #6 2/08. What happens to the chromosome # in mitosis ? What happens to the chromosome # in meiosis ? What is the abbreviation for the steps in mitosis ? What’s the abbreviation for the steps in meiosis ?

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Warm Up #6 2/08

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  1. Warm Up #6 2/08 • What happens to the chromosome # in mitosis? • What happens to the chromosome # in meiosis? • What is the abbreviation for the steps in mitosis? • What’s the abbreviation for the steps in meiosis? • Draw a picture showing difference between mitosis & meiosis during metaphase (use 6 chromosomes)

  2. Agenda 2/08 • Sex-linked trait notes • Group practice (w/cards) • Card share-out (bonus points)

  3. Learning Target • I can describe and explain the differences between codominant, incomplete dominant, polygenic, and sex-linked traits

  4. CH 11 Notes #6 Sex-linked Traits

  5. 2 Ways to reproduce • Sexual: sperm and egg make offspring Examples: dogs mating to make puppies, male flower pollinates a female flower **Advantage: shuffles genes to keep populations healthy** • Asexual: one individual clones itself Examples: bacteria divide to reproduce, a new tree grows from a stump

  6. Fish fertilizing eggs Degusia (animal) cloning it’s own head Snakes mating Plant cloning itself

  7. First 22 pairs of chromosomes are called autosomes Sex is determined by the 23rd pair of chromosomes (Called “X” and “Y”) Females: XX Males: XY How do you become a boy or girl?

  8. Question • Does the mother or father determine the sex of the baby? Or both?

  9. The father’s sperm determines sex of the baby He gives an X or Yto the gametes. The mother only gives an X to the gamete

  10. What are the % chances of having a boy or girl? • Chances of having either sex: always 50%

  11. Check for Understanding • A couple are having a baby, what are the chances the baby will be a girl? 50% • A couple have had 3 girls, what are the chances their next child will be a girl? 50% • A couple have had 13 girls. What are their chances their next child will be a girl? 50%

  12. Examples: XrXR XrY Sex-linked genes are genes found on a sex chromosome

  13. Sex-linked Genes • Sex-linked recessive traits will show up more often in males because they only have 1 X chromosome

  14. XR = normal Xr = disease Female Male XRY = Normal XrY = Disease • XRXR = Normal • XRXr = Normal • XrXr = Disease

  15. Carriers • Carrier: A female who has an allele for a genetic disease but does not show the disease. • Carrier genotype: XRXr • Males cannot be carriers because having 1 allele for the disease gives them the disease. • XrY = diseased

  16. Examples of sex-linked traits in humans: 1. Color Blindness 2. Hemophilia 3. Muscular Dystrophy 4. Male pattern baldness 5. Sickle cell anemia

  17. Cannot tell the difference between red and green colors: People with red-green color blindness see either a three or nothing at all. Those with normal color vision see an 8. Colorblindness

  18. A person with normal color vision sees a number seven in the circle above. Those who are color blind usually do not see any number at all. Colorblindness

  19. A female carrier (XNXn) and a man with normal vision (XNY) have kids. What are the chances their kids are colorblind? XN Y Normal vision is dominant (N) Colorblind is recessive (n) Girls _______% Boys_______% XN Xn

  20. Hemophilia- Lacking in the ability to clot blood There is a gene on the “X” chromosome that control blood clotting People who have hemophilia are missing the protein to clot blood They can bleed to death by minor cut. Hemophilia

  21. A female carrier (XHXh) and a man with hemophilia (XhY) have kids. What percentage of their kids have hemophilia? Xh Y Normal clotting is dominant (H) Hemophilia is recessive (h) Girls _______% Boys_______% XH Xh

  22. - Results in weakening/loss of muscles - Caused by defective version of gene that codes for muscle Muscular Dystrophy

  23. Here’s the results • For girls: 0% have the trait • For boys 50% have it. • Percentage is higher for boys because whatever X they get determines the trait, for girls they have to get 2 recessive X’s.

  24. Video • http://www.youtube.com/watch?v=H1HaR47Dqfw

  25. Group practice • Get with other people with card number • Different suits have different jobs • Last 5 min: Randomly calling to give answers! Leader: Keeps the group on task Time Keeper: Keeps track of time, keeps things moving Note Checker: Makes sure all members are using their notes on the problems

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