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Warm Up- 11/6

Learn about meiosis, a two-part cell division process that creates gametes and results in four haploid cells. Discover the differences between meiosis and mitosis, and explore the topics of crossing over and nondisjunction. Also, explore genetic disorders such as Down's syndrome, Turner's syndrome, Kleinfelter's syndrome, and Patau's syndrome.

richardkeenan
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Warm Up- 11/6

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  1. Warm Up- 11/6 • Who do you receive more genes from: Mom or Dad?

  2. Good Things

  3. Announcements • Test Corrections- Advocate or After School this week only! • Extra Credit- Tissues

  4. Warm Up- 11/7 What biomolecule made of carbon, hydrogen, and oxygen is used to make energy (ATP)?

  5. Good Things

  6. Notes: Meiosis

  7. Meiosis I 92 46

  8. Meiosis II between What does Inter mean???

  9. Meiosis II

  10. equator Meiosis II NOW … single file line

  11. Meiosis II

  12. Meiosis II 46 23 4 haploid cells

  13. Meiosis I Meiosis II Meiosis – one more time Meiosis is a two-part cell division process….

  14. Meiosis II – one more time … which results in 4 gametes with one half the number of chromosomes of the parent cell. 4 haploid cells 4 haploid cells

  15. Mitosis vs. MEIOSIS mitosis meiosis • Takes place to create gametes • Creates 4 cells • Creates haploid cells • Daughter cells are NOT identical to parent cells • Used in SEXUAL reproduction • 2 divisions • Homologous chromosomes line up in a single file line in metaphase II • Takes place to create somatic cells • Creates 2 cells • Creates diploid cells • Daughter cells are identical to parent cell • Used in ASEXUAL reproduction • 1 division • Homologous chromosomes line up in a single file line in metaphase • Chromosomes duplicate in Interphase • Both a type of cell division • Both required to sustain life http://www.pbs.org/wgbh/nova/miracle/divi_flash.html

  16. Meiosis creates • 4 haploid cells • Spermatogenesis (meiosis of sperms cells) takes about 64 days. All 4 sperm will survive. • Oogenesis (meiosis of egg cells) is complete when a female is born. Only 1 egg of the 4 will become viable.

  17. Warm Up- 11/8 • What process happens in the mitochondria and what does it produce?

  18. Good Things

  19. Finish Notes…

  20. Crossing Over • To make things more interesting, crossing over can occur during Prophase I. • During metaphase I, the homologous chromosomes line up together and form tetrads. Remember??

  21. Crossing Over • Crossing over takes place when two chromosomes, break and then reconnect but to the different end piece. • Crossing over increases the number of variations that can exist in offspring.

  22. Crossing Over • Which of the following did crossing over ONLY take place? B A C

  23. Nondisjunction • Although the events of meiosis usually proceed accurately, sometimes an accident occurs and the chromosomes fail to separate correctly. This is known as nondisjunction.

  24. Nondisjunction • The zygote that has been created will have an extra or missing chromosome. This would result in an inherited genetic disorder. • In most cases, the presence of an additional chromosome or missing chromosome results in the death of the zygote.

  25. Nondisjunction • The zygote that has been created will have and diploid number of chromosomes plus the extra chromosomen+1 = 47 chromosomes. Monosomy - the presence of only one chromosome from a pair in a cell's nucleus. Trisomy – the presence of three chromosomes instead of 2 in a cell’s nucleus.

  26. Karyotypes • When you are born, doctors take a sample of your blood and create a karyotype. This will enable the doctor to see if you have any additional or missing chromosomes. • A karyotype is a standardized arrangement of all the chromosomes of a cell.

  27. Karyotypes Homologous chromosomes are paired up, then they are put in order from the LARGEST chromosome pair to the smallest.

  28. Karyotypes 2 x chromosomes = GIRL autosomes sex chromosomes

  29. Karyotypes Everything okay here?? What gender?? 2 different sized sex chromosomes = male

  30. Everything okay here?? Down’s syndrome trisomy 21 • decreased muscle tone at birth • asymmetrical or odd-shaped skull • round head with flat area at the back of the head • slanting eyes • small mouth with protruding tongue • single crease on the palm • slowed growth and development • delayed mental and social skills trisomy 21 trisomy 21

  31. Warm Up- 11/9 • Draw a phospholipid and label the HYDROPHILIC and HYDROPHOBIC ends.

  32. Good Things

  33. Disorders • Down’s • Kleinfelters • Turner’s • Patau’s

  34. Everything okay here?? Turner’s syndrome • short stature (affects almost all girls with Turner, to different degrees) • failure of ovaries to develop (90-95% of girls) • webbed neck (25%) or short neck (40%) • abnormal fingernails and toenails (70%) • hearing disorders (50-90%) • frequent ear infections in childhood (75%) monosomy X monosomy X monosomy X

  35. Turner’s syndrome XO XO XO XO

  36. Everything okay here?? Kleinfelter’s syndrome XXY XXY XXY

  37. Kleinfelter’s syndrome • No symptoms - some men are unaware they have an extra chromosome • Enlarged male breasts - only severe in about 10% of cases • Sparse facial hair • Sparse body hair • Inability to produce sperm • Tallness - more likely to be taller than non-XXY males. • Thinness • Normal intelligence • Language impairment • Delayed language XXY XXY

  38. Kleinfelter’s syndrome XXY XXY XXY XXY

  39. Everything okay here?? Patau’s syndrome trisomy 13 trisomy 13 trisomy 13 trisomy 13

  40. Patau’s Syndrome • Mental retardation, severe • Seizures • Small head • Scalp defects (absent skin) • Small eyes (microphthalmia) • Cleft lip and/or palate

  41. Worksheet

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