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Chromosomes

Chromosomes . You have 2 major types of cells: Somatic cells- body cells A sexual Gametes- Germ cells / sex cells such as sperm and egg sexual. Only duplicated in “Synthesis” phase of cell cycle (for mitosis). *Every species has a specific number of chromosomes .

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Chromosomes

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  1. Chromosomes You have 2 major types of cells: Somatic cells- body cells Asexual Gametes- Germ cells/sex cellssuch as sperm and egg sexual

  2. Only duplicated in “Synthesis” phase of cell cycle (for mitosis) *Every species has a specific number of chromosomes. Humans= 46 chromosomes (these come in 23 pairs)

  3. http://www.vivo.colostate.edu/hbooks/genetics/medgen/chromo/species.htmlhttp://www.vivo.colostate.edu/hbooks/genetics/medgen/chromo/species.html

  4. 1) Autosomes= Chromosome pairs #1-22 (related to body appearance; not body sex) 2) Chromosomes come in homologous pairs- (2 chromosomes each: 1 from mom, 1 from dad) *homo= same (same length/size/genes) 3) Sex Chromosomes= Chromosome pair #23 (sex chromosomes, X and Y, determine gender in mammals)

  5. Karyotype- Image of all cell chromosomes #1-22= autosomes #23= Sex chromosomes

  6. XX = Female • XY = Male *Male determines sex of child! Abnormalities in Chromosomes • Autosomeabnormalties: Down syndrome(trisomy 21): The result of an extra copy of chromosome 21. Down syndrome affects 1:800 children

  7. Down syndrome http://www.biology.iupui.edu/biocourses/N100/2K2humancsomaldisorders.html http://www.impactlab.com/wp-content/uploads/2008/10/downschild-255.jpg

  8. Sex Chromosome abnormalties: Klinefelter syndrome: 47, XXYmales. Male sex organs; unusually small testes, sterile. Breast enlargement and other feminine body characteristics. Normal intelligence.

  9. 47, XYY males: Individuals are somewhat taller than average and often have below normal intelligence. At one time (~1970s), it was thought that these men were likely to be criminally aggressive, but this hypothesis has been disproven over time.

  10. Trisomy X: 47, XXX females. 1:1000 live births - healthy and fertile - usually cannot be distinguished from normal female except by karyotype.

  11. Monosomy X (Turner's syndrome): 1:5000 live births; the only viable monosomy in humans - women with Turner's have only 45 chromosomes!!! XO individuals are genetically female, however, they do not mature sexually during puberty and are sterile. Short stature and normal intelligence. (98% of these fetuses die before birth)

  12. Sexual Reproduction- Fission of 2 gametes (= genetic mixture of parents) • Actual fission of egg and sperm = Fertilization • Meiosis- Process of making new sex cells.

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