http://www.youtube.com/watch?v=mKWxeMMFTEU- 11 minutes process with music

Mitosis- Cell division• 46 chromo2 cells, 46 chromo. Each• Keeps chromo. # same• Found in body cells• Most common• No genetic variation

Meiosis- Cell division• 46 chromo 4 cells, 23 chromo each• Chromo. # cut in half• Found in sex/germ cells

ONLY• Least common• Most genetic variation

ANIMATION OF COMPARISON

ANIMATION 2 OF COMPARISON

Meiosis• Definition: cell division to produce egg (ovule) or sperm (pollen)

Meiosis I & Meiosis II

Karyotypes• Display of chromosomes

lined up in homologous pairs

• Half inherited from male Half from female

• Used for viewing #, size, shape, and banding patterns of chromosomes

Homologous Chromosomes:matching pair of chromosomes, one

inherited from each parent

“Diploid”or 2N: having two sets of chromosomes, body cells

Humans 46 chromosomes

“Haploid”or N: having one set of chromosomes, sex cells ( gametes)

Humans 23 chromosomes

Diploid vs. Haploid Exercises

• Drosophilia have a diploid number of 8. What is the haploid?

• Onions have a haploid number of 8. What is the 2N?

• A horse’s 2N is 64. What is the 1N?• A body cell of an alligator has 32

chromosomes. Is this the diploid or haploid number?

4

16

32

Diploid

• Fertilization: when haploid sperm and egg meet, combining N

chromosomes with N chromosomes = 2N zygote

• Zygote: fertilized egg, 2N

____ ____ ____

Oogenesis: Production of Egg

• Female meiosis in the ovaries

• Resulting cells: 1 egg, 3 polar bodies• Haploid

Spermatogenesis:Production of Sperm

• Male meiosis in testes

• Resulting cells: 4 haploid sperm

cells

INDEPENDENT ASSORTMENT

CELL THEN GOES THROUGH cytokinesis ”- NO INTERPHASE NO MORE DOUBLING OF CHROMOSOMES!!

General Process of Meiosis

• MEIOSIS II (PMAT II & C)- Starts with 2 haploid cells- Prophase, Metaphase, Anaphase, Telophase IIand Cytokinesis serve to separate the sisterchromatids- Ending Cells: 4 cells, each with haploid chromosomes

Meiosis II

Another Animation of Overall Meiosis

McGraw Hill Animation

• http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120074/bio17.swf::Comparison%20of%20Meiosis%20and%20Mitosis