Meiosis: Creation of Meiosis: Creation of the Sex Cellsthe Sex Cells
What What is is Meiosis??Meiosis?? MeiosisMeiosis- creation of sex cells (eggs, - creation of sex cells (eggs,
sperm)sperm) Occurs in testes in males, ovaries in Occurs in testes in males, ovaries in
femalesfemales At the end, 4 cells are created that At the end, 4 cells are created that
are NOT identical to the starting cell. are NOT identical to the starting cell.
Karyotypes Karyotypes Display of the 46 chromosomes of an Display of the 46 chromosomes of an
individualindividual 23 23 homologous pairshomologous pairs of of
chromosomeschromosomes
Female Male
Homologous ChromosomesHomologous Chromosomes Two chromosomes of each matching Two chromosomes of each matching
pairpair– 1 from mom & 1 from dad1 from mom & 1 from dad
Diploid/ HaploidDiploid/ Haploid Diploid (2n)-Diploid (2n)- cells with 2 homologous cells with 2 homologous
sets of chromosomes (2n= 46 in sets of chromosomes (2n= 46 in humans)humans)
Haploid (n)-Haploid (n)- Single set of Single set of chromosomes (n= 23 in humans)chromosomes (n= 23 in humans)– Sex cells produced through meiosisSex cells produced through meiosis
Human Life CycleHuman Life Cycle
Mitosis vs. MeiosisMitosis vs. Meiosis MITOSISMITOSIS MEIOSISMEIOSIS
– Body cellsBody cells - Gametes- Gametes– Produces 2 identicalProduces 2 identical - Produces 4 - Produces 4
different cells (diploid)different cells (diploid) cells cells (haploid) (haploid)
MeiosisMeiosis 2 parts- Meiosis I and Meiosis II2 parts- Meiosis I and Meiosis II
VideoVideo MeiosisMeiosis
Crossing OverCrossing Over Human offspring are genetically Human offspring are genetically
different from their parents…different from their parents… WHY??WHY?? Occurs during Occurs during Prophase IProphase I Homologous chromosomes exchange Homologous chromosomes exchange
some genetic materialsome genetic material Why is this important??Why is this important??
– Allows for more variation in the cells. Allows for more variation in the cells.
Crossing OverCrossing Over
Mitosis vs. MeiosisMitosis vs. Meiosis
Mitosis vs. MeiosisMitosis vs. Meiosis Describe two differences between Describe two differences between
meiosis and mitosis.meiosis and mitosis.– 1) 1) – 2) 2)
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