Presentation explaining the process of meiosis in cells.

1. Meiosis

2. - Mosquito is used in this
presentation because it has 3 pairs
of chromosomes (less drawing!)
- Humans have 22 pairs of
chromosomes and one pair of sex
chromosomes
- One set is from the mom, one set
from the dad
This is a human karyotype. A
karyotype lays out all the
chromosomes in an organism from
longest to shortest in length (numerical
order). Shows all the chromosomes
and the sex chromosomes from the
mom and the dad. This karyotype is
from a male because it has both X and
Y chromosomes.

3. Pre: Interphase
Chromosomes
replicate
themselves
Sister chromatids
are created
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4. Prophase 1
Homologous
chromosome pairs pair
up together
Crossing over
Crossing over- when
homologous chromosome
pairs switch their DNA
*Crossing over
sometimes occurs
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5. Metaphase 1
Homologous
chromosomes
separate
Randomly line up
in the middle to be
separated
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6. Anaphase 1
Spindle fibers
attach to
centromeres and
pull the
chromosomes
apart
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7. Telophase 1
Cells split into
two daughter cells
Cytokinesis
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8. Prophase II
Centrioles move
into position
Nuclear
membranes break
down
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9. Metaphase II
Chromosomes
line up in the
middle to separate
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10. Anaphase II
Spindle fibers
attach to sister
chromatids
Chromatids
pulled apart
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11. Telophase II
Cells separate
to create 4
haploid
cells/gametes
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12. Essential Points
Meiosis is used to produce cells for genetic reproduction
Occurs in germ/sex cells
Diploid--> Haploid cells
3 ways variation increases:
Homologous chromosomes pair cross-over
(Prophase 1)
Independent (random) assortment of maternal and
paternal chromosomes (how they line up, Metaphase I)
Fertilization between random sperm and egg
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