Meiosis is a cell division process that produces gametes, or sex cells, which have half the number of chromosomes as the parent cell. It involves two nuclear divisions and results in four daughter cells with only one half of the original number of chromosomes. This ensures each gamete has a unique combination of chromosomes and allows for genetic variation in offspring from sexual reproduction.

1. Presenting…
Meiosis

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Why is meiosis important?
• It makes sexual reproduction possible. P.324
• Results in a new individual that has a unique
combination of genes.Pg. 613
• Each parent gives exactly one-half of the chromosomes.
• Making a full set of chromosomes for its species.

3. Meiosis
i = how i was created!
• Two nuclear divisions
• Produce or make:
1. Sex cells (sperm and
egg)
2. The sex cells have half
of the chromosomes of
the parent cell -23
3. This happens to make
cells for sexual
reproduction (Oh my!)

4. • Sex Cell
• Egg or sperm
• Sex Chromosome
• Thread-like
chromosome that
carries the genes
that determine the
sex of the offspring.
• XX=girl
• XY=boy

5. Meiosis Animation
• http://www.biology.arizona.edu/cell_bio/tut
orials/meiosis/page3.html

6. Comparison
Mitosis and Meiosis
• Mitosis
• Meiosis
• (My toe, sis!)
• Makes body cells.
• New cells have the same
number of
chromosomes as the
original cell. IDENTICAL
• (i was made this way!!)
• Makes sex cells.
• New cells have half of
the number of
chromosomes as the
original.
• New cells are identical
to the original cell
• No two sperm or egg
cells are ever exactly
alike.
•
Meaning:
Skin cells make skin cells,
bone cells make bone cells,
etc.
• Offspring or babies will be
unique!