1. Meiosis

2. What is Meiosis???
the process of nuclear division in sexual reproduction where the number of the chromosomes is halved.
produces four daughter cells
all daughter cells are haploid (half the set)
chromosomes are shuffled in the process, so that each daughter cell has a unique combination
used to create gametes (sperm and egg)

3. Total # of Cells at the End
Mitosis vs. Meiosis
# of Divisions 1 2
Type of Reproduction
Asexual
Sexual
Cells Produced
Body Cells
Sex cells
Total # of Cells at the End
2 identical
Diploid (2n) cells
4 not identical
Haploid (n) cells

4. Total # of Chromosomes in the End
Mitosis vs. Meiosis
Total # of Chromosomes in the End 46 23
Crossing Over No
Yes
Number of Steps
4- PMAT
8- PMAT I
PMAT II

5. A COMPARISON OF SEXUAL VERSUS ASEXUAL REPRODUCTION
Sexual Asexual

6. Sexual Reproduction
Involves the fusion of gametes (Egg and Sperm)
COMBINES GENES FROM TWO DIFFERENT PARENTS TO FORGENETICALLY DIVERSE OFFSPRING.

7. 8-Phases of Meiosis
1.Prophase- Each Chromosome pairs up 2. Metaphase- Line up in the middle 3. Anaphase- Chromosomes pull apart. 4. Telephase- Cell separates in 2 cells

8. 8 Phases of Meiosis
5. Prophase II- Chromosomes pair again in the 2 haploid cells.
6. Metaphase II- Line up in the middle
7. Anaphase II- Chromosomes pull apart
8. Telephase/Cytokinesis- Result in 4 haploid (N) daughter cells.

10. Unique in Meiosis
Crossing Over- homologous chromosomes exchange portions of their chromatids resulting in the exchange of alleles, producing NEW COMBINATIONS!!

11. Unique in Meiosis
Independent Assortment- In addition to Crossing-Over, the process of meiosis ensures that chromosomes are randomly assorted.
The following images show three separate possibility for a single cell that has undergone meiosis. Look at all the different combinations

12. Fun Fact
THE 23RD PAIR, THE SEX CHROMOSOMESDETERMINES WHETHER THE PERSON IS FEMALE (XX) OR MALE (XY)