1. Meiosis
Science 9

2. Chromosomes How many chromosomes do we have? How many come from mom?
How many come from dad?

3. Chromosomes The 46 human chromosomes can be broken down into 23 pairs
One half of each pair comes from your mother and the other half comes from your father
Homologous pairs:
A pair of chromosomes containing a maternal and paternal chromatid joined together at the centromere

4. Chromosomes Diploids Haploids
A cell containing two complete sets of chromosomes
Haploids
Have a single set of unpaired chromosomes

5. Chromosomes
Gametes
Male or female haploid cell that is able to unite with another of the opposite sex in sexual reproduction to form a diploid zygote

6. Meiosis What does mitosis do? Meiosis:
Cell growth maintaining number of chromosomes
Meiosis:
The process that ensures each gamete contains only one-half set of chromosomes
Ensures each gamete has a different combination of the chromosomes that were present before meiosis

7. Stages of Meiosis Prophase 1 Crossing-over:
Each Chromosome duplicates and remains closely associated. These are called sister chromatids. Crossing-over can occur during the latter part of this stage.
Crossing-over:
The exchange of genetic information between homologous pairs

8. Stages of Meiosis

9. Stages of Meiosis Metaphase 1:
Homologous chromosomes align at the equatorial plate.

10. Stages of Meiosis Anaphase 1
Homologous pairs separate with sister chromatids remaining together

11. Stages of Meiosis Telophase 1
Two daughter cells are formed with each daughter containing only one chromosome of the homologous pair.

12. Stages of Meiosis
Prophase 2:
DNA does not replicate

13. Stages of Meiosis Metaphase 2:
Chromosomes align at the equatorial plate.

14. Stages of Meiosis Anaphase 2:
Centromeres divide and sister chromatids migrate separately to each pole.

15. Stages of Meiosis Telophase 2:
Cell division is complete. Four haploid daughter cells are obtained.

16. Formation of Gametes Gametes are produced in the reproductive organs
Male gametes, called sperm, are produced in testes
Female gametes, called eggs, are produced in ovaries

17. Formation of Gametes

18. Formation of Gametes

19. Meiosis
Video- Crash Course Meiosis