1. Marcellin Biology Notes
Meiosis

2. Why do we look like our parents?
Because we are a combination of their genetic information.

3. Chromosome Number Humans have 46 chromosomes.
How do we get this number?
In sexual reproduction:
Mom donates 23 chromosomes.
Dad donates 23 chromosomes.
Total = 46 chromosomes

4. Karyotype- Chromosome Diagram

5. Meiosis The process which reduces the number of chromosomes by half.
Also known as gamete formation.
Produces haploid cells
Sperm cells and egg cells (gametes) are haploid cells.

7. Stages of Meiosis: Meiosis I
Interphase I
Chromosomes copy right before meiosis begins.
Prophase I
Nuclear membrane dissolves.
Sister chromatids form.
Similar chromosomes pair up forming homologous pairs.

8. Stages of Meiosis: Meiosis I
Metaphase I
Homologous pairs line up in the middle of the cell.
Anaphase I
The homologous pairs separate and move to the poles.

9. Stages of Meiosis: Meiosis I
Telophase I
Cell divides into 2 daughter cells.

10. Stages of Meiosis: Meiosis II
Prophase II
Chromosomes are NOT copied again.
Metaphase II
The sister chromatids line up at the center of the cell.

11. Stages of Meiosis: Meiosis II
Anaphase II
Sister chromatids are separated and move to the poles.
Telophase II
Four new nuclei form in each cell.
Cytokinesis takes place.