1. Making gametes; the sexiest of the cells
Objective: describe the process of meiosis and compare the processes of meiosis and mitosis

2. Different organisms have different numbers of chromosomes
Scientists use the letter n to represent the number of chromosomes each organism has
Human n= 23
Dog n= 39; Daisy n= 9
Leopard Gecko n= 19

3. Diploid Definition
A cell with a complete set of chromosomes is called a diploid cell.
Represented by
2n to show a complete set of chromosomes

4. Haploid Definition
Cells that carry only half the genetic material of the parent are referred to as haploid cells.
Represented By
n to show half the diploid number

5. Sexual Reproduction

6. Sexual Reproduction Requires 2 sex cells (sperm and egg)
Also called gametes
Unite to form diploid cells

7. Meiosis Sex cells are produced by a process called meiosis
2 Stages: Meiosis I and Meiosis II
Makes 4 new cells, each with half the DNA of the parent cells

8. Stages of Meiosis
Meiosis I

9. Interphase Same as mitosis DNA in chromatin
Centrioles
DNA
Nuclear Membrane
Same as mitosis
DNA in chromatin
Cells are growing and doing their normal cell jobs
DNA= 2n

10. Prophase I
DNA condenses into chromosomes and homologous chromosomes pair (homologous= carry same genes)
These chromosome pairs are called tetrads
Crossing over occurs in this step

11. Crossing Over
Parts of homologous chromosomes are exchanged

12. Metaphase I Like metaphase in mitosis
Chromosomes like up in the center of the cell
Nuclear membrane now gone

13. Anaphase I
Homologous chromosomes are pulled to the opposite ends of the cell
Reduction step- each side only getting half of DNA

14. Telophase I and Cytokinesis
Nuclear membrane reforms
Cytoplasm is divided between the two cells
DNA= n