1. Cell Reproduction Two types of reproduction: Mitosis: Purpose = produces regular body cells for growth and repair Meiosis: Purpose = produces sex cells only http://tbn2.google.com/images?q=tbn:spK6vnBHuv7DlM:http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif

2. Cell Cycle Interphase Mitosis P rophase M etaphase A naphase T elophase Cytokinesis

3. MEIOSIS A different type of cell division! Only occurs for the purpose of producing gametes (= sex cells) Only occurs in reproductive organs (Animals = testes and ovaries)

4. Meiosis Each chromosome begins meiosis by finding its match to make a pair 1 chromosome in each pair comes from the father and 1 from the mother

5. Meiosis A matching pair of chromosomes is called HOMOLOGOUS (= the same) Homologous chromosomes contain genes for the same traits

6. Meiosis v.s. Mitosis Prophase 1 of Meiosis: Homologous chromosomes line up together = TETRAD

7. Meiosis vs. Mitosis Homologous chromosomes are the same size their centromeres are in the same position they have the same number of genes, arranged in the same order.

8. Meiosis v.s. Mitosis Chromosomes swap alleles during Prophase 1. Swapping alleles = crossing over This increases genetic diversity  NO two people are exactly alike

9. Meiosis v.s. Mitosis Meiosis - Number of Daughter Cells = FOUR Mitosis – Number of Daughter Cells = TWO

10. Meiosis v.s. Mitosis In meiosis each daughter cell has HALF the number of chromosomes as the parent cell. In mitosis each daughter cell has the SAME number of chromosomes as the parent cell.

11. Meiosis, What’s the big deal? Meiosis is the reason that in sexually reproducing organisms genetic information varies between parent and offspring, Genetic information varies between offspring from the same parents.

12. Ensures genetic variation, which is essential for evolution. The genes/traits of a species change from generation to generation. Meiosis

13. MEIOSIS: to make sex cells with half the original DNA. Parent cell 4 daughter cells with half of DNA from parent cell

14. Mitosis vs. Meiosis Parent cell 2 daughter cells with identical DNA to parent cell 4 daughter cells with half of DNA from parent cell Parent cell 4 gametes

15. Vocabulary for Bio Somatic cell: a body cell that has the organisms complete diploid set of chromosomes. Diploid = a cell that contains both sets of homologous chromosomes from the parent. Gamete: sex cell, sperm or egg cell containing the haploid set of chromosomes Haploid = a cell containing 1 set of genes

16. In Humans 46 chromosomes in somatic (body) cells 23 chromosomes in sperm cells and egg cells (gametes). During fertilization a sperm fertilizes an egg producing a zygote with 46 chromosomes. Through the process of MITOSIS the zygote grows and develops into a human baby. http://www.miscarriage.com.au/images/pages/karyotype_normal.jpg

17. AND FINALLY Mitosis: results in two daughter cells with identical chromosomes and the exact same number of chromosomes as the parent cell. Meiosis: results in four cells with different chromosomes and half the number of chromosomes as the parent cell*.parent cell*.