1. Cell Reproduction http://tbn2.google.com/images?q=tbn:spK6vnBHuv7DlM:http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif

2. Cell Cycle Interphase and Mitosis

3. DNA replication For most of a cells life chromosome is a single copy of DNA looking like But during the “s” phase of interphase the chromosome copies itself making sister chromatids joined in the middle by a centromere ChromatidSister Chromatids

4. Mitosis When a cell goes through the phases Prophase Metaphase Anaphase Telophase to make two “daughter” cells that are exactly identical to the original “parent” cell

5. http://www.pbs.org/wgbh/nova/miracle/divi_text_03.html Interphase prophase metaphase anaphase telophase 2 daughter cells in Interphase Mitosis: cell reproduction to make exact copies of cells

6. 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; Plants = stamen and ovaries)

7. Meiosis v.s. Mitosis Chromosomes (pair of sister chromatids) line up in homologous pairs (instead of singly) during prophase = TETRAD

8. Homologous Chromosomes Organisms have pairs of chromosomes with corresponding DNA sequences one from each parent. 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.

9. Homologous chromosomes Karyotype = photograph of all of the human homologous chromosomes Note: each chromosome is single without its sister chromatid

10. Meiosis vs. Mitosis During Prophase 1 of meiosis, the chromosomes in the tetrads swap alleles Swapping alleles = crossing over

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. Meiosis ensures genetic variation which is essential for evolution. Species genes/traits change from generation to generation. With a GREAT deal of time this can produce significant changes Meiosis

13. Meiosis: process to make sex cells Daughter cells made from Meiosis are NOT identical to the “parent” cell. Regular human body cell = 46 chromosomes (somatic cell = diploid cell = 2N) Human sperm and egg = 23 chromosomes (sex cells or gametes = haploid cell = N) Also crossing over happens where pieces of the original chromosomes exchange places.

14. Products of Meiosis Daughter cells have half the DNA of the parent cell The chromosomes in each of the 4 daughter cells are different as a result of crossing over. 4 daughter cells Parent cell

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

16. 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 2 diploid somatic cells4 haploid gametes

17. Mitosis vs. Meiosis Mitosis: results in two cells with identical chromosomes Meiosis: results in four cells with different chromosomes* chromosomes

18. http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/animation__comparison_of_meio sis_and_mitosis__quiz_1_.html animation comparing meiosis and mitosis http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/animation__comparison_of_meio sis_and_mitosis__quiz_1_.html http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/difficult_multiple_choice.html questions starting at 15 http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter2/difficult_multiple_choice.html http://www.sciencegeek.net/Biology/review/U3Review.htm 30 question quiz http://www.sciencegeek.net/Biology/review/U3Review.htm http://www.biologycorner.com/quiz/qz_meiosis.html 3 question quiz http://www.biologycorner.com/quiz/qz_meiosis.html