1. The Cell Cycle Mitosis and Meiosis Cancer

2. Why do cells reproduce??  Cell theory Pt. II  Agar Lab  Repair and Growth  GrowthQuest  Reproduction

3. Reproduction  Asexual reproduction  All genetic material inherited from one parent  No sperm or egg cells produced  Sexual reproduction  Sperm and egg cells unite in fertilization  All multicellular organisms depend on cell division for growth.

4. Cell Cycle  Key Terms- look in your book!:  Chromosomes  Chromatin  Sister chromatids  centromere

5. The Cell Cycle:

6. Interphase  As much as 90% of the cell cycle spent in interphase  Carries out metabolic processes and performs its functions  G 1 phase (Gap 1)  S phase (DNA synthesis)  G 2 phase (Gap 2)  Online Activity 9.2

7. Mitosis  Nucleus and duplicated chromosomes are evenly distributed, forming two “daughter” nuclei  Cytokinesis  Occurs simultaneously with telophase  NOT part of mitosis, which is division of nucleus  Four stages of mitosis  Prophase  Metaphase  Anaphase  Telophase

8. Prophase  What has happened leading up to prophase?  What happens to the cell during prophase?

10. Metaphase  Where do the chromosomes go during metaphase?  Mitotic spindle

12. Anaphase  Sister chromatids  Chromatids become chromosomes  Now chromosomes, they separate at centromere and move to poles

14. Telophase  Final stage- when does it begin?  Chromosomes  Chromatin  Nucleoli  Cytokinesis –cytoplasmic division!  Contrast animals and plants

16. Cancer cells  Online Activity 9.4  “Causes” –  Chance mutations  Carcinogens  Inherited  Benign vs. malignant tumors  Metastasis  Cancer treatments  Side effects?

17. Genes and Cancer  All kinds of cancer occur when cell division, normally a very highly regulated process, gets out of control.  While environmental factors can certainly contribute to a person's risk of cancer (e.g. smoking, diet, and exercise), most cancers have a genetic basis too.  Literally hundreds of genes and proteins are involved in monitoring the process of cell division and DNA replication;  a mutation in one or more of these genes or proteins can sometimes lead to uncontrolled cancerous growth.  From: Genes and Disease  http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=gnd.section.102&ref=sidebar http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=gnd.section.102&ref=sidebar

18. Meiosis  What is it?  Terms:  Karyotype  Homologous chromosomes (different from sister chromatids!)  Sex chromosomes  What is reduction division?

19. More terms…  Diploid vs. haploid cells  How many chromosomes to most human cells (somatic cells = body cells) have?  How many do sex cells (gametes) have?  Why must gametes have ½ the chromosomes found in somatic cells?  Gametes, fertilization, and zygotes

20. Karyotypes What is a karyotype? How are karyotypes obtained? Why would someone have a karyotype done on their cells?

21. Meiosis vs. Mitosis  1) four new cells with one set of chromosomes vs. two cells with two sets of chromosomes  2) exchange of genetic material between homologous chromosomes vs. no exchange

22. Meiosis I

23. Meiosis II

24. Genetic variation  Why do you look different from your parents?  Independent Assortment Independent Assortment Independent Assortment  Non-homologous chromosomes assort independent of any other pair of chromosomes during meiosis  There are about 8 million possible chromosome combinations!  What is crossing over?  Genetic recombination