1. Where Do Cells Come From? “All cells come from pre-existing cells” -Cell Theory 3 types of cell divisions: Mitosis-nuclear cell division in somatic cells, asexual reproduction Meiosis-nuclear cell division in germ cells, sexual reproduction Prokaryotic Fission-cell division in bacteria cells, asexual reproduction

2. Review of Terms used in Mitosis/Meiosis Somatic cells-all cells except sex cells Germ cells-sex cells, sperm and eggs Diploid-2 of every chromosome Haploid-1 of each chromosome Chromosome-a linear arrangement of genes, composed of DNA How many chromosomes are found in humans? Which cells are diploid and haploid in humans?

3. Review of Terms used in Mitosis/Meiosis Chromatid-1 arm of duplicated chromosome, sister chromatids Centromere-area on chromosome that holds chromatids together Histones-proteins associated with chromosomes, organize structure Nucleosome-1 unit of DNA + 8 histones Chromatin-all DNA + histones + other proteins

4. Eukaryotic Cell Cycle Interphase-3 phases G1-initial growth, G0  resting phase, permanently arrested S-synthesis, DNA is duplicated G2-final preparations before mitosis, microtubule formation Mitosis-4 phases: Prophase, Metaphase, Anaphase, Telophase Cytokinesis-division of cytoplasm Most adult cells are in what phase of the cell cycle?

5. Control of the Cell Cycle Tightly regulated, require signals Cyclins required for cells to move from G1  S, G2  M In mammalian cells p53 stops cycle if DNA is damaged, hasn’t finished replicating, or if chromosomes are not attached to spindle High levels result in apoptosis  programmed cell death through caspases

6. Mitosis Produces 2 identical diploid daughter cells from 1 parent cell Have the same DNA  clones Used for growth and repair Asexual reproduction used by some members of fungi, plants, animals, protists

7. Mitosis-PMAT Prophase Chromosomes condense Nucleolus disappears, nuclear envelope breaks apart Centrioles duplicate, move to opposite poles Microtubules grab chromosomes in order to move them Longest phase

8. Mitosis-PMAT Metaphase- microtubules align chromosomes at the equator of a cell, “metaphase plate” Kinetochore spindle fibers attached to sister chromatids come from poles

9. Mitosis-PMAT Anaphase-pulling apart of chromatids/centromeres, microtubules contract, moving chromatids to opposite poles, “spindle apparatus” is clearly visible Shortest phase Telophase-chromosomes decondense, nuclear envelope reforms, nucleolus reappears

10. Cytokinesis Division of cytoplasm Occurring simultaneously with telophase Occurs differently in plant and animal cells Cell plate formation- Plant cells Vesicles from golgi align at equator and fuse to form cell wall Cleavage Furrowing- Animal Cells Actin filaments align at equator (contratile ring)and contract until separate cell into two

11. Stem Cells and Cloning Stem cells  adult cells that retain ability to divide Can differentiate into different types of cells Therapeutic cloning  produces human tissues Reproductive cloning  new individual can be made

12. Cloning and Embryonic Stem Cells Embryonic Stem Cells (ES)-cells from an early embryo; these cells have not received the genetic instructions to become a specialized cell yet These cells can be transferred into a organ and become that type of tissue. Example: ES cells  defective pancreas, become pancreas cells and start producing insulin

13. Stem Cell Lines 100s have already been created that are heart, liver, pancreas, etc. cell lines Eventually, transplant into humans; mice studies are very promising Problems: immune reaction Getting the cells to defective tissue Ethical issues (no fertilized egg required)

14. Properties of Cancer Cells: loss of cell cycle control (When Compared to Normal Cells) Additional chromosomes, genes Grow and divide abnormally (faster) Less adhesive, don’t stick to each other Metastasize-migrate to other locations Don’t communicate with each other Don’t apoptose (die)

15. Cancer Unregulated and uncontrolled cellular growth Form tumors Metastasize

16. Cancer: Loss of Genetic Controls over Cells Cell growth and repair is tightly regulated by genes; when these genes fail  Cancer Proto-oncogene (accelerator) normal growth gene becomes mutated  oncogene, BRCA1 Tumor suppressor genes (brakes) -control cell death, ex. p53 gene

17. Causes of Cancer UV, X-ray, gamma radiation, chemicals in work places, smoking Viruses  Hepatitis C,  liver cancer, HPV  genital warts  cervical cancer Chromosome translocation  leukemia Carcinogens-cancer causing agents, ex. Compounds found in cigarettes

18. Cancer : Tumors and Treatment Benign-slow growth, no metastasis, not lethal unless size becomes large Malignant-rapid growth, metastasize, destroy tissue around them Treatment Chemotherapy-targets quickly dividing cells, both cancer and healthy Radiation Therapy-high energy radiation targets only tumor

19. Prokaryotic Cell Division Binary fission Asexual reproduction No nucleus, only nucleoid region Single circular chromosome Cell wall