2. Cell grows Interphase DNA copied G1G1 S – Cell is doing its job

3. DNA 46 strands in each human body cell Each strand has many sections called genes. Each genes codes for a protein. The DNA is in the shape of a double helix

4. DNA can either be spread out (chromatin) …or condensed (chromosome)

5. DNA = Deoxyribonucleic Acid Deoxyribose sugar Nitrogen Bases: Adenine - A Thymine - T Cytosine - C Guanine - G Phosphate group

6. S---p---S---p---S---p---S---p---S---p p---S---p---S---p---S---p---S---p---S A C T G C TGGAC

7. S---p---S---p---S---p---S---p---S---p p---S---p---S A C T G C TG G A C p---S

8. S---p---S---p---S---p---S---p---S---p p---S---p---S---p---S---p---S---p---S A C T G C T G GA C

9. S---p---S---p---S---p---S---p---S---p p---S---p---S---p---S---p---S---p---S A C T G C T G G AC p---S---p---S---p---S---p---S---p---S TGGAC S---p---S---p---S---p---S---p---S---p A C T G C Centromere

10. chromatid centromere …..OR….. TWO identical copies of DNA that are attached Chromosomes can exist as ONE copy of DNA

11. Cell Division Cytoplasm (cell) is divided Cell grows Interphase DNA copied Makes organelles G1G1 G2G2 S – Cell is doing its job Nucleus is divided (copied) Mitosis Cytokinesis Process of dividing one “parent cell” into two “daughter cells”

12. Single celled organisms : 1)Allows these organisms to reproduce asexually. 2)Single celled organisms are able to grow in population.

13. Multicellular organisms : Allows these organisms to grow in size and maintain surface are to volume ratio. Allow for specialization through cell differentiation. Cells that are dead and damaged can be replaced.

14. Division of the nucleus. Continues throughout life as a body grows and repairs or replaces worn-out cells. Mitosis consists of 4 stages: 1) Prophase 2) Metaphase 3) Anaphase 4) Telophase Creates two identical Nuclei

15. - NOT a part of mitosis - Division of the cytoplasm -Results in two identical daughter cells, each with exact copies of the parent cell’s genetic material

16. What are the steps in mitosis? Goal: – Explain what happens in each step in mitosis Prophase Metaphase Anapahase Telophase

17. 1. Prophase - Chromosomes begin to condense and become visible (present as two sister chromatids joined at the centromere) - Nuclear membrane breaks down - Chromosomes are scattered throughout cytoplasm - Spindle fibers form between centrioles & each centromere - Nucleolus disappears

19. chromosomes are moved by spindle fibers attached at the centromere - Chromosomes line up on the mid-line of the cell (called the Metaphase plate) (The chromatids will split apart at their centromeres, giving rise to two identical daughter chromosomes.) 2. metaphase

21. - Sister chromatids separate at their centromeres = each chromatid is now a chromosome - Chromosomes move to opposite ends of the cell (there is now a complete set of chromosomes at each end) 3. Anaphase

23. - Chromosomes uncoil into chromatin. - New nuclear membrane forms around BOTH groups of chromosomes – nucleoli reform in each nucleus. - Spindle fibers disappear. (Cell pinches in middle to begin formation of two cells.) 4. Telophase

26.  Cytokinesis: Division of the Cytoplasm  Cytokinesis divides structures within the cytoplasm (ribosmes, Golgi apparatus, mitochondria, etc.)  Sometimes starts as telophase finishes -Results in two identical daughter cells, each with exact copies of the parent cell’s genetic material

27.  In animal cells - cleavage furrow forms at the metaphase plate to pinch cytoplasm in two.

28.  In plant cells, cell plate is formed during cytokinesis cell plate eventually becomes cell wall

31. What controls the Cell Cycle? 1) Environmental Factors : pH, nutrients, temperature, etc. 2) Density of cells : density-dependent inhibition—cell will not divide if it is crowded, must also be attached to a surface to divide

32. Cancer - uncontrolled division of cells. 1)Cells do not respond to normal cell division controls. 2)Cells divide indefinitely without aging and dying.

33.  Transformation - normal cell is converted to a cancer cell.  If the immune system does not destroy this cancer cell it divides to form a tumor  Tumor is benign if it remains in the same place. A malignant tumor has the ability to spread.  Metastasis - cancer cells enter the circulatory system and spread to all parts of the body.