Chromosomes Binary Fission Mitosis Cancer

1. Cell division ChromosomesBinary FissionMitosisCancer

2. CHROMOSOMES

3. CHROMOSOMES • Are Tightly coiled strands of DNA and chromatin • located in the nucleus of each cell • control growth and development

4. CHROMOSOMES Section 8.2 Summary – pages 201 - 210 • Become darkly colored when stained. • Are the carriers of the genetic material that is copied and passed from generation to generation of cells. • Accurate transmission of chromosomes during cell division is critical.

5. CHROMOSOMES Human Chromosome Number 1. 46 total chromosomes 2. Diploid cells = contain all 46 (full set) 3. Haploid cells = contain 23 (half set)

6. CHROMOSOMES Two types of chromosomes 1. Autosomes – 22 pairs 2. Sex Chromosomes– 1 pair

7. CHROMOSOMES B. Sex Chromosomes a. determine male or female b. XX = Female c. XY = Male

8. Terminology • Chromatin – the relaxed, uncoiled state of the chromosome. • Chromosome – threadlike structures within the nucleus containing genetic information that is passed from generation to generation.

9. When chromosomes are preparing to divide the DNA replicates itself into two strands called chromatids. Held together by a centromere

11. Cell Division in Prokaryotes Binary Fission

12. BINARY FISSION • The process whereby bacteria copy their chromosome and then divide into two different cells.

13. BINARY FISSION

14. Cell Division in eukaryotes MITOSIS AND MEIOSIS

15. CELL DIVISION Mitosis Meiosis Occurs in sex cells called GAMETES Examples egg cells, sperm cells Mixes for genetic variation (sexual reproduction) • Occurs in body cells called SOMATIC CELLS • Examples muscle cells, cheek cells, liver cells, bone cells, red blood cells, etc. • Makes exact copies (asexual reproduction)

16. Why must cells divide? Cell division is necessary for: • Growth • Repair • Replacement of dying cells (such as skin cells or red blood cells) • Reproduction of an organism.

17. Most cells go through a series of changes in order to maintain homeostasis. • Cells need to reproduce when their surface area can no longer supply the much larger volume with nutrients and rid wastes.

18. Thecell cycle

19. Cell Cycle The process of cell division is called the cell cycle.

20. Interphase The first part of the cell cycle is called Interphase Interphase consists of three stages: -Normal cell activity -DNA (the chromosomes) replication -Final preparation for division It is the longest phase of the cell cycle.

21. The Cell Cycle

22. Cell cycle The next phase of the cell cycle is mitosis.

23. Mitosis Purpose - to produce an exact copy of a diploid cell. • After interphase, MITOSIS begins-4 phases(PMAT) • Prophase • Metaphase • Anaphase • Telophase

34. Cytokinesis in an Animal Cell Cleavage Furrow

35. Cytokinesis in an Plant Cell

36. Cytokinesis Cleavage furrow Animal cell Cell plate Plant cell

37. Cell division Which type of cells undergo mitosis?

38. Cell division Which type of cells undergo mitosis? All somatic cells.

39. Mitosis Mitosis produces two exact copies of the original cell. 2 Diploid Somatic Cells

40. Mitosis and cancer When Making New Cells Goes Terribly Wrong

41. When is mitosis a BAD thing • When cells reproduce & they are not needed • these cells take over organs, but don’t do the right job • they just keep making copies • cancer • damages organs

42. Why would cells just make copies? • If DNA gets damaged, cells stop listening to correct instructions _Mutation: change in genetic makeupand cause cells to become cancerous • Causes of mutations: • UV radiation • chemical exposure • radiation exposure • heat • cigarette smoke • pollution • age • genetics

43. Cancer-Causing Mutations • Exposure to environmental agents, virus, or lifestyle changes may cause a mutation • Certain virus infections can transform the cell • Human papillomavirus (HPV): Viral proteins interact with cell proteins, cause cervical cancer • Mistakes in DNA replication also cause mutations

44. Cancer • Carcinogens and certain behaviors increase rate of mutations and cancer risk • Not all tumors are cancerous, benign tumors,increase in size, but do not metastasize • Metastasis: Process in whichcells are invasive and move to other sites in the body

45. Cell Cycle Regulation • Normal cells contain check points to regulate the cell cycle. Stopping at appropriate points. • Cancerous cells do not respond to check points and continue rapidly through the cell cycle. This results in masses of undefined cells called tumors.

46. Tumors • Benign tumor • abnormal cells remain at original site as a lump • most do not cause serious problems &can be removed by surgery

47. Tumors • Malignant tumor • cells leave original site • carried by blood system to other tissues • start more tumors • damage functions of organs throughout body

48. Cancer Cells

49. Treatments for cancers • Treatments kill rapidly dividing cells • chemotherapy • poisonous drugs that kill rapidly dividing cells • radiation • high energy beam kills rapidly dividing cells

50. Licentious division - prostate cancer cells during division. Cancer Is One Outcome of A Runaway Cell Cycle