Chapter 10-3 Regulating the Cell Cycle

Transcription

1 Chapter 10-3 Regulating the Cell Cycle Vocabulary: Cyclin Cancer Key Concepts: How is the cell cycle regulated? How are cancer cells different from other cells?

2 I. Introduction A. An Interesting Fact About Cell Division 1. Not all cells move through the cell cycle at the same rate a. Ex: most muscle cells & nerve cells do not divide at all once they have developed whereas skin cells grow and divide rapidly throughout life

3 II. Controls on Cell Division A. Controls can be observed in a lab 1. Cells in a petri dish containing nutrient broth (food) will grow and divide forming a thin layer. 2. When the cells come into contact with each other, they stop growing

4 Controls on Cell Division continued If cells from the center are removed, growth and division will continue until cells are touching once again When have you witnessed this happening with your own body? Mitosis Functions = Growth and Repair!

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6 Right after a bone breaks, cells at the edge of the injury A. stop dividing. B. begin to divide rapidly. C. form a thin layer over the edge of the injury. D. develop a defect in a gene called p53. 0% 0% 0% 0% stop dividing. begin to divide rapidly. form a thin layer over the e... develop a defect in a gene c... Answer Now 15

7 B. Cell Cycle Regulators 1. Several scientists discovered that cells in mitosis contained a specific protein 2. If this protein was injected into a nondividing cell, the mitotic spindle would start to form 3. They called this protein CYCLIN because it seemed to regulate the cell cycle

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9 4. Scientists have since discovered a family of closely related proteins (cyclins) & dozens of other proteins that help regulate the cell cycle in eukaryotic cells

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11 In eukaryotic cells, the timing of the cell cycle is regulated by A. the centrioles. B. cyclins. C. the spindle. D. all of the above 0% 0% 0% 0% the centrioles. cyclins. the spindle. Answer Now 15 all of the above

12 C. Internal vs. External Regulators 1. INTERNAL: a. Proteins that respond to events inside the cell b. Some of these proteins make sure the cell does not enter mitosis until all of the chromosomes have been replicated

13 When cytoplasm from a cell that is undergoing mitosis is injected into a cell that is in interphase, the second cell A. stays in interphase. B. enters mitosis. C. stops making cyclin. D. loses its p53. 0% 0% 0% 0% stays in interphase. enters mitosis. stops making cyclin. loses its p53. Answer Now 15

14 2. EXTERNAL: a. Proteins that respond to events outside the cell b. Direct cells to speed up or slow down cell growth & division

15 Which of the following is a factor that can stop normal cells from growing? A. contact with other cells B. growth factors C. a cut in the skin D. cyclin that has been taken from a cell in mitosis 0% 0% 0% 0% contact with other cells growth factors a cut in the skin Answer Now 15 cyclin that has been taken fr..

16 Which of the following is an internal regulator of the cell cycle? A. cyclins B. growth factors C. the mitotic spindle D. cancer cells 0% 0% 0% 0% cyclins growth factors the mitotic spindle cancer cells Answer Now 15

17 Cells grown in a petri dish tend to divide until they form a thin layer covering the bottom of the dish. If cells are removed from the middle of the dish, the cells bordering the open space will begin dividing until they have filled the empty space. What does this experiment show? A. When cells come into contact with other cells, they stop growing. B. The controls on cell growth and division can be turned on and off. C. Cell division can be regulated by factors outside the cell. D. all of the above When cells come into conta.. 0% 0% 0% 0% The controls on cell growth... Cell division can be regulate... all of the above Answer Now 15

18 III. CANCER Uncontrolled cell growth A. General Info 1. Cancer cells do not respond to body s control mechanisms (such as cyclins) be.com/watch? v=lepttolebq o

19 2. Cancer cells divide excessively, may invade other tissues, and can kill the organism if left unchecked. 3. Cancer is a Disease of the Cell Cycle!

20 Cancer is a disorder in which some cells have lost the ability to control their A. size. B. spindle fibers. C. growth rate. D. surface area. 0% 0% 0% 0% size. spindle fibers. growth rate. surface area. Answer Now 15

21 4. Normally, the immune system recognizes and destroys cells which are growing abnormally a. Immune system does not respond to the cancer cell s antigens, so no immune response occurs 5. Oncology= branch of medicine studying cancer Normal cell

22 B. Characteristics of Cancer cells (How are they different from normal cells?) 1. Structure (Anaplasia) a. Cancer cells no longer resemble the same structure as a mature normal cell b. They also don t perform the same functions as the normal mature cell would

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25 2. Invasive a. Cancer cells invade surrounding tissue b. Cancerous cells affect the surrounding normal cells by depriving normal cells of nutrients and space

26 Benign tumor (osteoma) Normal bone Malignant tumor (osteogenic sarcoma)

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28 3. Metastasis = spreading a. In the final stages, cancer cells enter the circulatory and /or lymphatic system and spreads throughout the body forming new tumors in other organs that disrupt the functioning organs

29 LE 12-19a Tumor Glandular tissue A tumor grows from a single cancer cell. Cancer cells invade neighboring tissue.

30 LE 12-19b Lymph vessel Blood vessel Cancer cell Cancer cells spread through lymph and blood vessels to other parts of the body. Metastatic tumor A small percentage of cancer cells may survive and establish a new tumor in another part of the body.

31 b. Common sites of origin i. Lung, Breast, Skin: melanoma (other skin tumors rarely metastasize), Colon, Kidney, Prostate, Pancreas, Liver, Cervix

32 C. Are all tumors (masses of cells) MALIGNANT (Bad)? 1. No, only cells that invade the surrounding tissues are malignant

33 2. If the cells remain at the original site and is not invading the surrounding tissue, the mass is called a BENIGN TUMOR (not cancer) and can be completely removed by surgery.

34 D. What causes the loss of growth control? 1. Changes in one or more of the genes (DNA) that is involved in the Cell Cycle a. Some cells no longer respond to external growth regulators b. Other cells fail to produce the internal regulators that ensure orderly growth

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37 Cancer cells form masses of cells called A. tumors. B. cyclins. C. growth factors. D. p53. 0% 0% 0% 0% tumors. cyclins. Answer Now 15 growth factors. p53.

38 2. Causes can be inherited (received in genes from parents) and/or environmental a. Tobacco (Smoke and Smokeless) b. Radiation exposure i. UV Radiation from sun HUMAN LUNG

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41 According to: _Breast_Cancer/inherited_breast_cancer.html Reliable Statistics???? Other sites say less than 5% are inherited factors

42 c. Viral infection d. Asbestos e. Chemicals

43 There are many causes of cancers, including: Benzene and other chemicals Certain poisonous mushrooms and a type of poison that can grow on peanut plants (aflatoxins) Certain viruses

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46 Hazards of Tobacco Pictures (Use chrome

47 E. Treatments Depends upon the characteristics of the lesion 1. But most people have a combination of treatments, such as surgery with chemotherapy and/or radiation therapy. 2. There is also immunotherapy, targeted therapy, or hormone therapy.

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50 Chemotherapy

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57 F. Research p53 1. Many cancer cells have a defect in a gene called p53 2. The protein made from this segment of DNA normally halts the cell cycle until all chromosomes have been replicated properly (without mutations)

58 3. If it isn t working, damaged DNA can replicate 4. The cell may have lost the information it needs to respond to the growth control signals thus it divides out of control a. Remember: Cancer is a disease of the cell cycle

59 A cell with a defective p53 gene is likely to A. divide normally. B. stop dividing. C. accumulate chromosomal damage. D. combat tumors. 0% 0% 0% 0% divide normally. stop dividing. accumulate chromosomal d... combat tumors. Answer Now 15

60 Which of the following regulate(s) the cell cycle? A. growth factors B. cyclins C. p53 D. all of the above 0% 0% 0% 0% growth factors cyclins Answer Now 15 p53 all of the above

61 Cancer affects A. humans only. B. most unicellular organisms. C. multicellular organisms. D. unicellular organisms. 0% 0% 0% 0% humans only. most unicellular organisms. multicellular organisms. unicellular organisms. Answer Now 15

62 IV. Stem Cell Research A. Stem cell Definition and Development: 1. Stem cells are unspecialized cells that have the potential to differentiate to become specialized in structure and function into a wide variety of cell types

63 a. The type of cell is dependent upon the types and amounts of proteins that that cell produces

64 2. Stem cells develop into any number of specialized cells like blood cells, nerve cells, etc. but they are most abundant in developing embryos. 3. They can also be found in adults.

65 B. Why is stem cell research important in fighting disease? 1. Even though your body produces billions of new cells every day, it cannot replace all cells that are lost due to injury or disease.

66 2. Research in mice suggest that stem cells implanted into injured areas can actually reverse tissue lose due to this damage (generate new cell growth).

67 3. This new development may help us find cures for brain injuries, spinal cord injuries, liver disease, heart disease, etc.

68 C. Ethical and Moral Question: 1. Stem cells are most abundant in human embryos. Watch Youtube Video & Answer Questions: A Stem Cell Story: _Y&feature=youtu.be&list=UUWRE5KuOGcxisn LxgkTJAMg 2. Should human embryos be used to obtain stem cells for research to find cures to these diseases? 3. What about adult stem cells, are they useful in research?

69 National Cancer Institute: