1. Slide 1 of 18 Copyright Pearson Prentice Hall Biology

2. Slide 2 of 18 CLE: 3210.1.4 Describe the processes of cell growth and division. SPI3210.1.6 Determine the relationship between cell growth and cell reproduction. Copyright Pearson Prentice Hall

3. Slide 3 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle

4. Slide 4 of 18 Copyright Pearson Prentice Hall Controls on Cell Division Experiments show that normal cells will reproduce until they come into contact with other cells. When cells come into contact with other cells, they respond by not growing. This demonstrates that controls on cell growth and division can be turned on and off.

5. Slide 5 of 18 10-3 Regulating the Cell Cycle Copyright Pearson Prentice Hall Controls on Cell Division Contact Inhibition

6. 10-3 Regulating the Cell Cycle Slide 6 of 18 Copyright Pearson Prentice Hall Cell Cycle Regulators How is the cell cycle regulated?

7. Slide 7 of 18 10-3 Regulating the Cell Cycle Copyright Pearson Prentice Hall Cell Cycle Regulators The cell cycle is regulated by a specific protein. The amount of this protein in the cell rises and falls in time with the cell cycle. Scientists called this protein cyclin because it seemed to regulate the cell cycle. Cyclins regulate the timing of the cell cycle in eukaryotic cells.

8. Slide 8 of 18 10-3 Regulating the Cell Cycle Copyright Pearson Prentice Hall A sample of cytoplasm is removed from a cell in mitosis. The sample is injected into a second cell in G 2 of interphase. As a result, the second cell enters mitosis. Cyclins were discovered during a similar experiment to this one. Cell Cycle Regulators

9. Slide 9 of 18 10-3 Regulating the Cell Cycle Copyright Pearson Prentice Hall Internal Regulators Proteins that respond to events inside the cell are called internal regulators. Internal regulators allow the cell cycle to proceed only when certain processes have happened inside the cell. Cell Cycle Regulators

10. Slide 10 of 18 10-3 Regulating the Cell Cycle Copyright Pearson Prentice Hall Cell Cycle Regulators External Regulators Proteins that respond to events outside the cell are called external regulators. External regulators direct cells to speed up or slow down the cell cycle.

11. 10-3 Regulating the Cell Cycle Slide 11 of 18 Copyright Pearson Prentice Hall Uncontrolled Cell Growth Cancer is a disorder in which some of the body's own cells lose the ability to control growth. How are cancer cells different from other cells?

12. 10-3 Regulating the Cell Cycle Slide 12 of 18 Copyright Pearson Prentice Hall Uncontrolled Cell Growth Cancer cells do not respond to the signals that regulate the growth of most cells.

13. Slide 13 of 18 10-3 Regulating the Cell Cycle Copyright Pearson Prentice Hall Uncontrolled Cell Growth Cancer cells divide uncontrollably and form masses of cells called tumors that can damage the surrounding tissues. Cancer cells may break loose from tumors and spread throughout the body, disrupting normal activities and causing serious medical problems or even death.

14. Slide 14 of 18 10-3 Regulating the Cell Cycle Cells and cancer Cancer is a disease that originates in our own cells. A change in the DNA causes a special gene called an oncogene to be switched on. This leads to uncontrollable cell reproduction by mitosis. And this is a cancer. Copyright Pearson Prentice Hall

15. Slide 15 of 18 10-3 Regulating the Cell Cycle Copyright Pearson Prentice Hall Doctors often cannot explain why one person develops cancer and another does not. But research shows that certain risk factors increase the chance that a person will develop cancer. These are the most common risk factors for cancer: Ionizing radiation virusesviruses Growing older bacteria HormonesHormonesGGGGggggg Family

16. Slide 16 of 18 10-3 Regulating the Cell Cycle Growing older Tobacco Sunlight Alcohol Family history of cancer Poor diet, lack of physical activity, being overweight Copyright Pearson Prentice Hall

17. Slide 17 of 18 10-3 Regulating the Cell Cycle Some Viruses and Bacteria Being infected with certain viruses or bacteria may increase the risk of developing cancer: Human papillomavirusesHuman papillomaviruses (HPVs): HPV infection is the main cause of cervical cancer. It also may be a risk factor for other types of cancer. Hepatitis BHepatitis B and hepatitis C viruses: Liver cancer can develop after many years of infection with hepatitis B or hepatitis C.hepatitis C Copyright Pearson Prentice Hall

18. Slide 18 of 18 10-3 Regulating the Cell Cycle Human T-cell leukemia/lymphoma virusHuman T-cell leukemia/lymphoma virus (HTLV-1): Infection with HTLV-1 increases a person's risk of lymphoma and Humleukemia.Hum Human immunodeficiency virusHuman immunodeficiency virus (HIV): HIV is the virus that causes AIDS. People who have HIV infection are at greater risk of cancer, such as lymphoma and a rare cancer called Kaposi sarcoma. AIDSKaposi sarcoma Epstein-Barr virusEpstein-Barr virus (EBV): Infection with EBV has been linked to an increased risk of lymphoma. Human herpesvirus 8Human herpesvirus 8 (HHV8): This virus is a risk factor for Kaposi's sarcoma. Helicobacter pyloriHelicobacter pylori : This bacterium can cause stomach ulcers. It also can cause stomach cancer and lymphoma in the stomach lining. Copyright Pearson Prentice Hall

19. Slide 19 of 18 10-3 Regulating the Cell Cycle Copyright Pearson Prentice Hall

20. Slide 20 of 18 10-3 Regulating the Cell Cycle What is a cancer? The uncontrolled growth of cells forms a lump called a tumour. Some tumours are benign and may not cause any problems. Others however are malignant. They can invade into other body tissues and cause severe damage. It is these malignant tumours that we call cancer. There are over 200 different types of cancer and they can occur anywhere in the body. Copyright Pearson Prentice Hall

21. Slide 21 of 18 10-3 Regulating the Cell Cycle A tumor growth on a pair of kidneys (the growth is at the top of the picture). Roll over the image to highlight the tumor. Copyright Pearson Prentice Hall

22. Slide 22 of 18 10-3 Regulating the Cell Cycle Copyright Pearson Prentice Hall Tumors can be benign or malignant:benignmalignant Benign tumors are not cancer: Benign tumors are rarely life-threatening. Generally, benign tumors can be removed, and they usually do not grow back. Cells from benign tumors do not invade the tissues around them. Cells from benign tumors do not spread to other parts of the body.

23. Slide 23 of 18 10-3 Regulating the Cell Cycle Malignant tumors are cancer: Malignant tumors are generally more serious than benign tumors. They may be life-threatening. Malignant tumors often can be removed, but sometimes they grow back. Cells from malignant tumors can invade and damage nearby tissues and organs. Cells from malignant tumors can spread (metastasize) to other parts of the body. Cancer cells spread by breaking away from the original (primary) tumor and entering the bloodstream or lymphatic system. The cells can invade other organs, forming new tumors that damage these organs. The spread of cancer is called metastasis.primarylymphatic system metastasis Copyright Pearson Prentice Hall

24. Slide 24 of 18 10-3 Regulating the Cell Cycle Malignant tumors Cancers are dangerous types of growths called malignant tumors. In this type of tumor the cells invade the surrounding tissues. Cancer cells can break off and be carried to different parts of the body in the bloodstream. This spreads the cancer throughout the body where it can cause serious damage and eventually death. Copyright Pearson Prentice Hall

25. - or - Continue to: Click to Launch: Slide 25 of 18 Copyright Pearson Prentice Hall 10-3

26. Slide 26 of 18 Copyright Pearson Prentice Hall 10-3 The cell cycle is believed to be controlled by proteins called a.spindles. b.cyclins. c.regulators. d.centrosomes.

27. Slide 27 of 18 Copyright Pearson Prentice Hall 10-3 Proteins that respond to events inside the cell are called a.internal regulators. b.external regulators. c.cyclins. d.growth factors.

28. Slide 28 of 18 Copyright Pearson Prentice Hall 10-3 Once a multicellular organism reaches adult size, the cells in its body a.stop dividing. b.grow and divide at different rates, depending on the type. c.have the same life span between cell divisions. d.undergo cell division randomly.

29. Slide 29 of 18 Copyright Pearson Prentice Hall 10-3 One effect of an internal regulator is that a cell will not begin mitosis until a.it becomes too large. b.the cell’s growth is stimulated. c.it is in physical contact with other cells. d.all its chromosomes have been replicated.

30. Slide 30 of 18 Copyright Pearson Prentice Hall 10-3 One factor common to almost all cancer cells is a.a lack of cyclin. b.a defect in gene p53. c.exposure to tobacco smoke. d.exposure to radiation.

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