Biology Slide 1 of 18 Copyright Pearson Prentice Hall Cell Division Regulation of the cell cycle Slide 2 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle Controls on Cell Division Controls on Cell Division a.Contact with other cells – cell growth stops This demonstrates that controls on cell growth and division can be turned on and off. b. regulators Slide 3 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle Controls on Cell Division Contact Inhibition Slide 4 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle Cell Cycle Regulators How is the cell cycle regulated? Slide 5 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle Cell Cycle Regulators Cell Cycle Regulators Cyclins regulate the timing of the cell cycle in eukaryotic cells. Slide 6 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle Cell Cycle Regulators Cyclins were discovered during a similar experiment to this one. A sample of cytoplasm is removed from a cell in mitosis. The sample is injected into a second cell in G2 of interphase. As a result, the second cell enters mitosis. Slide 7 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle Cell Cycle Regulators Internal Regulators Proteins that respond to events inside the cell allow the cell cycle to proceed only when certain processes have happened inside the cell. Slide 8 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle Cell Cycle Regulators External Regulators outside the cell are called external regulators. External regulators direct cells to speed up or slow down the cell cycle. Slide 9 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle Uncontrolled Cell Growth 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? Slide 10 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle Uncontrolled Cell Growth Cancer cells do not respond to the signals that regulate the growth of most cells. Slide 11 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle Uncontrolled Cell Growth Tumors – masses of cells that can damage the surrounding tissues. Metastasis - cells may break loose from tumors and spread throughout the body, disrupting normal activities and causing serious medical problems or even death. Slide 12 of 18 Copyright Pearson Prentice Hall 10-3 Click to Launch: Continue to: - or - Slide 13 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. Slide 14 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. Slide 15 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. Slide 16 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. Slide 17 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. Slide 18 of 18 Copyright Pearson Prentice Hall END OF SECTION