Slide 1 of 18 Copyright Pearson Prentice Hall 10-3 Regulating the Cell Cycle

Slide 2 of 18 Copyright Pearson Prentice Hall Curriculum Outcomes: -Understand ways cell division is controlled. -Understand the link between mitosis and cancer. -Understand methods used to treat cancer.

10-3 Regulating the Cell Cycle Slide 3 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.

Slide 4 of Regulating the Cell Cycle Copyright Pearson Prentice Hall Controls on Cell Division Contact Inhibition

10-3 Regulating the Cell Cycle Slide 5 of 18 Copyright Pearson Prentice Hall Cell Cycle Regulators How is the cell cycle regulated?

Slide 6 of 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.

Slide 7 of 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

Slide 8 of 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

Slide 9 of 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. Growth factors are one of the most important external regulators.

10-3 Regulating the Cell Cycle Slide 10 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?

10-3 Regulating the Cell Cycle Slide 11 of 18 Copyright Pearson Prentice Hall Uncontrolled Cell Growth Cancer cells do not respond to the signals that regulate the growth of most cells.

Slide 12 of 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. An astonishing number of cancers are caused by a damaged or defective “p53” gene that helps regulate cell growth.

Slide 13 of Regulating the Cell Cycle Copyright Pearson Prentice Hall Cancers can be treated in different ways. 2 common treatment methods are chemotherapy and radiation.

Slide 14 of Regulating the Cell Cycle Copyright Pearson Prentice Hall Radiation works by damaging the genes in a cell. When a cell’s genes are damaged, it interferes with its ability to grow and divide. Over time, the cells die. Radiation targets cells that are actively dividing, whether they are healthy cells or cancerous. Radiation treatment acts on one localized area.

Slide 15 of Regulating the Cell Cycle Copyright Pearson Prentice Hall Chemotherapy is the use of drugs to treat cancer. Drugs are injected and travel through the body to reach the cancer cells. Most chemotherapy drugs work only on cells that are actively reproducing, whether they are healthy cells or cancerous. Some drugs attack cells during certain phases of the cell cycle (ex: M or S phase).

Slide 16 of Regulating the Cell Cycle Copyright Pearson Prentice Hall Different chemicals work in different ways. One may attack the cell's genetic material (DNA or RNA) to stop growth, while another may cause the cells to die by preventing proteins inside the cell from working properly.

- or - Continue to: Click to Launch: Slide 17 of 18 Copyright Pearson Prentice Hall 10-3

Slide 18 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 19 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 20 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 21 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 22 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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