So Far…

1. So Far… • You have learned that cells undergo division to produce more cells for three reasons. • You have also learned the stages of the cell cycle and mitosis. • Does this process go on uncontrolled? • If not, what’s the control like? • What happens when the control is lost.

2. The graph shows the number of cigarettes smoked per capita per year between 1920 and 2000 and the annual incidence of lung cancer among women. Use the graph to answer the following question(s).

3. 7. What was the relationship between the number of cigarettes smoked and the incidence of lung cancer?

4. The graph shows the number of cigarettes smoked per capita per year between 1920 and 2000 and the annual incidence of lung cancer among women. Use the graph to answer the following question(s). • Graph Analysis Review • What is the independent variable? • What is the dependent variable?

5. Objectives:Cell cycle regulation • Identify some factors that control cell growth and division. • Describe the effect of environmental conditions on the cell cycle. • Illustrate how feedback signals affect the cell cycle by summarizing the events of each of the three checkpoints of the cell cycle. • Restate how cancer relates to the cell cycle. • Distinguish between a benign tumor and a malignant tumor.

6. Vocabulary • Cancer • Tumor • Benign • Malignant

7. Controls • Cell division is highly controlled. • What are the three factors that regulate cell growth & division? • Cell growth and division depends three main factors. • 1. PROTEINS: There are many proteins within the cell that control the phases of the cell cycle. • 2. SIGNALS: Signals from surrounding cells or even from other organs can also regulate cell growth and division. • 3. SURROUNDINGS: Environmental conditions, including the availability of nutrients, also affect the cell cycle.

8. Visual Concept: Control of the Cell Cycle

9. Checkpoints • During the cell cycle, a cell undergoes an inspection process to ensure that the cell is ready for the next phase in the cell cycle. • Feedback signals at key checkpoints in the cell cycle can delay or trigger the next phase of the cell cycle. • There are three main checkpoints in the cell cycle • G1 Checkpoint • G2 checkpoint • Mitosis checkpoint.

10. Checkpoints For cells that will divide, this checkpoint ensures that the surroundings are right for DNA duplication & division. After chromosomes are split into tow separate nuclei (after telophase) the cell makes sure they are split up evenly. If so the cell divides, if not the cell gets destroyed. Cells like nerve cells never get out of this stage. Cells like muscle will spend a long time in this phase. After DNA is copied in the S phase, it is critical that it has been done correctly. The cell checks the copies and proceeds to mitosis only if the DNA is copied exactly.

11. WHAT HAPPENS WHEN CELL DIVISION GOES WRONG!!!!

12. Broken Checkpoints If DNA gets damaged then the cells can’t check it’s surroundings correctly If faulty DNA is copied & distributed into separate nuclei then these cells can proceed to produce daughter cells. This could lead to tumor formation if it’s not detected. This could lead to faulty DNA to be copied. If faulty or damaged DNA is copied, this could be allowed to proceed into mitosis.

13. Uncontrolled Growth • When the cell cycle goes unchecked or unregulated things get bad in the body. • The most common result… CANCER

14. Cancer • Each year, more than 1 million Americans are diagnosed with cancer. • Canceris a group of severe and sometimes fatal diseases that are caused by uncontrolled cell growth. • Uncontrolled cell growth and division can result in masses of cells that invade and destroy healthy tissues.

15. Cancer, continued Loss of Control • Normally, a cell responds properly to signals and controls. • In these times, cells only divide when they are supposed to. • When DNA, and the genes associated with them, gets damaged the signals and proteins don’t work properly. • The defective cell divides and produces more defective cells. Eventually, these cells can form a mass called a tumor. • [Tumor: a growth that arises from normal tissue but that grows abnormally in rate and structure and lacks a function]

16. They can develop anywhere… • Brain

17. Lungs

18. Lymph nodes

19. Other areas • Testicles • Breasts • Skin • Stomach • Eyes • See the theme? • Any cell or organ that has DNA & goes through mitosis can get cancer.

20. Cancer Development • A benign tumor does not spread to other parts of the body and can often be removed by surgery. • These tumors are generally not that harmful. • A malignant tumor invades and destroys nearby healthy tissues and organs. • These are the tumors to be afraid of. • Malignant tumors, or cancers, can break loose from their tissue of origin and grow throughout the body. This process is called metastasis. Once a cancer has metastasized, it becomes difficult to treat.

21. Causes • There are many causes of cancer but for the most part they come from… • Carcinogens • Intercalating compounds • Anything else that causes irreversible damage to the genes in DNA responsible for regulating cell growth & development. • http://www.cancer.org/Cancer/CancerCauses/OtherCarcinogens/GeneralInformationaboutCarcinogens/known-and-probable-human-carcinogens

22. Causes • Smoking • Lung cancer • Alcohol • Esophageal carcinoma

23. Causes • Ultraviolet (UV) or other forms of radiation; from the sun, atomic weapons & reactors, radioactive matter (uranium), etc. • Basal carcinoma • Melanoma

24. Causes • Cell phones? • Brain tumors • We’ll see the data in your generation.

25. CancerTreatment • Some cancers can be treated by using drugs that kill the fast-growing cancer cells. • Because drugs are chemicals, this method of treatment is called chemotherapy, or “chemo” for short. • Some cancers can be treated by surgery to remove of the affected organ. • Ultra-refined lasers • In radiation therapy, high-energy rays are focused on an area in order to destroy cancerous cells. • There are homeopathic treatments available, a highly supported nouveau methodology that uses treatments that are much more natural, personalized, and supportive than traditional “big-pharma” treatments. • See: http://www.burzynskiclinic.com/ for an example.

26. Cancer, continued Prevention • The best way to prevent cancer is to avoid things that can cause cancer. • Wear sun block • Limit exposure to smoke • Limit exposure to alcohol intake • Limit micro-radio wave exposure • Avoid anything on the list of known carcinogens

27. Quiz Q1: What is cancer (define it)? Q2: How do cancer cells affect healthy cells? Q3: What is the reason that cancer cells do not respond properly to cell signals and controls? Q4: What can form in the body as a result? Q5: What is the difference between a benign tumor and a malignant tumor?

28. Q1: What is cancer (define it)? • A1: Cancer is a group of severe and sometimes fatal diseases caused by uncontrolled cell growth. Q2: How do cancer cells affect healthy cells? • A2: Cancer cells result in masses of cells, called a tumor, that invade and destroy healthy tissues. Q3: What is the reason that cancer cells do not respond properly to cell signals and controls? • A3: Damage to a cell’s DNA can cause the cell to respond improperly or stop responding to normal signals and controls. If this happens, the cell cycle can’t be controlled. The defective cell divides, producing more defective cells. A mass of these cells forms a tumor. Q4: What can form in the body as a result? • A4: Tumors Q5: What is the difference between a benign tumor and a malignant tumor? • A5: A benign tumor does not spread to other parts of the body. Benign tumors are usually easy to remove. Cells in malignant tumors invade and destroy nearby healthy tissues and organs; they can also break loose and spread to other parts of the body.

29. Summary • Cell growth and division depend on protein signals and other environmental signals. • Feedback signals at key checkpoints in the cell cycle can delay or trigger the next phase of the cell cycle. • Uncontrolled cell growth and division results in tumors, which can invade surrounding tissues and cause cancer.