Microbio 160 Exam 1 Study Guide This study guide outline was provided by the professor however this is not the only document that you should study It is also important to review all lecture notes as well Material covered in the Kleinsmith text Chapter 1 3 and first half of chapter 4 Chapter 1 Cancer strikes older people more frequently than younger people and more cancer cases are being seen simply because people are living longer than they did in the past Lung cancer a disease that accounts for roughly one of every three cancer deaths in the United States Dysplasia An abnormal growth process that produces tissue in which proper cell and tissue organization has been disrupted It can range from mild moderate or severe Neoplasia Is an abnormal type of tissue growth in which cells proliferate in an uncontrolled relatively autonomous fashion leading to an continual increase in the number of growing cells This loss of cell creates a proliferating mass of abnormal cells called a neoplasm or tumor Cell Differentiation The process by which cells acquire the specialization properties that distinguish different types of cells from one another Benign tumors Grow in a confined local area Malignant tumors Can invade surrounding tissues enter the bloodstream and spread to distant parts of the body by metastasis Basal Cells Divide it gives rise to two cells with different fates One cell stays in the basal layer and retains the capacity to divide and undergoes differentiation as it leaves the basal layer and moves toward the outer skin surface Carcinomas are cancers that arise from the epithelial cells that form covering layers over external and internal body surfaces Sarcomas are cancers that originate in supporting tissues such as bone cartilage blood vessels fat fibrous tissue and muscle They are the rarest form of cancer About 1 of the total cancer diagnoses Lymphomas Refers to tumors of white blood cells that grow mainly as solid masses of tissue Chapter 2 uncontrolled nature Tumors must trigger the development of blood vessels that supply nutrients and oxygen to the tumor and remove waste products Without this step tumors cannot grow beyond a tiny size After tumors have triggered the formation of a blood supply cancer cells invade through surrounding tissues The distinctive feature of tumor growth is not the speed of cell division but it s Density dependent inhibition of growth routinely used when referring to the inhibition of cell division that occurs in crowded cultures Cancer cells are less susceptible to density dependent inhibition of growth than are their normal counterparts Cancer cells are anchorage independent so they do not need this A very large difference between cancer and normal cells in their lifespan Normal cells will usually divide only a limited number of times before they die Cancer cells have no such limit and behave as if they were immortal Placing such noncoding telomere DNA at the ends of each chromosome ensures that a cell will not lose any important information when DNA molecules are shortened slightly during replication since telomeres get shorter with each cell division they provide a counting device for tracking how many times the telomeres became extremely short and are in danger of disappearing entirely When this happens the telomeric DNA becomes too short to bind telomeric capping proteins or generate a loop exposing a bare end of double stranded DNA In normal cells such a hazardous outcome is prevented by a mechanism in which the unprotected DNA at the end of a chromosome triggers a pathway that halts cell division or triggers cell death Most cancer cells circumvent this problem by activating the gene that produces telomerase thereby causing new copies of the telomeric repeat sequence to be continually added to the ends of their DNA molecules For division cells pass through a series of discrete stages called G1 S G2 and M phase Called the cell cycle Taken together the G1 S and G2 phases are collectively referred to as interphase In such cases the cell cycle is halted in late G1 at a point referred to as the restriction point The ability of growth factors to promote passage through the restriction point by stimulating the production of CDK cyclins that phosphorylate Rb is just one example of how the cell cycle is controlled by external and internal factors that determine whether or not a cell should divide Such alterations cause an excessive production of the CDK Cyclins that phosphorylate the Rb protein thereby providing an ongoing stimulus for cells to pass through the restrictions point and pass P53 protein is heavily involved in apoptosis P53 coding gene is defective in cancer cells Chapter 3 Angiogenesis A term that refers to the proves by which new blood vessels sprout and grow from pre existing vessels in the surrounding normal tissues Angiogenesis is a normal biological event that occurs at specific times for specific purposes Vasculogenesis The newly created endothelial cells are organized into a primitive network of channels representing the major blood vessels of the circulatory system Angiogenesis is therefore activated a few days each month in the uterine lining of women of reproductive age In both male and female angiogenesis is also called upon anytime an injury requires new blood vessels for wound healing and tissue repair Angiogenesis needs to be precisely regulated in such cases It was suggested that tumors release signaling molecules that trigger the growth of new blood vessels in the surrounding host tissues And that these new blood vessels are required to sustain tumor growth Virtually every tumor stopped growing at exactly the same size suggesting that some kind of limitation allowed them to grow only so far This process by which cancer cells stimulate the development of a blood supply is called tumor angiogenesis Two of the proteins vascular endothelial growth factor VEGF and Fibroblast growth factor FGF appear to be specifically important for sustaining tumor growth For angiogenesis to proceed these molecules must overcome the effects of angiogenesis inhibitors that normally restrain the growth of blood vessels Tumor dormancy In which cancer cells spread from a primary tumor to another organ and form tiny clumps of cancer cells that remain dormant for prolonged periods of time Invasion Refers to the direct migration and penetration of cancer cells into neighboring tissues whereas metastasis involves the ability of cancer cells to
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