Cell Cycle Worksheet

The Eukaryotic Cell Cycle and Cancer Overview 1. Why is cell division important for both single-celled and multicellular organisms? Unicellular organisms use cell division as a way of reproduction whereas, multicellular organisms use cell division to replace cells that have otherwise become damaged or died. 2. Why does cell division remain important to an adult organism even after it is fully developed? Cell division remains a necessity in fully developed adult organisms because cell repair is a continuously needed function, be it due to injury or damage to cells. 3. Cells divide, differentiate, or die. What is differentiation? Cell differentiation is when a cell forms to become specialized losing capability of mitosis and instead becoming a specifically functioning cell. 4. What is apoptosis? What is its purpose? Apoptosis is the process of cell death while developing to remove abnormal cells from an organism in order to protect, regulate and maintain healthy cell growth and development within the organism. 5. What are cell cycle regulators? Cell cycle regulators are a type of proteins known as cyclin and cyclin dependent kinases that send signals for cell division to either continue or stop within an organism. 6. What happens if cell cycle regulators don’t function properly? If cell cycle regulators do not function correctly within an organism the creation of new cells could cause too many or vice versa the depletion of needed cells though the largest risk of malfunctioning cell cycle regulators is the creation and halt of death for abnormal cells which could cause irreparable damage to an organism. Click on the purple section labeled “Cell Cycle Phases” as well as the words “Mitosis” and “Interphase” to read an overview of the cell cycle. You can also click on the various phases. mitosis 7. Cells go through periods of growth and division. Cell division occurs during ____________________. The rest of the cell cycle is called interphase, during which (use the blank below to complete the sentence) cells grow and make duplicated copies of DNA within an organism. 8. Fill in the details about what happens during the three phases of interphase labeled in the diagram. growth and DNA synthesis preparation replication and synthesis of DNA growth and mitosis preperation 9. In general, what is the purpose of a checkpoint in the cell cycle? The checkpoints within a properly functioning cell cycle allow for cells to undergo restrictions of regulators and apoptosis before creating duplicates and cell growth to avoid damaged cells from entering the mitosis phase of the cell cycle. 10. What is the G0 phase of the cell cycle? a. Which factors determine whether a cell enters G0? A cell enters the G0 stage of the cell cycle if the G1 checkpoint signals a cell has deficient growth or nutrients to divide. b. Can cells leave G0? Cells can leave the G0 when an organism is growing and follow the cell cycle processes to enter into mitosis. Click on “Cell Cycle Regulators and Cancer” in the center purple circle. Read the “Regulators Overview” and then read through the “Cancer Overview” and watch the videos. 11. What are cell cycle regulators? Cell cycle regulators are a type of proteins known as cyclin and cyclin dependent kinases that send signals for cell division to either continue or stop within an organism. proto-oncogenes a. Stimulating proteins are encoded by ______________________________________. CDK's Examples include: _____________________________________________________ Tumor suppressor genes b. Inhibitory proteins are encoded by ________________________________________. p53 Examples include: _____________________________________________________ 12. Cancer is the result of an improperly regulated cell cycle. Describe two reasons why cells can form tumors. Mutations within tumor suppressor genes or proto- oncogenes are causes for tumors within an organism. 13. In some types of colon cancer, stem cells have a mutation in the APC gene. What happens if the APC gene is mutated? When stem cells have a mutation within an APC gene the formation of tumors can occur within the colon causing colon cancer to form. 14. Normally, proto-oncogenes stimulate the cell cycle. What are oncogenes and how do they affect the cell cycle? Mutated forms of proto- oncogenes are referred to as oncogenes , these mutated cells can cause the cell cycle to become over stimulated causing to much cell growth and over exertion of the cell cycle. 1 a. To cause cancer, proto-oncogenes require _________ allele(s) to be mutated and therefore are dominant gain considered ______________________ . The mutation results in a ________ of function. 15. Normally, tumor suppressor genes inhibit the cell cycle. How do mutated tumor suppressor genes affect the cell cycle? Mutated tumor suppressor genes continue to inhibit the cell cycle causing a decrease in mitosis or malfunction in repair and apoptosis. 2 a. To cause cancer, tumor suppressor genes require __________ allele(s) to be mutated and therefore are recessive loss considered ______________________ . The mutation results in a ________ of function.