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Download U5-Topic2_Eukaryotic cell cycle and cancer
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Grade 11A Name:______________________________ Class: _________________ Active reading 11A – Biological basics of inheritance Topic 2: Eukaryotic cell cycle and cancer As a cell grows, it gets larger. Eventually it divides to form two daughter cells. Each daughter cell then grows, gets larger, and eventually divides. This repeating sequence of cellular growth and division is called the cell cycle. The eukaryotic cell cycle is made up of five phases, as shown in the figure. During three of the phases, the cell is growing. Together these three phases are known as interphase. During the other two phases, the cell is dividing. These two phases together are known as cell division. During mitosis, the nucleus of the cell divides and forms two nuclei. Each nucleus contains a complete set of chromosomes. During cytokinesis the cell membrane grows into the center of the cell. The membrane divides the cell into two daughter cells that are about the same size Grade 11A Name:______________________________ Class: _________________ If you get a cut, the wound will heal as new skin cells are produced. These skin cells with stop dividing once the cut has been healed. If they continued to divide, they would start piling up at the site of the cut. Signals from within the cell, from other cells, or from the environment cause cells to grow, divide, or stop growing. Remember that there are different phases of the cell cycle. Cells move from one phase to the next. However cells cannot move between phases at just anytime. The cell must not move on to the next phase until conditions are right. The environment must also be favorable for the cell to move on. To ensure that cells move on only when they are ready, there are several checkpoints in the cell cycle. At each checkpoint, feedback signals tell the cell whether or not to move to the next phase. There are three main checkpoints in the eukaryotic cell cycle, as shown below. Normally, the signals and controls in the cell cycle determine when a cell divides or grows. However, damage to a cell’s DNA can cause the cell to stop responding properly to signals. If this happens, the cell may start to divide in an uncontrolled way. The result can be cancer. Cancer is a disease that is caused by uncontrolled Grade 11A Name:______________________________ Class: _________________ cell growth and division. There are many kinds of cancer. Cells that continue dividing in an uncontrolled way may form a mass called a tumor. Tumors can divide and destroy healthy tissue. There are two main kinds of tumors: benign and malignant. Type of tumor Benign Description Does not spread to other parts of the body Most can be removed through surgery Invades nearby healthy tissue Pieces of the tumor may break off and travel to other parts of the body (metastasis) Can be more difficult to treat than benign tumors Malignant The treatment for cancer depends on which type of cancer a person has. Many cancers are treated by chemotherapy, which involves using drugs to kill cancer cells. In some cases doctors can use radiation to kill cancer cells. Surgery can also be used to treat cancers. In many cases a combination of treatment is used. The best way to reduce the risk of cancer is to reduce your exposure to things that can cause cancer. Although many cancers occur for unknown reasons, there are some things that can make caner more likely by damaging DNA. For example, ultraviolet radiation can damage DNA. In some cases, a person’s habits may make cancer more likely. For examples chemicals in cigarette smoke can damage DNA. Therefore smoking can increase the risk of cancer. Key words Eukaryotic cell Cytokinesis Cell cycle Tumor Interphase Chemotherapy Mitosis Cell division Grade 11A Name:______________________________ Class: _________________ A. Write one or more sentences to answer the following questions 1. Define what is interphase? _____________________________________________________________ _____________________________________________________________ 2. Describe what happens during the G1 phase of the cell cycle? _____________________________________________________________ _____________________________________________________________ 3. Identify what two process make up cell division? _____________________________________________________________ _____________________________________________________________ 4. What do you think is one condition that a cell must meet before it can move from the G1 phase to the S phase? _____________________________________________________________ _____________________________________________________________ 5. What happens at the metaphase checkpoit? _____________________________________________________________ _____________________________________________________________ 6. What can cause a cell to stop responding to signals? _____________________________________________________________ _____________________________________________________________ 7. How is cancer related to cell cycle? _____________________________________________________________ _____________________________________________________________ Grade 11A Name:______________________________ Class: _________________ 8. How do feedback signals affect the cell cycle? _____________________________________________________________ _____________________________________________________________ B. Fill in the graphic organizers 1. Mitosis Cytokinesis How are they different? __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ 2. Benign tumor Malignant tumor How are they different? __________________ __________________ __________________ __________________ __________________ __________________ __________________ __________________ Grade 11A Name:______________________________ Class: _________________ C. Circle the letter of the phrase that best answers the question. 1. Replication of the genome occurs in the ______ phase of the cell cycle. a. G1 b. G2 c. M d. S 2. At the end of cell division, each daughter cell has the same number of chromosomes but half the amount of DNA that the parent cell had when it was in G2 of the cell cycle. a. True b. False 3. Which of the following terms is not related to mitosis? a. Gametes b. Chromosomes c. DNA replication d. somatic cells 4. The cell cycle is controlled in most cells by … a. time, after a certain length of time the cell divides b. a series of checkpoints c. the completion of one phase which triggers the beginning of the next d. cell size, when the cell reaches a certain size, it divides Grade 11A Name:______________________________ Class: _________________ D. Make a flowchart describing the phase of the eukaryotic cell cycle. E. Discuss in a small group, talk about any habits or conditions in your life that might increase your risk of cancer. How can you reduce your risk?
