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Investigation 4.3
School Analogy |
Sometimes we use analogies such as the corn analogy to help us understand things we cannot see. You might think of a school when you try to understand a cell. |
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First let's think about your school. Take two minutes on your own and think about what parts a school has and what these parts do. Do not include people but only the five most important spaces such as rooms. |
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Share these ideas with your group and write them on your whiteboard. |
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As your teacher directs you, send one of your group to the front of the room to display your whiteboard. |
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Look at what all the groups have written. Do you see any parts of the school that they all have in common? |
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Now we will select just five of these school parts and compare them to the cell. These are the parts that are most similar. |
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As the teacher leads you, fill in the five school parts in the top shape on the page in your lab book. |
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Think about the parts of the school we have just entered in the drawings. With your group come up with the functions of each part. |
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1. Think specifically about what happens in the classrooms. Does anything get produced there? Does it stay in the classroom or is it ever sent out? |
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2. Now what about the main office. What is its function? |
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3. Why does the school have hallways? |
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4. What about the trash receptacles? Does all the trash in the school remain in the school or is it sent somewhere? |
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5. Finally, what is the cafeteria for? Do you see any connection between the cafeteria and what you learned earlier about energy and digestion? |
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Go back to your drawing of the school and write these functions next to each part. |
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Now share your ideas with the rest of the class. Be sure everyone is ready to answer questions about your answers. |
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Your teacher will again direct you to the two shapes on the board. Now you will begin to map the parts of the school to possible parts of a cell. Remember this is an analogy, not the real thing. It will help you to remember the structure and function of the cell. |
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Use the figures in your lab book to map the school parts to the cell. |
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You have mapped the parts of the school to the parts of a cell. It is more important right now to understand what the function of these parts is rather than being overly concerned about their names. You will learn more about their names later. |
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Look back at the functions you gave to the parts of the school. |
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With your group discuss the following questions: |
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If the Golgi body is like the classroom, what might its function be? Do you think that it could produce anything? If it did what do you think it might be? |
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We have suggested that the main office in the school is like the nucleus of the cell. Name some of the things the nucleus could do. |
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The lysosomes are like the trash receptacles. What is their job? |
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If the endoplasmic reticulum works similar to the hallways in the school, what is its function? |
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Finally, you have mapped the cafeteria to the mitochondrion of the cell. Think about the role the cafeteria plays in the school. If the cafeteria is responsible for providing energy sources in the form of food for students, how do you think the mitochondrion might provide a similar service for the cell? |
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You will be investigating the mitochondrion in more detail in the next chapter. |
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We have suggested that a school is like a cell. Can you think of another analogy that might work just as well to describe the function of a cell? |
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Draw and label it in your lab book. |
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Share your new analogy with your group. Ask each other questions until you are sure that you all understand how the analogy is like a cell. Be ready to share with the rest of the class. |
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As you recall, when you looked at cells under the microscope it was difficult to see much more than a few dots inside individual cells. This was because the cells were so small and the organelles inside are even smaller. It would take a powerful electron microscope to be able to see organelles like the Golgi bodies or mitochondria. |
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However, artists have used pictures taken from these powerful microscopes to make model drawings that give us an idea how the inside of a cell would look. Your teacher will show you some of these pictures along with actual electron microscope pictures. |
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As you observe the pictures, ask yourself: |
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- " Do these pictures look like the model of a cell that I have in my head? "
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- Do you agree with the artist's model? Are there things about it that you question?
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Look back at the original drawing you made of a generic cell. |
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How has your model of a cell changed? |
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How is the school analogy different from the ear of corn analogy? |
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Draw your new model in the circle in your lab book. Be sure to label all the parts and make a brief description of how each works. |
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