Name Date Class Lab A 40 minutes Mitosis and Meiosis During cellular reproduction, many changes occur in the nucleus of cells involving the chromosomes. You could think about these changes as a set of choreographed moves like you would see in a dance. In this lab, you will act out the moves that chromosomes make during mitosis and meiosis in order to understand the steps that occur when cells reproduce. Ask a Question How do chromosomes change and move during mitosis and meiosis? Materials pool noodles Safety Make Observations 1. Read and complete a lab safety form. 2. Form a cell nucleus with four chromosomes represented by students holding four different colors of pool noodles. Other students play the part of the nuclear membrane and form a circle around the chromosomes. chromosome with two sister chromatids. 4. Perform the following steps of mitosis. a. During prophase, the nuclear membrane breaks apart, and the nucleolus disappears. b. In metaphase, duplicated chromosomes align in the middle of the cell. c. The sister chromatids separate in anaphase. d. In telophase, the nuclear membrane reforms around two daughter cells. 5. Repeat steps 2 and 3. Then perform the following steps of meiosis. a. In prophase I, the nuclear membrane breaks apart, the nucleolus disappears, and homologous chromosomes pair up. b. In metaphase I, homologous chromosomes line up along the center of the cell. c. During anaphase I, the pairs of homologous chromosomes separate. d. In telophase I, the nuclear membrane reforms. 44 Reproduction of Organisms Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 3. The chromosomes duplicate during interphase. Each chromosome is copied, creating a Name Date Class Lab A continued e. Each daughter cell now performs meiosis II independently. In prophase II, the nuclear membrane breaks down, and the nucleolus disappears. Remember to use scientific methods. f. During metaphase II, duplicated chromosomes Ask a Question align in the middle of the cell. Make Observations Form a Hypothesis g. Sister chromatids separate in anaphase II. Test your Hypothesis h. In telophase II, the nuclear membrane reforms. Analyze and Conclude Form a Hypothesis Communicate Results 6. Use your observations to form a hypothesis about the results of an error in meiosis. For example, you might explain the results of an error during anaphase I. Test Your Hypothesis Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 7. Perform meiosis again, incorporating the error you chose in step 6. 8. Compare the outcome to your hypothesis. Does your data support your hypothesis? If not, revise your hypothesis and repeat steps 6–8. Analyze and Conclude 9. Compare and Contrast How are mitosis and meiosis I similar? How are they different? 10. The Big Idea What is the difference between the chromosomes in cells at the beginning and the end of mitosis? At the beginning and end of meiosis? Reproduction of Organisms 45 Name Date Class Lab A continued 11. Critique How did performing cellular replications using pool noodles help you understand mitosis and meiosis? Communicate Your Results Create a chart of the changes and movements of chromosomes in each of the steps in meiosis and mitosis. Include colored drawings of chromosomes and remember to draw the cell membranes. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Lab Tips • Figure out where the boundaries of your cell are before you start. • Review the phases of mitosis and meiosis before beginning to act out how the chromosomes move during each process. 46 Reproduction of Organisms Name Date Class Lab B 40 minutes Mitosis and Meiosis During cellular reproduction, many changes occur in the nucleus of cells involving the chromosomes. You could think about these changes as a set of choreographed moves like you would see in a dance. In this lab, you will act out the moves that chromosomes make during mitosis and meiosis in order to understand the steps that occur when cells reproduce. Ask a Question How do chromosomes change and move during mitosis and meiosis? Materials pool noodles Safety Make Observations 1. Read and complete a lab safety form. 2. Form a cell nucleus with four chromosomes represented by students holding four different colors of noodles. Other students play the part of the nuclear membrane and form a circle around the chromosomes. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 3. The chromosomes duplicate during interphase. Each chromosome is joined by another chromosome of the same color, creating a double-stranded chromosome. 4. Perform mitosis. a. During prophase, the nuclear membrane breaks apart, and the nucleolus disappears. b. In metaphase, duplicated chromosomes align in the middle of the cell. c. The sister chromatids separate in anaphase. d. In telophase, the nuclear membrane reforms around two daughter cells. 5. Repeat steps 2 and 3. Perform meiosis. a. In prophase I, the nuclear membrane breaks apart, the nucleolus disappears, and homologous chromosomes pair up. b. In metaphase I, homologous chromosomes line up along the center of the cell. c. During anaphase I, the pairs of homologous chromosomes separate. d. In telophase I, the nuclear membrane reforms. e. Each daughter cell now performs meiosis II independently. In prophase II, the nuclear membrane breaks down, and the nucleolus disappears. f. During metaphase II, duplicated chromosomes align in the middle of the cell. Reproduction of Organisms 47 Name Date Class Lab B continued g. Sister chromatids separate in anaphase II. h. In telophase II, the nuclear membrane reforms. Form a Hypothesis 6. Use your observations to form a hypothesis about the results of an error in meiosis. For example, you might explain the results of an error during anaphase I. Remember to use scientific methods. Make Observations Ask a Question Form a Hypothesis Test your Hypothesis Analyze and Conclude Communicate Results Test Your Hypothesis 7. Perform meiosis, incorporating the error you chose in step 6. 8. Compare the outcome to your hypothesis. Does your data support your hypothesis? If not, revise your hypothesis and repeat steps 6–8. 9. Compare and Contrast How are mitosis and meiosis I similar? How are they different? 10. The Big Idea What is the difference between the chromosomes in cells at the beginning and the end of mitosis? At the beginning and end of meiosis? 11. Critique How did performing cellular replications using pool noodles help you understand mitosis and meiosis? 48 Reproduction of Organisms Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Analyze and Conclude Name Date Class Lab B continued Communicate Your Results Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Create a chart of the changes and movements of chromosomes in each of the steps in meiosis and mitosis. Include colored drawings of chromosomes and remember to draw the cell membranes. Extension Investigate some abnormalities that occur when mistakes are made during mitosis or meiosis. Draw a chart of the steps of reproduction showing how the mistake is made. Write a short description of the problems that result from the mistake. Lab Tips • Figure out where the boundaries of your cell are before you start. • Review the phases of mitosis and meiosis before beginning to act out how the chromosomes move during each process. Reproduction of Organisms 49 Name Date Class Lab C Cell Reproduction Directions: Use the information and data from the Lab Mitosis and Meiosis to perform this lab. You have acted out the moves that chromosomes make during mitosis and meiosis. This should help you understand the steps that occur when cells reproduce. Sometimes, during prophase I of meiosis, parts of homologous chromosomes might cross over each other and exchange sections of their chromatids. Crossing over results in new combinations of alleles that increase genetic diversity. Design a procedure similar to the original lab to model how crossing over occurs. You will need to replace the pool noodles with a material that can be cut or broken safely. Please note that you must complete Lab B before beginning Lab C. Have your teacher approve your design and safety procedures before beginning your experiment. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 50 Reproduction of Organisms
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