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14. Describe at least two ways meiosis I and meiosis II are different?Mitosis and Meiosis
During meiosis 1 homologous chromosomes separate, while during meiosis 2, sister chromatids separate. Meiosis 1 only produces two diploid daughter cells, while meiosis 2creates 4 diploid daughter cells. 15. How does crossing over affect the genetic content in the daughter cells? When pieces of chromosomes are exchanged between non-sister chromatids during crossing over, it creates genetic diversity by creating new combinations that did not originally present in the parent cells. 16. How many chromosomes were present in the cell when meiosis I started in your pipecleaner experiment?There were four total X-shaped pipe cleaner chromosomes.17. How many cells are present at the end of meiosis II in your experiment? How many chromosomes are present in each cell?There are four gamete daughter cells at the end of meiosis 2, with two chromatids present in each cell (two pieces of different colored pipe cleaners, no longer in an X shape after meiosis 2).18. What are two ways that meiosis contributes to genetic recombination?Through the exchange of chromosome segments during crossing over, meiosis allows for new combinations of chromosomes in the daughter cells that were not present in the parent cells, which creates genetic diversity. In addition, chromatids remain attached but homologous pairs separate during meiosis 1, which means that the daughter cells have the same chance of receiving either homologous chromosome. In our diagram it would have been either the red chromosome or the orange chromosome. The fact that one daughter cell would have the red, while the other would have the orange would create genetic diversity as well. Similar randomization also happens during the anaphase in meiosis 2 when the centromeres dissolve, because it is random which chromatids will bepassed onto which daughter cell.Mitosis and Meiosis
19. Why is it necessary to reduce the number of chromosomes in gametes, but not in other cells? Gametes are sex/reproductive cells, so since they require fertilization, if the amount of chromosomes has to be halved because if that were not the case we would have doublethe amount of chromosomes. We get half of our chromosomes from the egg cell and the other half from the sperm cell.20. Elephants have 56 chromosomes in every cell. Determine how many chromosomes you would expect to find in the following:a.Sperm Cell: male gamete = half the total, so 28b.Egg Cell: female gamete = half the total, so 28 againc.Daughter Cell from Mitosis: mitosis is a “clone” of the original cell, so it would have the same total amount of 56d.Daughter Cell from Meiosis II: after meiosis 2, the number in the gamete daughter is the same as half of that of the parent cell, so 28 again21. Research and find a disease that is caused by chromosomal mutations. When does the mutation occur? What chromosomes are affected? What are the consequences?