assignment HW

Pre-Lab Questions What are chromosomes made of? Chromosomes are made up of protein and a single molecule of DNA. Compare and contrast mitosis and meiosis. (At least 2 similarities & 2 differences) Both mitosis and meiosis begin with a single parent cell which eventually splits to form new daughter cells. They both go through all the same steps of cell replication but meiosis goes through two steps while mitosis one has to go through one during each step. And both end at cytokinesis! Mitoses is used to replicate body cells and replace others while meiosis is “breaking down” a cell to its smallest form and becoming a sex gamete. That is where meiosis I and meiosis II come into play. In mitosis there is 2 diploids created and in meiosis there are 4 haploid daughter cells created. With this the 2 diploid cells they are identical cells whereas the haploid cells are genetically different. How does mitosis differ in plant cells versus animal cells? The difference is in the cytokinesis stage where the two daughter’s cells divide. For the animal’s cells a cleavage furrow cell separates the cells. Whereas the plant cells have a plant cell that separates the cell. Cancer is a disease related to uncontrolled cell division. Investigate two known causes for cancer and state what they are. Research a cancer treatment drug and give a brief description of how this drug works as a treatment. One of the known causes for cancer is smoking. An individual can get many different types of cancer from it. Lung cancer, throat cancer, tongue cancer just to name a few. Then there is melanoma cancer. You can get that directly from the sun or from going to a tanning bed. Another can be due to a lifestyle you have, be it poor diet, alcohol, obesity, or sheer bad luck of genetics. R-CVP is a cancer treatment drug. It stands for a combination of drugs, R – rituximab (Mabthera), a targeted cancer drug C – cyclophosphamide, a chemotherapy drug V – vincristine, a chemotherapy drug P – prednisolone, a steroid It destroys quickly dividing cells Experiment 1: Observation of Mitosis in a Plant Cell Data Tables Table 1: Mitosis Predictions Predictions Supporting Evidence Table 2: Mitosis Data Image Stage Number of Cells in Stage Total Number of Cells Calculated % of Time Spent in Stage Interphase Prophase Metaphase Anaphase Telophase Cytokinesis Table 3: Stage Drawings Cell Stage Drawing Interphase Prophase Metaphase Anaphase Telophase Cytokinesis Post-Lab Questions Label the arrows in the slide image with the appropriate stage of the cell cycle. A _ B _ C _ D _ E _ F_ In what stage were most of the onion root tip cells? Does this make sense? As a cell grows, what happens to its surface area-to-volume ratio (hint: think of a balloon being blown up)? How does this ratio change with respect to cell division? What would happen if mitosis were uncontrolled? How accurate were your time predictions for each stage of the cell cycle? Discuss one observation you found interesting while looking at the onion root tip cells. Experiment 2: Following Chromosomal DNA Movement Through Mitosis Cell Cycle Division: Mitosis Beads Diagram 57150059753500 left237299500 Post-Lab Questions (Experiment 2) Why are chromosomes important? What information do they contain? Chromosomes are important because that is where our DNA is stored. Chromosomes contain most, if not all the genetic information of an organism. How many chromosomes did each of your daughter cells contain? Every daughter cell contains 23 chromosomes from each parent 46 in total. How often do human skin cells divide? Compare this rate to how frequently human neurons divide. Is there a difference? Why might that be? A human skin cell will divide daily. It is our outer most protection, so to remain up to par, it will replicate and replace daily to protect us. It also has a short cycle which means it goes through mitosis often. Neurons spend decades in interphase verses dividing. Describe the mitotic spindle. What is its function? What composes it? A mitotic spindle is made up of microtubules made out of cytoskeleton proteins. A spindle originated from the centrosomes which are at each end of a cell. The function of a spindle is to create a “highway” to move chromosomes as the cells divide. Experiment 3: Following Chromosomal DNA Movement Through Meiosis Cell Cycle Division: Part 1 – Meiotic Bead Diagrams (Without Crossing Over) Cell Cycle Division: Part 2 – Meiotic Bead Diagrams (With Crossing Over) Post-Lab Questions (Experiment 3) What is the state of DNA at the end of meiosis I? What about at the end of meiosis II? At the end of meiosis I there is 2 diploid cells with the same amount of DNA as the parent cells. At the end of the meiosis II phases there will be haploid chromosome sets, or 4 daughter cells from the parent cells in total. How are meiosis I and meiosis II different? In meiosis one there's crossing over or recombination of genetics while in meiosis two there is not. Why do you use non-sister chromatids to demonstrate crossing over? Because sister chromatids are identical so there will be no changing the daughter nuclei if both were the same. What combination of alleles could result from a crossover between BD and bd chromosomes? You may get a Bd or a bD. How many nuclei are present at the end of meiosis II? How many chromosomes are in each? There will be four nuclei and two chromosomes in each. Identify two ways that meiosis contributes to genetic recombination. Why is genetic recombination important in sexual reproduction? It ensures genetic diversity by an assortment of homologous chromosomes and crossing over process. During sexual reproduction the crossing over creates gametes that contains new combinations of genes which helps generate a large genetic diversity of an offspring resulting in the eventual union of two gametes. Why is it necessary to reduce the number of chromosomes in gametes? Meiosis create cells that are destined to become gametes otherwise during fertilization offspring would result in twice the normal number of chromosomes. Blue whales have 44 chromosomes in every cell. Determine how many chromosomes you would expect to find in the following: Sperm Cell you would have 22 chromosomes Egg Cell you would have 22 chromosomes Daughter Cell from Mitosis with mitosis being the normal cell division you would end up with 44 chromosomes Daughter Cell from Meiosis II since meiosis is the reduction of chromosomes your daughter cells would end up going down to 22 chromosomes Research and find a disease that is caused by chromosomal mutations. When does the mutation occur? What chromosomes are affected? What are the consequences? A chromosomal mutation can be color blindness. It’s a mutation in the 23rd X chromosomes and passed during fetal development. Usually it is the Red/green colors that are not seen or are incorrect but some others may be effected as well. Experiment 4: Crossing Over Data Tables Table 4: Sodaria fimicola Crossover Data Image Number of Crossovers Number of Non-Crossovers Image 1     Image 2     Image 3     Post-Lab Questions Determine the percentage of crossovers. To do this, divide the number of crossovers by the total number, and multiply it by 100. Determine the map distance. To do this, divide the percentage of crossover by two. Note that the number is divided by two because crossover occurs once between two chromosomes. Experiment 5: The Importance of Cell Cycle Control Data 1. 2. 3. 4. 5. Post-Lab Questions Record your hypothesis from Step 1 here. What do your results indicate about cell cycle control? Suppose a person developed a mutation in a somatic cell that diminishes the performance of the cell’s natural cell cycle control proteins. This mutation resulted in cancer but was effectively treated. Is it possible for this person’s future children to inherit this cancer-causing mutation? Why or why not? Why do cells that lack cell cycle control exhibit karyotypes that look physically different than cells with normal cell cycle control? What are HeLa cells? Why are HeLa cells appropriate for this experiment? Research the function of the protein p53. Explain how changes in p53 activity may affect cell cycle control. What is the Philadelphia chromosome? How is this chromosome related to cancer? Identify how this chromosome appears physically different on a karyotype than it appears on a karyotype of normal chromosomes.