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Compare and contrast mitosis and meiosis.




On your own and without assistance, complete this Lab 5 Answer Sheet;electronically and submit it via the Assignments Folder by the date listed in the;Course Schedule (under Syllabus).;To conduct your laboratory exercises, use the Laboratory Manual located;under Course Content. Read the introduction and the directions for each;exercise/experiment carefully before completing the exercises/experiments and;answering the questions.;Save your Lab 5 Answer Sheet in the following format: LastName_Lab5;(e.g., Smith_Lab5).;You should submit your document as a Word (.doc or.docx) or Rich Text;Format (.rtf) file for best compatibility.;eScience Labs, LLC 2014;Pre-Lab Questions;1. Compare and contrast mitosis and meiosis.;Both mitosis and meiosis are involved with the dividing of cells and the splitting of;DNA between the new cells that are made. They can also be parts of reproduction.;In meiosis I, tetrad form and crossing over occurs during prophase I. This does not;occur during mitosis. In metaphase I of meiosis, tetrads align at the spindle equator.;The paired chromosomes have a total of four chromatids each. In mitosis, dyads;align at the spindle equator. During meiosis two nuclear divisions are required but in;mitosis only one nuclear division required.;Mitosis is the process, in the cell cycle, by which the chromosomes in the cell;nucleus are separated into two identical sets of chromosomes. Mitosis immediately;followed by cytokinesis resulting in two daughter cells crating two diploid cells that;are genetically the same to each other and the parent crating two diploid cells.;Meiosis produces four daughter divisions and four daughter cells which results in;four haploid cells with half the chromosome number as the parent cell. During;meiosis there is crossing over of the DNA which means that the DNA on;two different chromosomes can mix to create genetic diversity. This is why the;daughter cells are genetically not the same to each other and to the parent.;2. What major event occurs during interphase?;During interphase, the cell duplicates it DNA. The cell does most of its growing in;this stage. This phase also produces the components needed for cell division.;Interphase consists of three phases: one synthesis phase and two gap phases.;During early interphase the G1 (gap) stage growth occurs and in the late interphase;(the G2 stage). DNA replication takes place during mid-interphase the S (synthesis);stage.;eScience Labs, LLC 2014;Experiment 1: Following Chromosomal DNA Movement;through Meiosis;Data Tables and Post-Lab Assessment;Trial 1 - Meiotic Division Beads Diagram;Prophase I;Metaphase I;Anaphase I;Telophase I;Prophase II;Metaphase II;Anaphase II;eScience Labs, LLC 2014;Telophase I;Cytokinesis;Trial 2 - Meiotic Division Beads Diagram;Prophase I;Metaphase I;Anaphase I;Telophase I;Prophase II;Metaphase II;Anaphase II;eScience Labs, LLC 2014;Telophase I;Cytokinesis;Post-Lab Questions;1. Poloidy of the DNA at What is the the end of meiosis I? What about at the end of;meiosis II?;Meiosis I is the reductional division because it halves the number of chromosome;sets per cell - a reduction from two sets (the diploid state) to one set (the haploid;state). The sister chromatids then separate during the second meiotic division;meiosis II, producing haploid daughter cells.;2. How are meiosis I and meiosis II different?;At the end of meiosis I, both of the resulting daughter cells are haploid (definitely not;diploid). However, the chromosomes are still double-stranded. The homologous;pairs have already been separated. In humans, this means that the original cell had;23 pairs of chromosomes, and the cells at the end of meiosis I have 23;chromosomes (not pairs), each of which still have two sister chromatids. At the end;of meiosis II, there are a total of four daughter cells, each of which is diploid. At this;point, the sister chromatids have separated from each other. In humans, this means;that these gametes each have 23 chromosomes, each of which has one chromatid.;3. Why do you use non-sister chromatids to demonstrate crossing over?;Crossing over occurs between homologous chromosomes, which are not identical;as one member of each pair of homologous chromosomes comes from the mother;and one member comes from the father. Sister chromatids are identical and crossing;over would have no effect.;4.;What combinations of alleles could result from a crossover between BD and;bd chromosomes?;eScience Labs, LLC 2014;5. How many chromosomes were present when meiosis I started?;There are 46 chromosomes at the beginning of meiosis I.;6. How many nuclei are present at the end of meiosis II? How many chromosomes;are in each?;There are 4 nuclei and there are 2 chromosomes in each.;7. Identify two ways that meiosis contributes to genetic recombination.;Crossing over during prophase I, corresponding segments of non-sister chromatids are;exchanged and independent assortment of homologous chromosomes.;8. Why is it necessary to reduce the number of chromosomes in gametes, but not in;other cells?;Gametes have fewer chromosomes then other cells so that the offspring has the same;amount of chromosomes as the parents;9.;Blue whales have 44 chromosomes in every cell. Determine how many;chromosomes you would expect to find in the following;i.;Sperm Cell: 22;i.;Egg Cell: 22;iii.;Daughter Cell from Mitosis: 44;iv.;Daughter Cell from Meiosis II: 22;10.;Research and find a disease that is caused by chromosomal mutations.;When does the mutation occur? What chromosomes are affected? What are the;consequences?;eScience Labs, LLC 2014;The human body has 23 pairs of chromosomes: 22 pairs of autosomes and 1 pair of sex;chromosomes. This gives humans 46 chromosomes in total. Chromosomal genetic;disorders occur when chromosomes are partially or completely missing, altered or;duplicated. An example of a chromosomal genetic disorder is Down syndrome. Down;syndrome is the result of an extra, third copy of chromosome 21 being present in a;person. This extra chromosome results in extra protein production and upsets the bodys;balanced systems. During pregnancy chromosomal abnormalities can cause the death;of an embryo or fetus. Chromosomal disorders can result in mental retardation or other;developmental problems. Older pregnant women have a higher risk of passing on;chromosomal genetic disorders.;11.;Diagram what would happen if sexual reproduction took place for four;generations using diploid (2n) cells.;Experiment 2: The Importance of Cell Cycle Control;Data Tables and Post-Lab Assessment;1.;2.;3.;4.;5.;Post-Lab Questions;1.;Record your hypothesis from Step 1 in the Procedure section here.;I might observe if all the chromosomes are normal except for one added chromosomes;then there will be an abnormality in the cell and it will shape different from the rest.;eScience Labs, LLC 2014;2.;What do your results indicate about cell cycle control?;3.;Suppose a person developed a mutation in a somatic cell which diminishes;the performance of the bodys natural cell cycle control proteins. This mutation;resulted in cancer, but was effectively treated with a cocktail of cancer-fighting;techniques. Is it possible for this persons future children to inherit this cancercausing mutation? Be specific when you explain why or why not.;4.;Why do cells which lack cell cycle control exhibit karyotypes which look;physically different than cells with normal cell cycle.;5.;What are HeLa cells? Why are HeLa cells appropriate for this experiment?;eScience Labs, LLC 2014


Paper#15294 | Written in 18-Jul-2015

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