TAMU BIMS 320 - BIMS 320 Textbook Questions and Problems

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BIMS 320 Textbook Questions and ProblemsCH. 1 A Perspective on Human Genetics1. Summarize Mendel’s conclusions about traits and how they are passed from generation togeneration.Genes are passed from parent to offspring.- Each parent carries two genes that control a trait- Each parent contributes one copy from each pair- Pairs of genes separate from each other during the formation of egg and sperm (meiosis)- When egg and sperm fuse during fertilization, genes from mother and father become a new gene pair2. What is population genetics?The study of processes that influence gene distribution in populations- Identifies how much genetic variation exists in populations by investigating factors that change the frequency of a specific gene over time (i.e., migration, population size, natural selection)3. What is hereditarianism, and what is the invalid assumption it makes?4. What impact has recombinant DNA technology had on genetics and society?5. What are genomes?The complete set of genetic information we all carry 6. What is genomics?The study of the entire genome of an organism7. In what way has biotechnology had an impact on agriculture in the United States?8. We each carry 20,000 genes in our genome. Genes can be patented, and over 6,000 human genes have been patented. Do you think that companies or individuals should be able to patent human genes? Why or why not?9. If your father were diagnosed with an inherited disease that develops around the age of 50, would you want to be tested to find out whether you would develop this disease? If so, when would you want to be tested? As a teenager or sometime in your 40s? If not, would you have children?CH. 2 Cells and Cell DivisionCell Structure Reflects Function1. What advantages are there in having the interior of the cell divided into a number of compartments such as the nucleus, the ER, lysosomes, and so forth?2. Assign a function(s) to the following cellular structures:a. plasma membrane – regulates the exchange of materials between the inside and outside of the cellb. mitochondrion – site of cellular respiration and ATP productionc. nucleus – contains the genetic information necessary to control cell structure and functiond. ribosome – aid in the production of proteins on the RER and ribosome complexes (polysomes)3. How many autosomes are present in a body cell of a human being? In a gamete?There are 44 autosomes in a body (somatic) cell and 22 autosomes in a gamete4. Define the following terms:a. Chromosome – the threadlike structures in the nucleus that carry genetic informationb. Chromatin – the DNA and protein components of chromosomes5. Human haploid gametes (sperm and eggs) contain:a. 46 chromosomes, 46 chromatidsb. 46 chromosomes, 23 chromatidsc. 23 chromosomes, 46 chromatidsd. 23 chromosomes, 23 chromatidsThe Cell Cycle Describes the Life History of a Cell6. What are sister chromatids?Chromatids joined together by a centromere7. Draw the cell cycle. What is meant by the term cycle in the cell cycle? What is happeningat the S phase and the M phase?Cells undergo a series of events involving growth, DNA replication, and division that are repeated by the daughter cells forming a cycle, called the cell cycle. During the S phase, DNA synthesis occurs. During the M phase, mitosis and cytokinesis take place.8. In the cell cycle, at which stages do two chromatids make up one chromosome?a. beginning of mitosisb. end of G1c. beginning of Sd. end of mitosise. beginning of G29. Does the cell cycle refer to mitosis as well as meiosis?Yes10. It is possible that an alternative mechanism for generating germ cells could have evolved.Consider meiosis in a germ cell precursor (a cell that is diploid but will go on to make gametes). If the S phase were skipped, which meiotic division (meiosis I or meiosis II) would no longer be required?Meiosis II, the division responsible for the separation of sister chromatids, would no longer be necessary. Meiosis I, wherein homologues segregate, would still be required. 11. Identify the stages of mitosis, and describe the important events that occur during each stage.Prophase: Chromosomes become visible as threadlike structures. As they continue to condense, they are seen as double structures with sister chromatids joined at a single centromereMetaphase: all chromosomes have become lined up at the equator of the cell Anaphase: centromeres divide, and chromosomes move toward opposite polesTelophase: chromosomes decondense; nuclear membrane forms12. Why is cell furrowing important in cell division? If cytokinesis did not occur, what wouldbe the end result?It allows the cells to divide into two so if it did not happen then the cell would not divide and could cause disease13. A cell from a human female has just undergone mitosis. For unknown reasons, the centromere of chromosome 7 failed to divide. Describe the chromosomal contents of the daughter cells. 14. During which phases of the mitotic cycle would the terms chromosome and chromatid refer to identical structures?Prophase15. Describe the critical events of mitosis that are responsible for ensuring that each daughtercell receives a full set of chromosomes from the parent cell.Mitosis Is Essential for Growth and Cell Replacement16. Mitosis occurs daily in a human being. What type of cells do humans need to produce in large quantities on a daily basis?Blood cells, skin cells17. Speculate on how the Hayflick limit may lead to genetic disorders such as progeria and Werner syndrome. How is this related to cell division?A lack of cell divisions below the hayflick limit can lead to premature aging as seen in these disorders18. How can errors in the cell cycle lead to cancer in humans?Cell-cycle gene products regulate the process of cell division. If a gene normally promotes cell division, mutant alleles can cause too much cell division. If a gene normally turns off cell division, mutant alleles may no longer repress cell division. Each of these errors in cell cycle regulation may lead to the uncontrolled cell divisions characteristic of cancer.Cell Division by Meiosis: The Basis of Sex19. List the differences between mitosis and meiosis in the following chart:Attribute Mitosis Meiosis# daughter cells produced 2 4# chromosomes per daughter cell2n nDo chromosomes pair? No YesDoes crossing over occur? No YesCan the daughter cells Yes Nodivide again?Do the chromosomes replicate before division?Yes YesType of cell produce Somatic Gamete_____20. In the


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TAMU BIMS 320 - BIMS 320 Textbook Questions and Problems

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