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Chapter 11 Lecture and Reading Note taking Template Fill in this outline in lecture then use your textbook to add to it Notes from just the lecture are not enough to do well in this class Typical human epithelial cell in G2 of interphase would possess 46 replicated Division of a human somatic body cell undergoing mitotic cell division diploid cell chromosomes results in 2 diploid cells Human skin cell found to have 2 distinct nuclei each having 46 unreplicated chromosomes Observations would be seen in telophase in mitosis Substance is found to interfere with a dividing cell s ability to polymerize tubulin proteins into microtubules which phase would be interfered Formation of microtubule spindles Mitosis start with 1 diploid cell and ends with 2 Meiosis start with 1 diploid cell and ends with 4 haploid cells Gametes sperm and egg 1 What two processes does sexual life cycle include a Made up of meiosis and fertilization b Diploid cells i Somatic cells non reproductive body cells of adults have 2 sets of chromosomes Every cell that s not making sex cells c Haploid cells i Gametes have only one set of chromosomes 2 Define diploid cell and give an example Define haploid cell and give an example What are somatic cells What are germ line cells a drawing of Figure 11 2 to further explain 3 Explain the header sexual life cycles have both haploid and diploid stages Make your own 4 Why is meiosis critical in sexually reproducing organisms 5 What is the function of meiosis Section 11 2 Features of Meiosis 6 What are three features of meiosis name describe them Interphase in which germ line cells replicate DNA organelles etc a b Meiosis includes two rounds of division c Synapsis i During early prophase 1 ii Homologous chromosomes become closely associated 7 What is crossing over also referred to as recombination a What is it i Genetic recombination between nonsister chromatids ii Allows the homologous to exchange chromosomal material iii Introduces genetic variation b When does it occur i During metaphase 1 the paired homologues move to the metaphase plate Chapter 11 Lecture and Reading Note taking Template 1 In mitosis homologues behave indenpendently ii During anaphase1 c Why is it important i First meiotic division is terms reduction division 1 Results in daughter cells that contain one homologue from each chromosome pair ii No DNA replication between meiosis 1 and 2 iii Second meiotic division does not further reduce the number of chromosomes 1 Separates the sister chromatids for each homologue During metaphase I the paired homologues move to the metaphase plate and become oriented with homologues of each pair attached to opposite poles of the spindle In mitosis homologues behave independently During anaphase I homologues are pulled to opposite poles for each pair of chromosomes In mitosis sister chromatids are pulled to opposite poles 8 Why is the first round of meiosis referred to as reduction division Does DNA replication occur between Meiosis I and Meiosis II Why is this significant Second meiotic division does not further reduce the number of chromosomes Separates the sister chromatids for each homologue 9 Give a general overview of the phases of Meiosis I and II Fig 11 6 1 Meiosis 1 Prophase 1 2 Metaphase 1 chromosomes line up at metaphase plate 3 Anaphase 1 separation of homologous chromosomes 4 Telophase 1 chormosomes move to opposite ends of the cell 5 Meiosis 2 Prophase 2 6 Metaphase 2 7 Anaphase 2 8 Telophase 2 Bivalent four sister chromatids 10 Use Fig 11 4 to compare the alignment of chromosomes in meiosis I and mitosis 11 Orientation of each pair of homologues on the spindle is random Fig 11 5 Why is this significant 12 The independent assortment of maternal and paternal chromosomes occurs in Anaphase I Explain independent assortment 13 After meiosis I a How many cells 2 b Haploid or diploid Haploid c Duplicated chromosomes or not Yes Chapter 11 Lecture and Reading Note taking Template d Sister chromatids or not Yes e If sister chromatids Identical or not Not yet identical due to crossing over 14 What are the three sources of variation in meiosis a Crossing over during prophase 1 of meiosis b c Random fertilization the random combination of gametes from 2 different parents Independent assortment of chromosome pairs during anaphase 1 of meiosis 15 Meiosis II a Resembles a mitotic division b Prophase II nuclear envelopes dissolve and new spindle apparatus forms c Metaphase II chromosomes align on metaphase plate d Anaphase II sister chromatids are separated from each other e Telophase II nuclear envelope re forms around 4 sets of daughter chromosomes cytokinesis follows 16 What is the final result of meiosis a Four unique cells containing haploid sets of chromosomes b c In animals develop directly into gametes In plants fungi and many protists divide mitotically i Produce greater number of gametes ii Adults with varying numbers of gametes 17 Errors in meiosis occur by the process of and produce gametes Define both of these terms Nondisjunction failure of chromosomes to move to opposite poles during either meiotic division Aneuploid gametes gametes with missing of extra chromosomes 18 Meiosis is characterized by page 215 1 Synapsis and crossing over 2 Sister chromatids remain joined at their centromeres throughout meiosis 1 3 4 19 Be able to explain walk through Figure 11 7 Meiosis 1 Reduction state Prophase 1 A Chromosomes coil tighter and become visible nuclear envelope disappears spindle forms B Each chromosome composed of 2 sister chromatids C Synapsis i Crossing over occurs between nonsister chromatids ii Remain attached at chiasmata Metaphase 1 Chapter 11 Lecture and Reading Note taking Template A Microtubules from opposite poles attach to each homologous pair a Not each sister chromatid B Homologous are aligned at the metaphase plate C Orientation of chromosomes on the spindle is random Anaphase 1 together A Microtubules pull homologous chromosomes apart but sister chromatids are held B Orientation of each pair of homologous on the spindle is random leads to independent assortment of maternal and parental chromosomes C Homologues separate and move to opposite poles a Sister chromatids remain attached D Each pole has a complete haploid set of chromosomes consisting of one member of each homologous pair E Independent assortment Telophase 1 A Nuclear envelope re forms B Sister chromatids are no longer identical because of crossing over C Cytokinesis may or may not occur


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SDSU BIOL 151 - Chapter 11

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