Interphase. Chapter 10 Notes. Objective 1: Summarize the events that occur during mitosis

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1 Chapter 10 Notes Ratio of Surface Area to Volume i Cells 10 1 Cell Growth A. Limits to Cell Growth 1. DNA Overload 2. Exchagig Materials 3. Ratio of Surface Area to Volume 4. Cell Divisio Cell Size Surface Area (legth x width x 6) Volume (legth x width x height) Ratio of Surface Area to Volume 10 2 Cell Divisio A. Chromosomes B. The Cell Cycle C. Evets of the Cell Cycle D. Mitosis 1. Prophase Aaphase 4. Telophase E. Cytokiesis Objective 1: Summarize the evets that occur durig mitosis Homologous chromosome--a member of a chromosome pair. similar i shape, size, ad the gees they carry. Chromatid--oe of a pair of strads of DNA that make up a chromosome durig meiosis or mitosis. Figure 10 4 The Cell Cycle Iterphase M phase G 1 phase S phase This is the o-reproducig stage of a cell s life. It is the logest stage of a cell s life Major evets i iterphase: Cells grow durig iterphase Chromosomes are duplicated about mid-way through iterphase to prepare for mitosis. G 2 phase 1

2 Iterphase Aimal Cell Plat Cell Prophase Major evets i prophase: Nucleoli disitegrates Chromati coils up to form chromosomes Cetrioles move to opposite poles of the cell Microtubules form spidle fibers betwee the cetrioles The ucleus breaks dow Prophase Aimal Cell Plat Cell Major evets i metaphase: Chromosomes attach to the spidle fibers at the cetromere Chromosomes move to the equator of the cell Aimal Cell Plat Cell Aaphase Major evets i aaphase: Cetromeres split The two sister chromatids separate ad move apart to opposite poles of the cell 2

3 Aaphase Aimal Cell Plat Cell Telophase Major evets i telophase: The ucleoli reappear The ucleus reforms Chromosomes ucoil ad appear as a mass of chromati Cytokiesis Major Evets: Happes at the same time as telophase I aimals: cell membrae piches i at the ceter I plats: a cell plate forms at the equator of the cell Daughter cells are formed Telophase& Cytokiesis Aimal Cell Plat Cell Sectio 10-2 Figure 10 5 Mitosis ad Cytokiesis Sectio 10-2 Figure 10 5 Mitosis ad Cytokiesis Cetrioles Spidle formig Cetrioles Spidle formig Nuclear evelope reformig Nuclear Chromati Cetromere evelope Iterphase Prophase Cytokiesis Idividual Aaphase Cetriole Spidle Cetriole Nuclear evelope reformig Nuclear Chromati Cetromere evelope Iterphase Prophase Cytokiesis Idividual Aaphase Cetriole Spidle Cetriole Sectio: Sectio: 3

4 Sectio 10-2 Figure 10 5 Mitosis ad Cytokiesis Sectio 10-2 Figure 10 5 Mitosis ad Cytokiesis Cetrioles Spidle formig Cetrioles Spidle formig Nuclear evelope reformig Nuclear Chromati Cetromere evelope Iterphase Prophase Cytokiesis Idividual Aaphase Cetriole Spidle Cetriole Nuclear evelope reformig Nuclear Chromati Cetromere evelope Iterphase Prophase Cytokiesis Idividual Aaphase Cetriole Spidle Cetriole Sectio: Sectio: Sectio 10-2 Figure 10 5 Mitosis ad Cytokiesis Sectio 10-2 Figure 10 5 Mitosis ad Cytokiesis Cetrioles Spidle formig Cetrioles Spidle formig Nuclear evelope reformig Nuclear Chromati Cetromere evelope Iterphase Prophase Cytokiesis Idividual Aaphase Cetriole Spidle Cetriole Nuclear evelope reformig Nuclear Chromati Cetromere evelope Iterphase Prophase Cytokiesis Idividual Aaphase Cetriole Spidle Cetriole Sectio: Sectio: --a form of cell divisio that halves the umber of chromosomes whe formig reproductive cells. Mitosis vs I Prophase I Chromosomes become visible Nuclear evelope breaks dow Crossig-over occurs I Pairs of homologous chromosomes move to the equator of the cell 4

5 I Aaphase I Homologous chromosomes move to opposite poles of the cell Telophase I ad Cytokiesis Chromosomes gather at the poles of the cell Cytoplasm divides II Prophase II A ew spidle forms aroud the chromosomes II Chromosomes lie up at the equator II Aaphase II Cetromeres divide Chromatids (ow called chromosomes) move to opposite poles of the cell. Telophase II ad Cytokiesis Nuclear evelope forms aroud each set of chromosomes Cytoplasm divides Prophase I I X X Close-up View X X Bivalet Cetromere N N N N Daughter Cells of meiosis II Chiasma (site of crossig-over) Bivalets alig at the metaphase plate Sister chromatids remai together durig aaphase I Mitosis vs. 2 = 4 Daughter Cells of meiosis I No further chromosomal replicatio; sister chromatids separate durig aaphase II Mitosis Chromosomes alig at the metaphase plate Sister chromatids separate durig aaphase x x Prophase 2N 2N Daughter Cells Mitosis See if you ca idetify the stages of prophase, metaphase, aaphase, ad telophase. Notice that mitosis results i two diploid daughter cells. You should be able to idetify each stage of mitosis as it appears whe viewed with a light microscope. To see mitosis i a plat cell, click here. To see mitosis i a aimal cell click here. See if you ca idetify meiosis I ad meiosis II ad the stages of prophase, metaphase, aaphase, ad telophase withi each meiotic divisio. Notice that meiosis results i four haploid daughter cells. To see what the stages of meiosis look like through a microscope click o the followig liks. Click here for meiosis I. To see meiosis II, click here. 5

6 Objective 2: Relate crossig-over, idepedet assortmet, ad radom fertilizatio to geetic variatio. Idepedet assortmet--the radom distributio of homologous chromosomes. Crossig-over--the exchage of reciprocal segmets of DNA by homologous chromosomes at the begiig of meiosis. Fertilizatio is the radom joiig of 2 gametes. Importace of Geetic Variatio ad the joiig of gametes geerates variatio more quickly tha ay other geetic process. Geetic variatio is essetial to evolutio. Size icrease i domesticated aimals The ability to produce larger ad larger aimals slows dow as existig geetic combiatios are used up. Racehorse breedig Times i races stopped improvig decades ago. Objective 3: Compare the formatio of gametes i male & female aimals Spermatogeesis--the process by which sperm are produced i male aimals. Occurs i the testes Oogeesis--the process by which gametes are produced i female aimals. Occurs i the ovaries Gamete Developmet Diploid germ cell Diploid germ cell Spermatogeesis Oogeesis Sperm cell Egg cell Polar bodies i male & female aimals Sperm Formatio I II Udifferetiated sperm cells Diploid germ cell Immature sperm cells Egg Formatio Secodary egg cell First polar body Udifferetiated egg cell Secod polar bodies (all 3 will die) Objective 4: Differetiate betwee asexual ad sexual reproductio asexual reproductio--a sigle paret passes copies of all of its gees to each of its offsprig There is o fusio of haploid cells The offsprig is a cloeof its paret sexual reproductio--two parets each form haploid reproductive cells, which joi to form offsprig. Sperm Egg cell (ovum) 6

7 Objective 5: Idetify three types of asexual reproductio Fissio--separatio of a paret ito two or more idividuals of about equal size. Fragmetatio--the body of a orgaism breaks ito several pieces. fragmets develop ito adults whe missig parts are regrow Buddig--ew idividuals split off from existig oes. Objective 6: Evaluate the advatages ad disadvatages of asexual ad sexual reproductio Asexual Reproductio Advatages produce may offsprig i short period of time do t waste eergy makig gametes or lookig for a mate Disadvatages little geetic variatio betwee idividuals Sexual Reproductio Advatages quickly produce differet combiatios of gees amog idividuals Disadvatages produce fewer offsprig i loger periods of time waste eergy makig gametes & lookig for a mate Objective 7: Differetiate betwee the three major sexual life cycles foud i eukaryotes Life cycle--the etire life spa of a orgaism from oe geeratio to the ext. Haploid life cycle Haploid cycle simplest of sexual life cycles haploid cells occupy the major portios of the life cycle zygote is the oly diploid cell zygote udergoes meiosis after it is formed haploid cells give rise to multicellular idividuals multicellular idividuals produce gametes through mitosis (ot meiosis) Fusio--gametes fuse to produce a diploid zygote Haploid life cycle 2 Zygote Fusio Haploid Idividual Mitosis Diploid life cycle Diploid cycle adult idividuals are diploid i most aimals, a diploid reproductive cell udergoes meiosis to produce gametes fertilizatio--gametes joi to produce a diploid zygote diploid idividual occupies the major portio of the life cycle 7

8 Diploid life cycle Reproductive cell 2 Diploid Idividual 2 2 Zygote Fertilizatio Gametes Alteratio of geeratios Sporophyte--the diploid phase i the life cycle that produces spores Spore--a haploid reproductive cell produced by meiosis that is capable of developig ito a adult without fusig with aother cell. Alteratio of geeratios Gametophyte--haploid phase that produces gametes by mitosis. gametes fuse ad give rise to the diploid phase Alteratio of geeratios Sporeformig cell 2 Sporophyte 2 Gametophytes 2 Zygote Fertilizatio Mitosis Where to go for more Corell Uiversity has a olie tutorial that will allow you test your kowledge of mitosis ad meiosis. I recommed that you give the questios a try. To do so, just click here. The Uiversity of Arizoa also has a olie quiz over the stages of mitosis. If you wat to test yourself at idetifyig the various stages of mitosis, click here. The meiosis tutorial for the Uiversity of Arizoa ca be foud by clickig here. More pictures of meiosis here. A mitosis olie quiz. Click here. A meiosis olie quiz. Click here. 8