Second test notes

Second test notes - 1 Reproduction 1 2 types of cell...

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1. Reproduction 1. 2 types of cell division used my most euks 1. Mitosis occurs when cell makes a copy of cell 1. Functions in growth and cell replacement 2. Meiosis provides gametes for sexual reproduction 3. Cells reproduce by duplicating chromosomes and partitioning them and organelles between 2 daughter cells 4. Most euk cells have pairs of chromosomes = diploid 1. Human cells have 23 pairs 2. One of each pair is from mom, one from dad 3. Pair members have similar structures and are called homologs 4. Gametes are haploid (sperm, egg, etc) 2. Life cycle of a cell 1. {DIAGRAM FROM LECTURE} 2. Interphase-chromosomes are diploid; not visible 1. Our 46 chromosomes are replicated in S phase to produce 92 sister chromatids 1. Sisters remain attached at centromere 1. = construction on pair of chromatids 2. # of chromosomes always = # of centromeres 3. Have a kinetochore that microtubules attach to 3. Mitosis 1. Begins when chromosomes become visible 2. 4 stages: PMAT 1. Prophase 1. Chromosomes become highly condensed 2. Transcription stops; nucleolus disappears 1. In animals, centrioles move to opposite poles 3. Nuclear envelope breaks down so microtubules can get to chromosomes 1. Microtubules form spindle apparatus and attach kinetochores 2. Metaphase 1. Chromatids are lined up in the center of cell by microtubules 1. Called the metaphase plate 2. Near the end of metaphase, centromeres divide, freeing sister chromatids 3. Anaphase 1. Shortest: a few minutes 2. Microtubules pull sisters to opposite poles and push against poles to stretch cells 4. Telophase 1. Returns cell to interphase 2. Chromosomes uncoil 3. Transcription begins again 4. Spindle apparatus is dissembled
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5. Envelope forms around each new nucleus 6. Cytokinesis - physical division of cell into two parts after telophase 1. By contraction of belt of actin/myosin filaments which forms a cleavage furrow (in cells without walls) 2. Plants build a new cell membrane and wall between daughters 4. Meiosis 1. Provides gametes for sexual reproduction 2. Fusion of haploid gametes produces a new diploid cell 1. = fertilization or syngamy 2. Sexual reproduction provides genetic variability for selection to operate on 1. Offspring aren’t exact copies because they carry traits from both parents 5. Mitosis vs. meiosis 1. Mitosis and meiosis begin the same with chromosome duplication in interphase 2. PMAT stages in Meiosis I are called P1, M1, A1, and T1 3. In mitosis, duplicated homologous chromosomes line up individually along the metaphase plate 4. In meiosis I, duplicated homologous chromosomes pair during P1 and stay paired along meta plate during M1 5. In anaphase of mitosis, each chromatid of a homolog is pulled to a diff pole 6. In anaphase I of meiosis, each homolog pair is pulled to a diff pole 7. In humans, meiosis I produces two new cells with 23 chromosomes/centromeres 1. Each chromosome is 2 attached sister chromatids 8. Meiosis II performs mitosis on cells produced by meiosis I 9. Pairing of homologs in P1 =
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This note was uploaded on 02/10/2011 for the course BIO 1500 taught by Professor Maruniak during the Fall '08 term at Missouri (Mizzou).

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Second test notes - 1 Reproduction 1 2 types of cell...

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