Zoology Exam 2

Zoology Exam 2 - ZoologyExam2...

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Zoology Exam 2 03:53 All cells come from pre-existing cells Cell Division     -cell reproduction      =copy DNA, separate DNA In Eukaryotes: Meiosis leads to production of gametes Mitosis leads to production of other cell types somatic cells In prokaryotes: Binary fission Mitosis (mitosis/cytokinesis) Parent cell   daughter cell Daughter are identical to parent cell and each other Functions of Mitosis 1.Growth + Development 2.Repair + Replacement  scrape knee   mitosis fixes cells 3.Asexual Reproduction ex: yeast unicellular function Chromosome Structure carrying genetic material 46 chromosomes (humans) 23 pairs  of chromosomes
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each species has a characteristic number of chromosomes any organism/cell paired chromosome = Diploid (2n) how would you describe yourself? 2n=46   diploid with 46 chromosomes 2n cell   two 2n cells each chromosome is replicated prior to mitosis Sister Chromatids Replicated chromosomes Original and its copy Chromosomes become tighter so organized and easy to separate during mitosis  Centromere  Region where sister chromatids attach Site of kinetochore formation Kinetochore Protein structure on chromosome where microtubules can attach Microtubules (MTs) Built from tublin- can build or break down The Cell Cycle Cells alternative between: Dividing phase (mitotic) Non-dividing phase (interphase)
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G1 S G2 m phase Ex: start with diploid cell 2n=4 (at G0) Cell gets signal to divide, goes into G 1  = cell growth S phase = DNA is replicated (only time DNA is replicated) G 2 phase  = cell growth, centrosomes appear and then double Centrosome  = microtubule organizing center M phase  (4 stages) –doc. Camera notes Late interphase cell 2n=4 1. Prophase preparing for separation of DNA nuclear envelope disappears chromosomes condense chromosomes migrate to opposite poles of the cell mitotic spindles forms microtubules (MTs) + associated proteins grow from centrosome some MTs attach to kinetochore kinetochore microtubles
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non kinetochore microtubles  2. Metaphase chromosomes line up on the metaphase plate centromeres are ON the metaphase plate sister chromatids are on each side of metaphase plate 3. Anaphase separation of sister chromatids  kinetochore MTs shorten (tubulin subunits removed) pull sister chromatids apart at the centromeres non kinetochore MTs get longer (adding tubulin subunits) causes cell to enlongate motor proteins are important cause non kinetochore MTs to shift relative to each other so cell elongates how do microtubules move chromosomes during mitosis? Kinetochore MTs shorten during anaphase due to loss of tubulin subunits at the…
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This note was uploaded on 03/06/2012 for the course ZOO 101 taught by Professor Sharon during the Fall '08 term at Wisconsin.

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Zoology Exam 2 - ZoologyExam2...

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