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8. Cicle cel:lular: fases. La mitosi. Cromosomes metafásics. Control del cicle cel-lular. Al microscopi es veu només una part del cicle Es pot distingir: - Interfase: tot igual - Mitosi: canvis importants Consultar informació i imatges tema del nueli Totes les cél-lules estan dins d'un cicle vital la “immortalitat” de les cellules Es pot detectar la síntes1 d'ADN cells in Gr phase number of cells. cells in Gzand M phases AS, -Timidina-H -Br-dU (análog de T) 0 1 2 relative amount of DNA per cell Vorbitrary units) - Análisi de ADN/cellula Cito8.Histo T-08 1/11 Les fases del cicle cellular La fase M té varles etapes CYTOKINESIS SPHase [DNA replcation) ani embryonie celicyte SETA AE Citocinesi — divisió de célula (citoplasma) La mitosi en una cel-lula animal La mitosi en una cel:lula vegetal Ominutes (8) 15 evírutes. (C) 17 minutes (D) 54 minutes (E) 89 minutes 0 E 20 pen Fragmoplast: tabic central per fusió de vesícules del complex de Golgi | Citog8Histo T-08 2/11 trogmentso nuclear omvolopo tinercnore As prophoss, the repliatad chromosome, each consisting of two closely associated sister chromatids, condense. Outside the nucleus, the mitoticspindie assembles setween the two. centrosomes, which have repli- catod and moved apart For implicty, only tree chromosomes are shown. ln «liploid cell, there wouid bo two copies of each chromosome úbrupti vet tha breakalown of ho nuclear anvolopo. Chromonomsa ¡can now attach to spindio me =79 min [Bl TeLoPHase set of dougier chromosome a indi pote contacte ring arg o tor nuca envelopo reossembling round individual vomosormes During teloph sets of deu! somos arrive attho poles of the spindle and decondense. Anew nuclear envelope. roassembles around esch set, completng tho formation. TB] cYroxiNesis completed nuclear envetope During cytotinesis, the. vtoplasm is divided in wo by a contracil ring of actin and myosin flaments, vmich pinches. the coll two to create two daughters, each vih “one nucleus (ormation of interphaso of mistorubues nucleated BB merapnase canon Kinetochoro mcrorabalo Atmetaphaso, the ehromosomes are alignad attho equator ofthe spindle, midway between the spindio ¿oles. The rinetochore microtubules. y chromatidato olas oftho. TES lauhtor chnomosomos tw toward he spíndle pole it aces. The Kinetochore microtubales get sh "ume = 279 min Els cromosomes estan molt empaquetats VS 10) DNA cla y condi Més informació: tema del nueli Cito8.Histo T-08 4/11 Els cromosomes i els microtúbuls Els cromosomes i el cinetocor replicated chromosome centromere region of chromosome kinetochore kinotochore microtubules [iaa chromatid El cinetocor s”uneix específicament als A Metafase 1 anafase: la coordinació microtúbuls AN, Wins y Tots els cromosomes al centre Les cromátides se separen y 1 (6) puma] CitogHisto T-08 5/11 Els motors del fus mitótic OUTWARD PUSH ON SPINDLEPOLES-— plus-end-directed motor protein / > astral - overlap microtubules microtubules Ñ ) + minus-end-directed a motor protein (050550050 OUTWARD PULL ÓN SPINDLE POLES CEE La citocinesi 1 els microfilaments remaining overtap microtubules. from central spindio me] myosin filaments in cleavage furtow. 200 um L”Anafase: AiB Cromosomes Fus mitótic Altres models de mitosi SAL DMOAAGELLAtES Cito8.Histo T-08 71 El cicle cel:lular té un control 0208 in vivo kE = in vitro Les ciclines controlen el cicle cellular ls all DNA replicated? Are all chromosome ls environment favorcble? attached to tho spndlo? eyelin Ga CHECKPOINT METAPHASE CHECKPOINT ESA a W cyclin- dependent kinase (Cdk) Gs CHECKPOINT Hi ha un control molecular del cicle cel-lular ls orvironmontavorable? Quinasa: enzim que fosforila % 2 vice bo LS maso Marta ie phosphatase cor CÁk activating phosphate [2 [2 CC AETIVE INACTIVE CitogHisto T-08 8/11 Efecte de les caspases en la cel-lula IN pe bulo 728 mesy motecues ct active casper Y IORANIAN ln ln ln —- 
