Beknopte samenvatting van H12 mitosis

H12. Mitosis
Inhoudsopgave

Verdeling chromosomen ................................................................................................................................ 2

Celcyclus ........................................................................................................................................................ 2

Binaire splitsing .............................................................................................................................................. 4

, Verdeling chromosomen
1: interfase = duplicatie ter preparatie van celdeling
2: mitose = gekopierd en naar buitenkant gebracht
3: cytokinese = cel splits in 2 dochtercellen
Figure 12.5_3
1 Chromosomes Chromosomal
DNA molecules
Centromere


Chromosome
arm
Chromosome duplication

2




Sister
chromatids
Separation of sister
chromatids
3 Celcyclus

Figure 12.6

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S
G1
(DNA synthesis)



s
si
ne
ki G2
is




to
s




Cy
ito
M




• G1: celgroei (door toename cytoplasma)(extra eiwitten, nucleotiden & chromatine komt
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vrij)
• S: chromosomen verdubbelen
• G2: controle + herstel van het nieuwe DNA (aanmaak histonen -> chromatine te kunnen
spiraliseren)(verdubbeling centriolenpaar)
• G0: rustfase (cellen die niet meer delen) (soms gaan ze toch nog naar G1)
• Mitose: kerndeling
• Cytokinese: cytoplasma deling

, Figure 12.7a




10 µm
G2 of Interphase Prophase Prometaphase
Centrosomes Chromosomes Early mitotic Fragments Nonkinetochore
(with centriole (duplicated, Aster of nuclear
spindle microtubules
pairs) uncondensed) Centromere envelope




Plasma
Nucleolus Two sister chromatids Kinetochore Kinetochore
Nuclear membrane
of one chromosome microtubules
Figure 12.7b envelope
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10 µm


Metaphase Anaphase Telophase and Cytokinesis
Metaphase Cleavage Nucleolus
plate furrow forming




Daughter
chromosomes
Spindle Nuclear
Centrosome at envelope
one spindle pole forming
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Profase:
• Chromatine è chromosomen
• Vorming spoelfig. (Trekdraden (=kinetochoren) & steundraden)
• Trekdraden hechten aan centromeer

Metafase:
• Chromosomen -> max. gecondenseerd
• Liggen in evenaarsvlak

Anafase:
• Trekdraden korter
• Zusterchromatiden gescheiden è naar polen

Telofase:
• Spoelfiguur weg
• Chromosomen despiraliseren & decondenseren è chromatinevezels
• Nieuwe kernmembranen & nucleoli

Cytokinese:
• Insnoering cel (ring van actine- & myosinevezels)