Cell Division Flashcards
what forces produce stabilisation necessary for correct attach,ents?
Kinetochore poleward
MT flux - small amount of fluorescent tubulin added, MTs gave speckles under microscope and using time lapse photography we see poleward speckle moevemnt.
Polar ejection force
What is the structure of dynein?
minus end directed, links plus ends of astral MTs to components of actin cytoskeleton and cell cortex
pulls spindle poles towards cell cortex and away from each other.
How do opposing forces cooperate to move chromosomes to metaphase plate?
Polar ejection force created by kinesins 4 and 10 - pushes chromosomes toward spindle equator.
Poleward forces (depolymerisation at kinetochore and MT flux pull chromosomes toward pole).
What experimetns support the astral relaxation model?
Treat C elegans early embryos to lose astral MTs
Increased contractile activity through cell cortex observed.
What can go wrong with cytokinesis on cancer?
It can fail –> binucleated cells
These cells begin division
Centrosomes are duplicated (2 nuclei each make own spindle)
Multipolar mitosis –> failure and DNA damage which destabilises chromosomes and may lead to cancer.
Describe interpolar microtubules.
antiparallel array of MTs in midzone - cross linked in middle giving spindle stucture!
What happens to micro tubules in metaphase and prometaphase?
Half life decreases and centrist me activity increases
Dense and dynamic arrays of MTs form to capture sister chromatids
