BIOL2117 Lecture 7: Mitosis
Document Summary
Dna has duplicated (chromosomes exist as sister chromatids) Sister chromatids are attached at centromeres (by cohesins) Chromosomes condense - shorter, fatter chromosomes are easier to segregate than longer ones. Condenses by the action of a ring-shaped protein complex called condesin - structurally related to cohesion rings that bind sister chromatids. Kinetochore assembly at the centromeres of sister chromatids. Kinetochore is a protein complex that include dyneins and kinesins one on each sister chromatid. Move things along the microtubules, so are motor proteins. There is one kinetochore assembled on each chromatid. Breakdown of nuclear envelope - in "open mitosis" Both envelope and lamina that sits below envelope. Some cells don"t undergo open mitosis - such as toxoplasma - but the nuclear envelope doesn"t break down. Process done by kinetochore microtubules or spindle microtubules - several of these microtubules. Kinesins walk toward plus end or kineticore end. Assemble at the minus (-) end of the tubules.
