BIOL 303 Lecture Notes - Lecture 9: Spindle Apparatus, Cleavage Furrow, Cell Cycle
27 Apr 2016
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All externally developing animals (sea urch, c. eleg) are under enormous pressure to dev fast wanna be motile, protected, fuly func as adult asap. Unfertil egg: cyclinb mrna cannot be translated, its bound to maskin (binds cyclin b mrna and prevents translation). Once ca wave, maskin is targeted for degredation, cyclin b is free to bind cdk. S8 isolethical (iso= same, yolk is evently distr thruout egg) Meso= yolky vegetal side (asym, giving polarity to early eggs) ex amphibians. Telo: denser yolk thruout cell = ex chicken. Have bilateral cleavage : make a disk of incomplete cell divisions on top of a very thick yolk. Discoidal cleagave (ex zebra fish) = incomplete cleavages. Centro: yolk in middle (ex insects) syncitial cell division (incomplete) Mitotic spindle (orient the direction that chrsm pull apart , the center of where chrms are pull apart, is wehre cleavage furrow forms = so how u orient mitotic spindle, determines orientation of cell divison.
