IPHY%3060%Lecture%#13%“%Tour%de%organelle”%Text%pgs%15+26,%487+502%Key%points%of%today’s%lecture%%1)%%Eukaryo;c%cells%are%divided%up%into%mul;ple%compartments%%%%%%(sub+cellular%organelles).%4)%%Mul;ple%mechanisms%have%evolved%to%get%proteins%into%%%%%%different%cellular%compartments%5)%%Proteins%have%“address%sequences”%that%serve%to%direct%%%%%%%them%to%specific%compartments.%3)%%Some%organelles%were%likely%“acquired”%rather%%%%%%%than%evolved%from%scratch.%2)%%Organelles%are%membrane+bound%subcompartments%%%%%%of%cells.%%%?%Lynn%Margulis%the%“Endosymbiont”%%Hypothesis%Cells%today%The%Endosymbiont%hypothesis%–%mitochondria%and%chloroplasts%originated%from%symbioIc %bacteria%What%evidence%would%support%the%%Endosymbiont%Hypothesis?%SpoNed%salamander%SymboIc%algae%are%inside%cells%of%developing%salamander%tadpoles%MulIple%membraneObound%organelles%in%EukaryoIc%cells%What%good%are%organelles?%Model%for%formaIon%of%“nonOacquired”%organelles%Cell%membranes%are%composed%of%a%lipid%bilayer%Can%proteins%go%through%membranes?%“Fear%of%water”%is%a%major%force%driving%protein%folding%cellular%ribosomes%Everything%“white”%is%topologically%outside%of%the%%cytoplasm%EukaryoIc%cellular%ribosomes%are%in%the%cytoplasm%How%do%proteins%get%into%organelles?%(and%how%do%they%know%which%ones%to%go%into?)%There%are%mulIple%mechanisms%to%get%proteins%into%organelles%Nuclear%pore%complex e s%se en%under%electron%micr osc ope%Nuclear%import%is%a%specific,%acI ve%process%for%large%molecule s%(mRNA%export%involves%a%transport%receptor%opera;ng%in%the%opposite%direc;on)%Fusion%of%cell%vesicles%is%like%bubble%fusion%But%not%as%preNy%computa;onal%model%Although%membrane%fusion%does%not%require%energy,%specific%%proteins%are%needed%to%direct%membrane%fusion%to%the%right%place%nucleus%“rough”%ER%Ribosomes%associate%with%the%endoplasmic%reIculum,%and%synthesize%proteins%that%are%translocated%
View Full Document
Unlocking...