2009 Exam 2

G enetic m icrobiological a nd geologic evidence a ll

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Unformatted text preview: 4 p ts. G enetic, m icrobiological, a nd geologic evidence a ll p oint to a sequence of e v e n ts in th e e v o lu tio n o f b a c ter ia th a t lea d to th e d e v e lo p m e n t o f a e ro b ic r e sp ira tio n in m o d ern eu k ary o tes. F o u r of the se e v en ts are listed b elow – N U M B E R t hem e a ch i n o rde r, w ith 1 b e in g th e e a rlies t ev e n t an d 4 b e in g th e late st: order (1, 2, 3 or 4) EVE NTS A b a c ter iu m , en g u lfe d in a sta b le f a sh io n b y a e u c a ry o tic c e ll, transferred m ost o f its geno m e to the eucaryotic cell n u cleus. 4 P h o to sy n th e tic b a c ter ia p ro d u c e d O 2 fo r > 1 0 9 y e a rs, fin a lly oxidizing all o ceanic Fe2 + a nd then changing the earth’s a tm os phere 2 M a in life f o rm s w e re a n a e ro b ic b a c ter ia th a t ex p lo ited a b io tic carbon s ources and ex creted o rganic acids. 1 In a n u trien t- a n d O 2 -ric h e n v iro n m e n t, so m e b a c ter ia lo st th e ir ability to photos ynthesize and becam e specialized for respiration 3 (b ) 2...
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This note was uploaded on 03/12/2012 for the course BIO 231 taught by Professor Hollenbeck during the Fall '11 term at Purdue.

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