Lecture 14 � Chemiosmosis, Fermentation, Anaerobic Respiration

Lecture 14 � Chemiosmosis, Fermentation, Anaerobic Respiration

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Unformatted text preview: Lecture 14 Chemiosmosis, Fermentation, Anaerobic Respiration 1. Chemiosmosis mechanism of oxidation phosphorylation 2. Chemosmotic mechanism (figs. 8.9, 8-10) Chemical and transport Chemical meaning protons Transport of the protons across the cristae membrane Ele c tro n tr a n s p or t c h ai n Co m pl e x 1 is a pr ot o n p u m p fro m t h e m a t rix int o t h e Int er m e m b r a n e s p a c e , t his is a c tr a n s p or t b e c a u s e pr o t o n s a r e b ei n g p u m p e d a cr o s s t o a r e gio n of hi g h e r c o n c e n t r a ti Co m pl e x 2 is n o t a pr o t o n p u m p Co m pl e x 3 is a pr ot o n p u m p Co m pl e x 4 is al s o a pr o t o n p u m p NADH g o e s t o all t h e c o m pl ex e s , FADH2 g o e s t o o n e ( 2) Ele c troc h e mi c al g r a di e n t (pro t o n-m o tiv e forc e) It is el e c tric a n d c h e mic al, t h e Int er m e m b r a n e s p a c e is m o r e p o sitiv e t h a n t h e m a t rix Th e Int er m e m b r a n e s p a c e h a s a pH of 4 , t h e m a t rix h a s a pH of 8 pH r e pr e s e n t s t h e c h e mic al, c h a r g e r e pr e s e n t s t h e el e c tric w h e n e v e r yo u h a v e a g r a di e n t, it c a n b e u s e d t o d o w ork, s u c h a s m a ki n g ATP ATP s y n t h a s e (co m pl e x 5 ) Co n sid er e d a c h a n n el pr o t ei n Lollypo p la m e e e Pa s siv e tr a n s p or t, let s t h e pr o t o n s t hr o u g h wit h t h eir c o n c e n t r a tio n g r a di e n t Wh e n pr ot o n s a r e let t hr o u g h , ATP is m a d e Th e y d o n't k n ow h o w m a n y pr o t o n s, b u t for e v e r y NADH y o u g e t a m a xi m u m of 3 ATP ( 2. 7) For e v e r y FADH2, yo u g e t a m a xi m u m of 2 ATP In glyc olysis, NADH n e e d s t o b e s h u t tl e d t o t h e cris t a e m e m b r a n e Mos t of o ur ( m u s cl e s) c ells, w h e n y o u s h u t tl e t h e el e c tro n s, e n e r g y is los t t ur nin g NAD t o FADH2; e n e r g y is n o t los t in t h e h e a r t m u s cl e 3. Maximu m ATP yield a. Glucose oxidation Glycolysis 2 ATP from substrate level phosphor ylation 2 NADH, (in m ost cells, x2, in hear t x3; anywhere from 46 ATP depending on shut tle) Formation of Acetyl CoA 2 NADH (x3, which leaves 6) Kreb's Cycle 2 ATP, substrate level, 6 NADH x 3 18 2 FADH2 x2 Total ATP yield for glucose oxidation is 3638 4. Fermentation (fig. 813) Ethanol Lactic Acid 5. Anaerobic Respiration ...
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This note was uploaded on 05/30/2008 for the course BS 131 taught by Professor Smith during the Spring '08 term at University of the Sciences in Philadelphia.

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