4 protein kinases can be dephosphorylated by protein

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Unformatted text preview: s can be dephosphorylated by protein phosphatases. 8. What are the differences between chloroplast photophosphorylation and mitochondrial oxidative phosphorylation in terms of original electron donor, ultimate electron acceptor, energy input, and subcellular/suborganellar localization? Mitochondrial oxidative Chloroplast phosphorylation photophosphorylation Original e donor NADH or FADH2 H2O Ultimate e acceptor Oxygen NADP+ Energy input NADH photons Subcellular/suborgnellar Inter membrane of Thylakoid membrane; + locations mitochondria; [H ] high [H+] high in lumen of in intermembrane space thylaoid membrane sac and low in matrix; ATP and low in stroma produced in matrix (matrix); ATP and NADPH produced in stroma 6 9. If water labeled with 18O is added to a suspension of photosynthesizing chloroplasts, which of the following compounds will first become labeled with 18 O: ATP, NADPH, O2, or 3PGA (3-phosphoglyceric acid which can be reduced to form G3P [GAP])? If water labeled with 3H is added to a suspension of photosynthesizing chloroplasts, which of the same compounds will first become labeled with 3H? If CO2 labeled with 14C is added, which of the same compounds will first become labeled with 14C? 18 O first shows up in O2. 3H first shows up in NADPH. 14C first shows up in 3 PGA (3-phosphoglyceric acid or 3-phosphoglycerate or glycerate 3 phosphate [though the last version is rarely used]. 10. What is the expected reaction catalyzed by rubisco (RuBP carboxylase)? What are its problems? What modifications of photosynthesis could alleviate most of these problems? Rubisco (RuBP carboxylase) catalyzes the carboxylation of ribulose 1,5bisphosphate (RuBP) converting it to two molecules of 3 PG (3phosphoglyceric acid) that are then reduced to form the simplest sugar, glyceralhehyde 3 phosphate (G3P). However, rubisco can also reacts with oxygen that is quite abundant in air (20%) causing the breakdown of RuBP to form a C2 compound plus a 3PG. Two of these C2 compounds are then condensed to form a C3 compound and release a CO2. This wasteful process i...
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This note was uploaded on 01/26/2014 for the course BIO 2960 taught by Professor Hafer during the Spring '12 term at University of Illinois, Urbana Champaign.

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