por Rainier Ababao 11 anos atrás
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Assist E. coli in folding proteins correctly
Needed for powering cellular work by making ATP
Couples exergonic reactions with endergonic reactions e.g. Glutamic acid + ammonia -> glutamine ('tis endergonic, nonspontaneous) Glutamic acid + ATP -> Phosphorylated intermediate + ADP -> Glutamine + ADP + Pi (got coupled, so 'tis exergonic, thus spontaneous)
In the bundle-sheath cell, the 4C compound releases CO2 which is reassimilated into the carbon cycle with rubisco and the normal players of the Calvin cycle. The same reaction regenerates pyruvate.
Pyruvate is converted to PEP by ATP. The ATP is the price of concentrating CO2 in the bundle-sheath cells. To make extra ATP, bundle-sheath cells carry out cyclic electron flow. There is no PS II in bundle-sheath cells so PS I, which carries out cyclic electron flow, is their only photosynthetic mode of generating ATP.