C4 and photorespiration


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C4 and photorespiration

Post by freaky001 » Sun Sep 14, 2008 6:38 pm

can i know how does C4 plants minimizes the photorespiration?i do understand its pathway but not sure how it reduces photorespiration..

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Post by MrMistery » Wed Sep 24, 2008 2:25 am

c4 plants have a special leaf anatomy that reduces the contact between the Rubisco enzyme and molecular oxygen. This is done by an accesory fixation pathway: the enzyme PEP carboxylase first fixes CO2 onto Phosphoenolpyruvate(PEP) to give phosphate and oxaloacetate which is then reduced to malate in the mesophyll cell. then the malate goes to the bundle sheath cell, where it is "broken down" back to CO2. the CO2 can then be fixed by Rubisco with minimum photorespiration, because there is not that much oxygen in the bundle sheath cells.

"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter

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