Photolysis and Photosynthesis-please help

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Bexstar
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Photolysis and Photosynthesis-please help

Post by Bexstar » Sun Oct 29, 2006 4:50 pm

i am completing a piece of a level coursework into the effect of temperature on photosynthesis. i know that at high temperatures the enzymes involved in photosynthesis are denatured, but how does the dentaured enzymes affect light dependent stage/dependent stage/photolysis and does this cause a change in pH?

SOMEONE PLEASEEEEEE HELP ME AS I AM GETTING DESPERATE AND ONLY HAVE 24 HOURS LEFT TO COMPLETE THIS C/W.

Becky

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Post by Bexstar » Mon Oct 30, 2006 1:03 pm

please can some one help me as i have inyl a few hours left and am very confused????

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MrMistery
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Post by MrMistery » Tue Oct 31, 2006 10:03 am

well, ya know, the water splitting complex dows involve enzymes...
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dipjyoti
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Post by dipjyoti » Tue Oct 31, 2006 10:08 am

Temperature influences photosynthesis primarily via enzyme activity- as temperature increases, rate goes up (until proteins denature)
rate of temperature increase (aka Q10) for photorespiration is greater than photosynthesis; thus at high temperatures photorespiration becomes more of a problem for C3 plants.


Low temperatures (> freezing) influence both enzyme activity and “fluidity” of chloroplast membrane- increase the potential for photoinhibition.

Most plants have enzyme systems and membrane structure that are well matched to the temperature range they experience.

pH of what?

Thanx!!!

Dip Jyoti Chakraborty

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MrMistery
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Post by MrMistery » Tue Oct 31, 2006 10:24 am

i think he is referring to the fact that the pH of the thylakoid lumen decreases greatly when the photochemical reactions pump protons from the stroma into the thylakoid lumen. thus the pH of both compartiments chnges. if the membrane fluidity is decreased and the enzyme activity is low, the pumping of protons will slow down all the way to them stopping...
"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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