BIOS 2011 Lab 2 Photosynthesis

It is called a coupling factor because it couples the

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Unformatted text preview: de the thylakoid is as much as 4 pH units lower than in the stroma. This pH difference across the membrane is known as the proton motive force (PMF) and is the driving power in ATP synthesis. Exercise 2 Photosynthesis In addition to pH difference, there is also a charge difference across the membrane. Because the primary electron acceptors are on the stromal side of the membrane, that side is more negative. Protons therefore "want" to flow into the stroma to offset this charge. The thylakoid membrane contains proton channels that take advantage of this tendency. The proton channel is part of a coupling factor, made up of CF1 and CF0 particles, which are very large proteins embedded in the membrane. It is called a coupling factor because it "couples" the electrochemical energy in the proton gradient with the phosphorylation of ADP + Pi (inorganic phosphate) to form ATP. CF1 spans the membrane and includes t...
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This note was uploaded on 02/09/2012 for the course BIOLOGY 102 taught by Professor Anderson during the Spring '11 term at Harvard.

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