Oxidative phosphorylation HO

Inux of these 10 h through atp synthase powers the

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Unformatted text preview: chain, the amount of ATP synthesised by a molecule of NADH or FADH2 oxidised can be calculated. This stoichiometric relaBonship is known as the P/O ra&o ie. the amount of ATP synthesised (P) to the amount of oxygen reduced (O). 6 1/04/11 The P/O ra&o The transfer of a pair of electrons through Complexes I, III and IV results in the efflux of 10 H+ across the inner mitochondrial membrane. Influx of these 10 H+ through ATP synthase powers the producBon of 2.5 ATP. How many ATP would you esEmate are produced from a molecule of FADH2? Coupling The electron transport chain and oxidaBve phosphorylaBon (H+ gradient ­dependent synthesis of ATP) are Bghtly coupled. This coupling relies on the impermeability of the inner mitochondial membrane. 7 1/04/11 Coupling In a resBng state, oxidaBve phosphorylaBon is minimal. The electrochemical gradient increases, inhibiBng the electron transport chain. H+ can reenter the mitochondrial matrix via ATP synthase. When ATP synthesis occurs, the gradient dissipates and electron transport conBnues. Uncouplers •  An uncoupler increases the permeability of the inner mitochondrial membrane to H+. •  This uncouples oxidaBve phosphorylaBon from the electron transport chain as dissipaBon of the H+ occurs by a means other than ATP synthesis. 8 1/04/11 Uncouplers 2,4 ­dinitrophenol (DNP) is an uncoupler that was used in the 1920 s as a diet pill. As the energy of the H+ gradient was lost as heat and the body needed to metabolise more CHO and fat reserves to yield ATP. Could too m...
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This document was uploaded on 02/27/2014 for the course BIOC 2201 at University of New South Wales.

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