Explain what is Electron Transport Chain during respiration?

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vergil5203
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Explain what is Electron Transport Chain during respiration?

Post by vergil5203 » Wed May 09, 2007 6:32 am

Explain what is Electron Transport Chain during respiration?

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Post by david23 » Wed May 09, 2007 9:17 am

aaah havent i seen this somewhere else, many times.

ETC is on the inner mito membrane composed of several protein responsible for redox reactions where they carry electron starting from NADH for example, and ultimately reach an O2 molecule to make water. This is like a circuit, and the energy generated is used to make a proton gradient from the protons of NADH and FADH. The proton gradient is where the protons are pumped to the outside of the inner mito matrix. And as protons come back down the gradient, the energy is used to make ATP. Very simple right

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Post by SU_reptile » Wed May 09, 2007 2:54 pm

Very simple right

Too simple. I think it's vital to explain the role of particular electrone carriers in that process, but may be that's not the difficulty for vergil5203.
vergil5203 what is obscure for you in the electrone transport chain?? If you express it more accurately we will be able to give you full explanation.

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Post by vergil5203 » Fri May 11, 2007 2:23 am

However,the thing i really want is.how the electron transport chain worked with Krebs cycle. It because Krebs Cycle produce too many NADH so.i really want to know bout how the electron transport chain work with Krebs Cycle to produce plenty of ATP

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Post by SU_reptile » Fri May 11, 2007 8:04 am

In the TCA cycle there are three reactions that reduce NAD+ to NADH + H+ and one red-ox reaction with FAD giving FADH2. TCA enzymes work in the mitochondrial matrix, hence the dinucleotides produced there enter the ETC, which is abundant in the inner membrane, isn't it? NADH+H+ yields its electrones and protons (it's reoxidized) to the NADH+H+-ubiquinone dehydrogenase (complex I). Transport of NADH+H+'s electrones results in releasing protons to the intermembranal space - 3 times (it's done by three carriers/complexes 1st, 3rd, 4th).
FADH2, however yields its electrones to the 2nd carrier (complex II), thus it's entiled by only two pumping of protons to the intermembranal space, isn't it?
Protons load the H+ gradient across the inner membrane and that gradient is used by specialized complex of proteins, namely ATP-synthase (sometimes called complex V). The flow of 3 protons through it's rotor cause the production of 1 ATP molecule.
It's estimated that (re)oxidation of NADH+H+ in the ETC gives 2,5-3 ATP molecules, while FADH2 only 1,5-2 ones.
I hope it gives you any picture or sens of events accompaning ETC.

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