Chemiosmotic Theory

[SarCaustic]

Hello,

Over the last 2 weeks in we've been studying respiration in my A level biology class. Basically, the Oxidative Phosphorylation stage is quite vague in our notes and our teacher told us that's all that was on the syllabus. She also told us the Chemiosmotic Theory would explain what happens in more detail - so here I am. Can someone explain what the theory is?

Thanks in advance.

[A Chill Wind]

Where was Wikipedia when I was at school?

http://en.wikipedia.org/wiki/Chemiosmosis

[Peter Pedant]

Jesus, I had to learn Mitchell's theory in 1973 and I am glad to see that it hasnt changed much.

It is q hard to learn and or it doesnt make much sense.

The wikipedia article is more than you need for A level
I suppose the salient points are:

1.no high energy intermediate identified
2.concentration differences are associated with energy levels (straightforward thermodynamics)
3.There is a spatial arrangement of the proteins - or else they dont work (because they have to be across the conc gradient)

er and that's about it.

there's an ABer who was asking about endobiotic theory - see the last sentence of the wikipedia article - he may be able to help

[Peter Pedant]

More modern biologists can help

but the thing that Mitchell really got people thinking is that he identified purple bacteria as pumping H+ one way through the membrane and he sort of patched in part of a membrane where the protein pumped it the opposite way

and Mitchell basically said - yippee I have made a [proton pump] cycle !

and everyone agreed that wow like it was just crazy and would account for ATP generation

He did get a Nobel prize 15 years later which is kinda quick for these things - by contrast the cardiologist who described the Z disc in cardiac muscle got a prize in around 1975 and did his work on Z discs in yes 1906 - he was 92