Apoptosis

anyone

anyone

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What exam board?
I think you are probably thinking above the level you need, biology a level seems to either go into so much detail or so very little that its frustrating...

Are you sure those two sentences are related. I'm not sure but it doesn't seem to me that the paragraph is relating the proton gradient and the proteins - just listing what happens.

In my book it says that nitric oxide can induce apoptosis by making the inner mitochondrial membrane more permeable to hydrogen ions and dissipating the proton gradient. Proteins are released into the cytosol. These proteins bind to apoptosis inhibitor proteins and allow the process to take place. I don't understand the last bit, does the proton gradient disappear and if it does how does this cause the proteins to be released and for apoptosis to occur? And also what are these proteins?

If the protons bind to the inhibitor proteins, they stop them from functioning. A bit like agglutanisation in immune defence. So apoptosis is no longer inhibited and can take place as the inhibitors can't act anymore. OCR F215?

I get that but I don't understand how making the cell membrane more permeable 'dissipates' the proton gradient, which I'm assuming they mean that it gets rid of the proton gradient. An yep it's F215.

The whole section is this:

The process is controlled by a diverse range of cell signals, some of which come from inside the cells and some from outside. The signals include cytokines made by cells of the immune system, hormones, growth factors and nitric oxide. nitric oxide can induce apoptosis by making the inner mitochondrial membrane more permeable to hydrogen ions and dissipating the proton gradient.

Proteins are released into the cytosol. These proteins bind to apoptosis inhibitor proteins and allow the process to take place.

If the membrane is more permeable then H+ can travel down the gradient from high conc to low conc regions. This means there is a smaller difference in H+ conc across the membrane.

That's what I can infer from what you wrote. I did the exam in January and last June too and I didn't really pay attention to it. I just learnt it the way I told you. Ask your teacher to be sure maybe or maybe someone else will explain. As it doesn't specify what type of membrane it is, I can't say much.

I thought you had an issue with the binding to inhibitor bit.

Ah thanks I get it now, that's the bit I didn't understand.