 Another place where we find a buffer solution to try and maintain a consistent pH are in cells and particularly in the cytoplasm of cells. These are looking at a pH of around 7.2, so slightly lower than the pH of the blood but still nonetheless pretty close to what we would regard as neutral. The problem in cells of course is there are lots and lots of proteins and proteins have a three dimensional structure which affects their function and any changes in this three dimensional structure can actually inhibit the function of the proteins. So therefore and one of the things that can affect that well there's two main things that can affect that other than other chemicals and that is temperature, if the temperature gets too high or too low and also pH. So change in pH can affect proteins and therefore can affect their function. So again it's very important that any additional hydrogen ions or reduction in hydrogen ions are counted as quickly as possible and as effectively as possible so that the pH of the cytoplasm doesn't change too drastically and affect these proteins. Again biologists are probably aware of the fact that if the change is too significant the proteins may denature and once that happens they won't reform their original shape and therefore they become useless. This is a dihydrogen phosphate ion you can kind of tell by looking at it that it's anti-protech it can either gain or lose a proton and it's in equilibrium with the hydrogen phosphate or bifosphate ion and it's the buffer that we have or that we find in cells in the cytoplasm of cells. Once again the same thing happening what we want to do is use our Le Chatelier's principle to say if there is an increase in the concentration of H plus ions the system is going to shift in order to try and counter that bring it back down to bring it down it would have to shift to the left and therefore we'd also have a drop in the concentration of the hydrogen phosphate ion and an increase in the concentration of the dihydrogen phosphate ions. So you can see buffers are bringing together our understanding of acid-base reactions and blending it with what we've also been looking at in the first topic on equilibrium and acid reactions. So this is kind of a nice place to leave this module where we've got that application of both our understanding of acids and bases and equilibrium as we look forward to our next module which is an organic chemistry. Good luck with the acid-base reactions hopefully you can even find a couple more examples of buffers in natural systems that you can use to explain how they try and maintain a consistent pH and thanks for watching.