Naturally occurring acid base buffering system in an organism

[aisha]

I tried looking for this online, but didn't really find anything can someone help me out I need an example of a naturally- occurring acid-base buffering system in an organism

 

[rhuthwaite]

We have a natural acid base buffering system within us. The normal pH of our blood is about 7.40. If our blood falls outside of the 7.35 to 7.45 range we would become seriously ill. Digestion produces a range of products, a lot of them are acidic and despite this addition of H+ ions the blood pH is maintained. This is done through H/CO3 -/H2CO3 buffers in red blood cells and the blood plasma.
HPO4 2-/H2PO4 - are also used as buffers in maintaining constant PH in cells and urine

 

[siddharth]

To add to what rhtuhwaite said, you may want to visit these sites for more information.

http://www.chemistry.wustl.edu/~edudev/LabTutorials/Buffer/Buffer.html
http://www.brynmawr.edu/Acads/Chem/Chem104lc/buffers.html

 

[aisha]

I think I am having trouble because I have two questions that are quite similar

The first question was
Which macromolecule within the body can act as a buffer?

I wrote the following

The macromolecules within the body that can act as a buffer are proteins. Proteins are effective buffers inside cells and blood. They are the most important buffers in the body. The most active protein buffer within the blood is hemoglobin. It absorbs excess hydrogen ions when it’s not carrying oxygen. Another macromolecule that acts as a buffer is the phosphate buffer. Its concentration is low in the extracellular fluid, however it is an important urinary and cytoplasm buffer. Finally, there is a bicarbonate buffer system within the body that can be found in tissue fluids and blood.

The next question was
Find another example of a naturally-occurring acid-base buffering system that exists within an organism.

I feel like this is the same question is it?