Biological molecules and buffer?

Question

is phosphate buffer a "good" buffer to use in a biomedical science laboratory?how much effect 1M of HCl has on the pH of a phosphate buffer and why is this important for buffer function?

Answer 1

Phosphate is a common, maybe the most common, buffer in medical research labs.  It's a good buffer: not terribly expensive, easy to make and control, not very corrosive, and 'natural'.   The effect of adding HCl will depend on the concentration of the buffer, but yes, because phosphate is tribasic, it will be less of an effect than it might be for other buffer choices.   The function of a buffer is to resist pH changes when acid or base is added.  This enhances that function, so is important.  Why?  Well because you used the buffer initially because you had a reason for wanting pH to stay at some value.  Whatever your reason was for doing that, that's the importance of it.

Answer 2

A phosphate buffer is good in the sense that it's pKa is quite similar to that of your bicarbonate buffer in your blood system.  Adding small amounts of strong acid or base to any buffer solution will cause the pH to increase or decrease very little (in your case, decrease).  You need a buffer in your blood so you don't die a very painful death if you somehow had too much hydrogen ion present in your bloodstream (since blood operates normally only between 7.35-7.45 pH)

[Answer: see above]