Question

What does a buffer have to do with respect to each of these ions in order to control the pH within the cell?

Answer 1

A buffer is a solution which is supposed to resist the change in pH of the environment. A buffer has both positive and negative counter ions, to balance both drop or rise in pH. When the pH of solution becomes acidic, which implies an increase in concentration of hydride ions, the buffer should release the negatively charged conjugate base. This neutralizes the drop in pH. Similarly, when pH becomes basic, more hydroxide ions are released in solution, the buffer then releases more of the positively charged conjugate acid, to neutralize the pH.