Unit: Equilibrium in Aqueous Solution Module: Buffers [page 1 of 1]
An Introduction to Buffers
• The human body is a complex system of buffers. Without buffers the macroscopic
characteristics of proteins would break down.
Buffers are composed of a weak acid and its conjugate base.
• Calculations for buffer systems are acid-dissociation constant (K ) aroblems.
The human body contains many complex systems
involving proteins with various side chains. Among
these are carboxylic acid groups and amino groups
In an equilibrium between acetic acid and ammonia,
a proton can be transferred from the acetic acid to
the amino group.
At a blood pH of 7.5, the carboxylic acid groups are
deprotonated. Also, the amino groups are
protonated (fig. 2). These charged groups help hold
proteins together and are responsible for much of
the macroscopic structure of proteins. If the blood
pH were to drop significantly below 7.5, the
carboxylic acid groups would be protonated and the
amino groups would be deprotonated. The entire
structure of proteins in the blood would break down.
Buffers are composed of a weak acid (HA) and a