Answer to Question #4067 in Biochemistry for fadzai

Question

Explain how CO[sub]2[/sub] is buffered in the blood causing stabilization of blood Ph.

Answer 1

CO₂ itself is an inert substance and does not change pH. However, in blood, CO₂ reacts with water and forms carbonic acid (H₂CO₃). This acid dissociates (to H⁺ and HCO₃^-) and can lower blood pH, but there are 4 buffering systems, that work simultaneously and prevent blood pH from changing. The systems are called bicarbonate, phosphate, haemoglobin and protein buffering systems. This systems have acceptors of protons (such
as COO^- groups of proteins and haemoglobin, HCO₃^- and (NaHPO₄)^2- ions) which react with proton that is created when CO₂ dissolves in blood, so the proton is neutralized. Thus, the amount of protons is stable and
blood pH does not change.