Question

1. Explain why the HCO3VCO2 buffering system is so effective in controlling the pH of the extracellular solution. Include in your answer the role of haemoglobin in buffering of the H+ ions derived from CO2 in the blood.

Please give a detailed explanation. Add supportive equations if possible.

Answer 1

The HCO3/CO2 buffering system helps in controlling the pH of the extracellular solution and it is an important extracellular buffer. This is because when a strong acid is added to the bicarbonate solution, it helps in converting the bicarbonate (HCO3) into carbonic acid which is H2CO3. The carbonic acid after its formation can dehydrate and it leads to the formation of water (H20) and carbon dioxide (CO2). The hemoglobin plays an important role in buffering the H+ ions which is obtained from CO2 in blood and it act as a good buffer as it has the tendency to bind to the H+ ions. The hemoglobin is able to accept the H+ as it consists of the basic amino acid histidine. When high level of CO2 is present, the hemoglobin is able to bind and accept the H+ and as it does so, it acts as buffer and helps in maintaining the homeostasis of the body and hence prevent causing huge change in pH of the body.