Buffering agents and buffer solutions are present in many different systems. It can appear in the field of agriculture as Monopotassium phosphate (MKP) to reduce nitrogen loss in fertiliser while prividing source of potassium while avoiding pH fluctuations. Your daily shampoo are also buffered to act on soap’s alkalinity. You won’t want either to be overly acidic or alkaline if you treasure your skin and hair. More importantly it can also appear in biological system.
Part 14 of Berry Berry Easy notes on Ionic Equilibrium for STPM Chemistry (Kimia) is on buffer solution in biological systems. In this post, Berry Readers will be given examples of biological physiological buffers in the form of carbonic acid and gastric fluids. Make sure you have at least read part 12-13 before reading this post to fully understand what is being taught here.
[Tips: In addition to be able to give example of biological buffers, you also need to know how it works to fulfill its function and also what is the consequences if the biological buffer is not present in the system.]
STPM Chemistry Form 6 Notes – Ionic Equilibrium (Part 14 – Final)
Buffer Solution in Biological System
- Physiological pH is to be 7.4
- Venous and arterial pH vary
- Gastric fluids are highly acidic
Case 1: Physiological buffer = carbonic acid (in blood)
Arterial blood (oxygen rich) = slightly higher pH than venous blood (carbon dioxide rich)
When water added to carbon dioxide, it would undergo the following reaction:
CO2(g) + H2O(l) <—-> H2CO3(aq) <—-> HCO3-(aq) + H+(aq)
- Equilibrium regulates blood pH that affect carbon dioxide levels (= affect the pH) and buffering of blood.
- The blood can compensate for the reduced uptake of oxygen by increasing heart rate and producing more red blood cells, but release of carbon dioxide is not easily adjusted.
- This results, blood to be more acidic than normal (respiratory acidosis).
- Vice versa for the respiratory alkalosis results from the excessive loss of carbon dioxide.
Case 2: Physiological buffer = gastric fluids = rich in HCl and highly acidic.
- Loss of gastric fluids results in the loss of acid from the body (metabolic alkalosis).
- This result, vomit or the pumping of the stomach. The acidic solution (in body) must be replenished to reduce the risk of metabolic alkalosis.
- Vice-versa for the food poisoning and drug overdose patients are given a solution of charcoal and water to drink to absorb the organic toxin.
Berry Readers have finally reached the end of this very long series of notes on Ionic Equilibrium for STPM Chemistry Syllabus. Congratulations for lasting this far. Do revise past posts if you have forgotten about any details from the previous 13 posts.