This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Bio-Chemistry), Subject name: Biochemistry
[{'content': 'Best buffer of human blood: \nSelect and explain. \nA. HCO3, B. Chlorides, C. Hb, D. Phosphates', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a (HCO3). (Ref. Guyton physiology 11th ed. 385-387;Ganong, Physiology, 21st/736)# Phosphate buffer system is not important as an extracellular fluid buffer, it plays a major role in buffering renal tubular fluid and intracellular fluids.# The buffer system that is quantitatively the most important in the extracellular fluid--the bicarbonate buffer system.Principal buffers in body fluids1. BloodH2CO3 K H+ +HCO-3 HProt K H+ + Prot- HHb K H+ + Hb-2. Interstitial fluidH2 CO3 KH+ + HCO 33. Intracellular fluidHProt KH + + HCO3, H2PO4 - KH-+ HPO4 2-# For ECF especially blood plasma the predominant buffer is HCO3- (Bicarbonate buffer). Bicarbonate thus acts as major buffers in ICW as well as ECW, but proton s are important buffers only in ICW.', 'role': 'assistant'}]