Shift of HCO3– out of RBC in exchange for Cl– is known as
**Core Concept:** The question is testing the understanding of the process by which bicarbonate ions (HCO3-) move into or out of red blood cells (RBCs) in exchange for other ions. This process is crucial for maintaining the balance of ions in the body and for cellular functions.
**Why the Correct Answer is Right:** The correct answer, C. Anion exchanger (AE) 1, is responsible for the movement of bicarbonate ions (HCO3-) into RBCs in exchange for chloride ions (Cl-). AE1 is a membrane protein found on the surface of RBCs and plays a vital role in maintaining the pH balance and transporting bicarbonate ions into the RBCs.
**Why Each Wrong Option is Incorrect:**
A. Heme oxygenase: Heme oxygenase is an enzyme involved in the degradation of heme, not related to the movement of ions between RBCs.
B. Band 3: Band 3 is a membrane protein, but it is responsible for anion transport in the basolateral membrane of the red cell, not for moving HCO3- into the RBCs.
D. ClC-1: ClC-1 is a chloride ion channel, not involved in the exchange of HCO3- for Cl-.
**Clinical Pearl / High-Yield Fact:** AE1 is a crucial protein for maintaining acid-base balance and preventing the accumulation of toxic levels of HCO3- in RBCs. This process is essential for the proper functioning of RBCs and overall human health.
**Correct Answer:** C. Anion exchanger (AE) 1