Ty! I saw that question XD didnt try it yet.
That RBC and CO2 transport.I was talking about M/J 2013 question1 part c.
Youre making me feel guilty.....You didnt type ALL this did you?Carbon dioxide molecules are transported in the blood from body tissues to the lungs by one of three methods: (1) dissolution directly into the blood (5%), (2) binding to hemoglobin (10%), or (3) carried as a bicarbonate ion (85%).
First, carbon dioxide is more soluble in blood than is oxygen. Therefore carbon dioxide can be directly carried by blood.
Second, carbon dioxide can bind to plasma proteins or can enter red blood cells, bind to hemoglobin and form a molecule called carbaminohemoglobin is formed. Binding of carbon dioxide to hemoglobin is reversible. Therefore, when it reaches the lungs, the carbon dioxide can freely dissociate from the hemoglobin and be expelled from the body.
Third, the majority of carbon dioxide molecules are carried as part of the bicarbonate buffer system. In this system, carbon dioxide diffuses into the red blood cells. Carbonic anhydrase (CA) within the red blood cells quickly converts the carbon dioxide into carbonic acid (H2CO3). Carbonic acid is an unstable, intermediate molecule that immediately dissociates into bicarbonate ions (HCO3−) and hydrogen (H+) ions. Since carbon dioxide is quickly converted into bicarbonate ions, this reaction allows for the continued uptake of carbon dioxide into the blood, down its concentration gradient. It also results in the production of H+ ions. If too much H+ is produced, it can alter blood pH. However, hemoglobin binds to the free H+ ions, limiting shifts in pH. The newly-synthesized bicarbonate ion is transported out of the red blood cell into the liquid component of the blood in exchange for a chloride ion (Cl-); this is called the chloride shift. When the blood reaches the lungs, the bicarbonate ion is transported back into the red blood cell in exchange for the chloride ion. The H+ ion dissociates from the hemoglobin and binds to the bicarbonate ion.This produces the carbonic acid intermediate, which is converted back into carbon dioxide through the enzymatic action of CA. The carbon dioxide produced is expelled through lungs.
Now I have given a detail explanation of this.Still if you feel any problem in understanding do lemme know.
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