clarifications

Question 1

removal of CO2 from lungs !!

Answer 1

• tissue cells produce a large amount of CO2 as a result of aerobic respiration
• as blood passes through these tissues via blood capillaries, CO2 diffuses into the blood and enters the RBC
• the CO2 reacts with water in RBC to form carbonic acid, catalysed by carbonic anhydrase in RBC, which is a reversible reaction
• the carboic acid is then converted into hydrogen and hydrogencarbonate ions in the blood plasma. A small amount of CO2 is also carried and dissolved in RBC
• in lungs, hydrogencarbonate ions diffuse back into the RBC where they are converted into carbonic acid, then to water and carbon dioxide
• CO2 diffuses out of blood capillaries into the alveoli, where it is expelled during exhalation

Question 2

what is the equation for removal of carbon dioxide in lungs for respiring tissues?

Answer 2

CO2 + H2O (in lungs) –> (carbnic anhydrase) –> H2CO3 (carbonic acid) –> hydrogen + hydrogencarbonate ions

Question 3

take note for removal of CO2 from lungs:

Answer 3

• CO2 tranposrted as ions because it is soluble in water, thus easer and more effective transport. As a gas, carbon dioxide is insoluble in water (being a covalent compound) thus not effective
• only hydrogencarbonate ions diffuse out of RBC