Hydrogen ions produced in human red blood cells are prevented from significantly lowering pH by combining with

Question

a plasma buffers.

b plasma proteins.

c carbon dioxide.

d carbonic acid.

e hemoglobin.

Answer 1

b

Answer 2

CO2 combines with water (H2O) to form H2CO3 (carbonic acid) which dissciates into H+ and HCO3- ions in presence of enzyme 'carbonic anhydrase'

- HCO3- ions diffuse into plasma to act as buffer (Bicarbonate buffer) by neutralising excess H+ ions in plasma.

- Excess H+ ions in RBCs, however, combine with globin part of Hemoglobin.

so, answer is choice E

(see attached article under heading 'CO2 transport'

http://users.rcn.com/jkimball.ma.ultrane...