To determine which buffer system is mainly contained in our blood, let's examine each pair given in the options:
A) [tex]\(NH_4^+ / NH_3\)[/tex]
- Ammonium ion [tex]\(NH_4^+\)[/tex] and ammonia [tex]\(NH_3\)[/tex] do form a buffer system, but this system is not prevalent in human blood.
B) [tex]\(HC_2H_3O_2 / C_2H_3O_2^-\)[/tex]
- This is the acetic acid/acetate buffer system, which is more common in biological systems outside human blood, such as in certain laboratory settings.
C) [tex]\(HPO_4^{2-} / PO_4^{3-}\)[/tex]
- The phosphate buffer system [tex]\(HPO_4^{2-} / PO_4^{3-}\)[/tex] does play a role in regulating pH in some body fluids but is not the primary buffer system in blood.
D) [tex]\(H_2CO_3 / HCO_3^-\)[/tex]
- This is the carbonic acid/bicarbonate buffer system. It is the major buffer system in human blood and plays a crucial role in maintaining the pH balance in the bloodstream. Bicarbonate ions [tex]\(HCO_3^-\)[/tex] neutralize excess acids in the blood, while carbonic acid [tex]\(H_2CO_3\)[/tex] balances the bases.
After reviewing all options, the buffer system that is mainly contained in our blood is:
D) [tex]\(H_2CO_3 / HCO_3^-\)[/tex]
