I do not see extra cell death SoI also know that there are t

I do not see extra cell death. So...I also know that there are two types of lysosomes. One type of lysosome recycles materials from within the cell, materials brought in from outside the cells, and phagocytosed invaders. The second class are loaded with enzymes that are inactive in the lysosome, but active at the pH of blood. These lysosomes are targeted to invaders on the outside of cells that either cannot/are not/ or have not been phagocytosed. The fusion of these lysosomes with the cell membrane acts as a warhead releasing proteins that attack the adjacent invader.I think my protease is a part of this \"warhead\" lysosome. In a buffer made from which acid should my protease work?

   A.  
HPO42-

   B.  
CH3COOH

   C.  
H2PO4-

   D.  
NH4+

   E.  
H3PO4

   F.  
HCl

Solution

Answer: C

pH of blood is 7.35. Since th lysosome is active at the pH of blood, H₂PO₄^- has pH close to 7 hence this can be used as buffer.

H3PO4, HCl, CH3COOH have pH below 5.0. The pH of NH4+ is 5.5.

The pKa of dihydrogen phosphate ion is H₂PO₄^- is 7.21 and that of hydrogen phosphate ion HPO₄^-2 is 12.66