Consider a protein with the acidic side chains, Amino Acid side-chain Arginine pKa = 12.48
Aspartic Acid PKa = 3.90
Cysteine pKa = 8.33

Glutamic acid pKa = 4.07
Histidine pKa = 6.04
Lysine pKa =10.79
Tyrosine pKa =10.13
Given that the pH of blood is about 7.3, how many of the above side chains would be mostly in their ionic form (A-) in blood?
1. 2
2. 3
3. 4
4. 5

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.

the awnser is group 12