Final answer:
The pKa values of carboxylic acids range from 4 to 5, and at pH 7, they will primarily have a negative charge because they will be in their deprotonated carboxylate ion form.
Step-by-step explanation:
The pKa values of most carboxylic acid groups is about 4 to 5. At pH 7, which is above their pKa range, the majority of these groups will have a negative charge. Carboxylic acids tend to lose their acidic proton (H+) in environments with a pH that's higher than their pKa, resulting in the negatively charged carboxylate ion (-COO-).
In the cellular context, where the pH generally ranges between 7 and 8.5, the carboxyl group of carboxylic acids will exist predominantly in its deprotonated form, that is, as the carboxylate ion. This is due to the acidic nature of the carboxylic acids, which allows them to ionize and release H+ ions into the solution, becoming negatively charged.