At about pH 7 in most cells, what happens to the carboxyl R-group on an amino acid?
A) It acts as a base and gains a proton, giving it a positive charge.
B) It acts as an acid and loses a proton, giving it a negative charge.
C) It is oxidized and tends to act as an electron acceptor in redox reactions.
D) It remains neutral, like water, and does not have a charge.

Question

Quizplus · Accepted Answer

At approximately pH 7, the carboxyl R-group on an amino acid acts as an acid and loses a proton (H+), giving it a negative charge. This is because at this pH, there is an equal concentration of H+ and OH- ions in the solution, so the carboxyl group can donate a proton (H+) to the solution, making it negatively charged.

At About PH 7 in Most Cells, What Happens to the Carboxyl