At about pH 7 in most cells, what happens to the carboxyl 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 an electron acceptor in redox reactions.
D. It remains neutral, like water, and does not have a charge.
E. None of the above choices occurs