Final answer:
The net charge on glycine at pH 7 is zero, making it neutral. At pH 12, glycine has a net charge of -1.
Step-by-step explanation:
The net charge on the amino acid glycine depends on the pH of the solution. At pH 7, glycine is an zwitterion, meaning that it has both positive and negative charges present. The amino group (NH2) is basic and is protonated (NH3+) at pH 7, while the carboxylic acid group (COOH) is acidic and is deprotonated (COO-) at pH 7. The overall net charge of glycine at pH 7 is zero, making it electrically neutral.
At pH 12, the solution is highly basic. The amino group (NH2) of glycine will be fully deprotonated (NH-) at pH 12, while the carboxylic acid group (COOH) will be deprotonated (COO-). This means that at pH 12, the net charge of glycine will be -1, as it will have one negative charge.