Which of the following best describes the energy requirement and ion transport mechanism of NaK ATPase?

• A. NaK ATPase transports 2 sodium ions into the cell and 3 potassium ions out, using 1 ATP.
• B. NaK ATPase transports 3 sodium ions into the cell and 2 potassium ions out, using 1 ATP.
• C. NaK ATPase transports 3 sodium ions out of the cell and 2 potassium ions in, using 1 ATP.
• D. NaK ATPase transports 2 sodium ions out of the cell and 3 potassium ions in, using 1 ATP.

Answer: (C)