What combination of ion movements occurs during ATP hydrolysis in the absence of digoxin?

What combination of ion movements occurs during ATP hydrolysis in the absence of digoxin?

• A. 1 K+ in; 2 Na+ out
• B. 3 Na+ out; 2 K+ in
• C. 2 K+ out; 1 Na+ in
• D. 1 Na+ out; 3 K+ in

Answer: (B)

During the process of ATP hydrolysis, particularly in the context of the sodium-potassium pump (Na+/K+ ATPase), there is a specific pattern of ion movements that occurs to maintain the electrochemical gradients across the cell membrane. The Na+/K+ ATPase actively transports three sodium ions out of the cell and two potassium ions into the cell for each ATP molecule hydrolyzed. This movement creates an essential gradient that is crucial for various cellular functions, including maintaining osmotic balance and generating action potentials in neurons. In the absence of digoxin, which is a cardiac glycoside that inhibits the sodium-potassium pump, the normal function of this pump is preserved. The direct result of this ATP hydrolysis is the outward movement of three sodium ions (Na+) and the inward movement of two potassium ions (K+). This establishes a net positive charge outside the cell and a net negative charge inside the cell, facilitating the resting membrane potential. The correct combination of ion movements correlates directly with this established mechanism of the sodium-potassium pump, highlighting the role of ATP in driving these processes.

During the process of ATP hydrolysis, particularly in the context of the sodium-potassium pump (Na+/K+ ATPase), there is a specific pattern of ion movements that occurs to maintain the electrochemical gradients across the cell membrane. The Na+/K+ ATPase actively transports three sodium ions out of the cell and two potassium ions into the cell for each ATP molecule hydrolyzed. This movement creates an essential gradient that is crucial for various cellular functions, including maintaining osmotic balance and generating action potentials in neurons.

In the absence of digoxin, which is a cardiac glycoside that inhibits the sodium-potassium pump, the normal function of this pump is preserved. The direct result of this ATP hydrolysis is the outward movement of three sodium ions (Na+) and the inward movement of two potassium ions (K+). This establishes a net positive charge outside the cell and a net negative charge inside the cell, facilitating the resting membrane potential.

The correct combination of ion movements correlates directly with this established mechanism of the sodium-potassium pump, highlighting the role of ATP in driving these processes.