The sodium–potassium exchange pump
(a) Is an example of facilitated diffusion
(b) Does not require the input of cellular energy in the form of ATP
(c) Moves the sodium and potassium ions along their concentration gradients
(d) Is composed of a carrier protein located in the plasma membrane
(e) Is not necessary for the maintenance of homeostasis

Verified step by step guidance

1. Step 1: Understand the function of the sodium–potassium pump. It is a membrane protein that actively transports sodium (Na\(\textsuperscript{+}\)) and potassium (K\(\textsuperscript{+}\)) ions across the plasma membrane to maintain concentration gradients essential for cell function.
2. Step 2: Recall that facilitated diffusion is a passive process that moves substances down their concentration gradients without energy input, whereas the sodium–potassium pump moves ions against their gradients and requires energy.
3. Step 3: Recognize that the pump uses ATP to actively transport 3 sodium ions out of the cell and 2 potassium ions into the cell, which means it requires cellular energy in the form of ATP.
4. Step 4: Identify that the pump is a carrier protein embedded in the plasma membrane, which changes shape to move ions across the membrane.
5. Step 5: Understand the importance of the pump in maintaining homeostasis by regulating ion concentrations, cell volume, and resting membrane potential, making it essential for normal cell function.

Key Concepts

Sodium–Potassium Pump Function

The sodium–potassium pump is a membrane protein that actively transports sodium ions out of the cell and potassium ions into the cell, maintaining essential concentration gradients. This process is vital for cell function, including nerve impulse transmission and muscle contraction.

Active Transport and ATP Usage

Active transport requires energy to move substances against their concentration gradients. The sodium–potassium pump uses ATP to fuel the movement of ions, distinguishing it from passive processes like facilitated diffusion that do not require energy.

Role in Homeostasis

The sodium–potassium pump helps maintain cellular homeostasis by regulating ion concentrations and cell volume. This balance is crucial for normal cell function and overall physiological stability.