Question

Sodium/Potassium ATPase is the marker enzyme for

• A. Plasma membrane
• B. Mitochondria
• C. Lysosomes
• D. Cytosol

Hint:

The \(\text{Na}^+/\text{K}^+\)-ATPase pump is critical for maintaining resting membrane potentials and osmotic balance across the outer cell wall, which naturally places it exclusively on the plasma membrane.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Certain membrane-bound proteins and active transporters are structurally restricted to specific cellular boundary domains, serving as specific markers.

Step 2: Detailed Explanation:
The Sodium/Potassium pump (\(\text{Na}^+/\text{K}^+\)-ATPase) is an active transport protein that hydrolyzes ATP to export three \(\text{Na}^+\) ions and import two \(\text{K}^+\) ions against their concentration gradients.
This pump is highly abundant and is exclusively embedded within the outer lipid bilayer of eukaryotic cells.
Therefore, \(\text{Na}^+/\text{K}^+\)-ATPase is used biochemically as the definitive marker enzyme for the plasma membrane.

Step 3: Final Answer:
The correct option is 1, which corresponds to Plasma membrane.