Question

Acid phosphatase is the marker enzyme for

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

Hint:

Associate hydrolytic enzymes requiring highly acidic environments (like acid phosphatase) directly with lysosomes, as the lysosomal lumen maintains an acidic pH (\(\approx 4.5\text{--}5.0\)) optimized for these hydrolases.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Organelle marker enzymes are specific enzymes uniquely localized or highly concentrated within a particular cellular organelle.
Measuring the activity of these markers is a standard biochemical method used to assess the purity of isolated cellular fractions.

Step 2: Detailed Explanation:
Let us identify the target organelles for each option:
1. Plasma membrane: Standard marker enzymes include \(\text{Na}^+/\text{K}^+\)-ATPase and 5'-nucleotidase.
2. Mitochondria: Standard marker enzymes include succinate dehydrogenase and cytochrome c oxidase.
3. Lysosomes: Acid phosphatase is a classic hydrolytic enzyme functioning under acidic pH, making it the definitive marker enzyme for lysosomes.
4. Cytosol: Lactate dehydrogenase (LDH) is commonly used as a marker enzyme.
Thus, acid phosphatase is the marker enzyme for lysosomes.

Step 3: Final Answer:
The correct option is 3, which corresponds to Lysosomes.