Question

Which of the following enzymes is NOT present in lysosomes?

• A. Phosphatase
• B. Polymerase
• C. Lipase
• D. Protease

Hint:

Lysosomes contain only "hydrolases" (degradative enzymes that break chemical bonds using water). Polymerases are "synthesizing" enzymes involved in replication and transcription, located in the nucleus and organelles, never in lysosomes.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Lysosomes are membrane-bound organelles that function as the cellular "recycling center" or waste disposal system.
They contain a wide variety of acid hydrolases that degrade old organelles, pathogens, and macromolecules.

Step 2: Detailed Explanation:
Let us review the enzymes present in lysosomes:
Lysosomes contain about 50 different hydrolytic enzymes that operate optimally in acidic conditions (pH $\approx 4.5 - 5.0$). These include:
1. Phosphatases (A): Such as acid phosphatase, which removes phosphate groups from organic molecules.
2. Lipases (C): Which break down lipids and fatty acid esters.
3. Proteases (D): Such as cathepsins, which break down proteins into amino acids.
4. Nucleases: Which degrade nucleic acids (DNA and RNA) into nucleotides.
Polymerases (B): These are biosynthetic enzymes (such as DNA polymerase and RNA polymerase) responsible for synthesizing new DNA and RNA strands.
These enzymes require neutral to slightly alkaline conditions and are located in the nucleus, mitochondria, and chloroplasts. They are never found in lysosomes, which are purely degradative organelles.

Step 3: Final Answer:
Polymerase is not present in lysosomes, which corresponds to option (B).