Cell organelles — functional role of lysosomes Lysosomes in eukaryotic cells are primarily associated with which cellular process?

Introduction / Context:
Lysosomes are acidic, enzyme-rich organelles found in many eukaryotic cells. They mediate breakdown and recycling of biological macromolecules, enabling turnover of organelles and defense against pathogens. Correctly identifying their core function helps integrate knowledge across cell biology and pathology.

Given Data / Assumptions:

• Lysosomes contain hydrolytic enzymes that work optimally at low pH.
• They fuse with endocytic vesicles and autophagosomes.
• They are not the site of photosynthesis or oxidative phosphorylation.

Concept / Approach:

Lysosomal enzymes degrade proteins, nucleic acids, lipids, and carbohydrates. The products are transported back to the cytosol for reuse. This autophagy and heterophagy function is essential for cellular homeostasis and adaptation to nutrient stress.

Step-by-Step Solution:

Verification / Alternative check:

Microscopy and biochemical assays show colocalization of lysosomal markers with cargo destined for degradation, confirming the digestive function.

Why Other Options Are Wrong:

Photosynthesis occurs in chloroplasts. ATP synthesis by oxidative phosphorylation occurs in mitochondria. Long term nutrient storage is a function of plastids or vacuoles, not lysosomes. Signal transduction is primarily at membranes and cytosol, not within lysosomes, although they can participate indirectly.

Common Pitfalls:

Confusing lysosomes with peroxisomes or assuming all degradation occurs in proteasomes. Lysosomes specialize in bulk and membrane cargo degradation.

Final Answer:

Digestion of macromolecules and cellular recycling