In cell biology, which organelle digests cellular waste?

• A. Lysosome
• B. Mitochondrion
• C. Ribosome
• D. Chloroplast

Answer: (A)

Digestion of cellular waste is carried out by lysosomes. These membrane-bound organelles house a suite of acidic hydrolytic enzymes—proteases, lipases, nucleases, and glycosidases—that break down proteins, fats, nucleic acids, and carbohydrates. The interior is kept acidic to optimize enzyme activity, and the lysosome’s membrane protects the rest of the cell from the potent enzymes. Through autophagy and endocytosis, damaged organelles and external material are delivered to lysosomes for breakdown and recycling, turning waste into reusable building blocks. The other organelles have different roles: mitochondria generate ATP, ribosomes synthesize proteins, and chloroplasts perform photosynthesis.