Q.69 Which of the following eukaryotic cellular components carries out intracellular degradation
during autophagy?
(A) Nucleus (B) Golgi bodies (C) Ribosomes (D) Lysosomes

Lysosomes carry out intracellular degradation during autophagy in eukaryotic cells. This process involves autophagosomes fusing with lysosomes, where hydrolases break down captured cytoplasmic materials. The correct answer is (D) Lysosomes.

Option Analysis

Autophagy recycles damaged organelles and proteins by delivering them to a degradative compartment.

• (A) Nucleus: Houses genetic material and regulates gene expression but does not perform degradation; rare nucleophagy targets nuclear components selectively.

• (B) Golgi bodies: Process and sort proteins/lipids, contributing membranes to autophagosomes but not executing degradation.

• (C) Ribosomes: Synthesize proteins; can be degraded via ribophagy under stress, not the site of degradation.

• (D) Lysosomes: Contain acid hydrolases that degrade autophagosome contents after fusion, central to macroautophagy, microautophagy, and chaperone-mediated autophagy.

Autophagy Overview

Autophagy forms double-membrane autophagosomes engulfing cytoplasm, which fuse with lysosomes for hydrolysis. This maintains homeostasis, especially under starvation.

Lysosomes serve as the primary eukaryotic cellular component for intracellular degradation during autophagy, fusing with autophagosomes to break down cytoplasmic cargo using hydrolases. This mechanism recycles nutrients and clears damaged parts, vital for cell survival.

Autophagy Mechanism

Autophagy sequesters materials in autophagosomes, which mature and merge with lysosomes for enzymatic digestion in the autolysosome. Plants use vacuoles analogously.

Why Not Other Components?

Nucleus, Golgi, and ribosomes play supportive roles but lack degradative enzymes.

Exam Relevance

For CSIR NET, recall lysosomes as the degradative hub in eukaryotic autophagy.