Figure 23.5: Schematic structure of  (A) Golgi bodies and (B) Lysosome.

Lysosomes-Lysosome are discovered by De Duve. They are membrane bound organelles and an important component of intracellular vesicular system (Figure 23.5). They are popularly known as suicidal bags due to their role in autophagy, a cellular process probably operates in cells during starvation to meet their energy requirements. [for more details of molecular mechanism of autophagy and underlying signaling mechanism could be find here: Annu Rev Genet. 2009;43:67-93. Regulation mechanisms and signaling pathways of autophagy]. Lysosome lumen is extremely acidic and contains protease, cytolytic enzymes to degrade the ingested material.

Functions of lysosomes
1. Degradation of ingested food material for delivery through vesicular system.
2. Degradation of pathogenic bacteria
3. Degradation of old protein.