In competitive exams like UPSC, SSC, RRB NTPC, and State PSCs, questions on cell organelles are quite common. One frequently asked topic is:
“Why are lysosomes called the ‘suicidal bag’ of the cell?“
Understanding this not only helps in biology questions but also enhances clarity in related topics like cell structure, metabolism, and human physiology.
Let’s break this concept down in a simple, exam-ready format!
What Are Lysosomes?
✅ Definition
Lysosomes are membrane-bound organelles found in the cytoplasm of animal cells. They contain digestive enzymes that break down waste materials, worn-out cell parts, and foreign invaders.
✅ Discovery
◾ Discovered by: Christian de Duve
◾ Year: 1955
✅ Structure
◾ Single membrane-bound vesicles
◾ Contain hydrolytic enzymes (around 50 types)
◾ Function best at acidic pH (~5)
Why Are They Called “Suicidal Bags”?
✅ Explanation
Lysosomes are called “suicidal bags” because they can digest the cell’s own components in case of cell damage, infection, or aging — leading to cell death.
How It Happens
◾ Under stress or injury, the lysosomal membrane may rupture.
◾ The released enzymes then digest the cell’s cytoplasm and organelles.
◾ This process is known as autolysis (auto = self, lysis = breakdown).
◾ Hence, they “kill” their own cell — thus the term “suicidal bag.”
Functions of Lysosomes
✅ Major Functions
◾ Intracellular digestion of macromolecules
◾ Removal of dead or damaged organelles (Autophagy)
◾ Destruction of pathogens like bacteria (Phagocytosis)
◾ Apoptosis regulation (programmed cell death)
✅ Types of Digestion
| Function | Description | Example |
|---|---|---|
| Heterophagy | Digestion of external materials | Engulfing bacteria |
| Autophagy | Digestion of internal cell parts | Damaged mitochondria removal |
| Autolysis | Self-destruction of the entire cell | In case of severe cell damage |
Mnemonic Trick to Remember
Mnemonic: Lysosome = “Lysis”-some
🔹 “Lysis” means breaking down, and “some” refers to body → So, “breaking body” (even its own)!
Summary Notes (Quick Revision)
| Feature | Key Points |
|---|---|
| Organelle Name | Lysosome |
| Discovered by | Christian de Duve (1955) |
| Found in | Animal cells (rare in plant cells) |
| Structure | Single membrane with digestive enzymes |
| Function | Digestion, waste removal, self-death |
| Nickname | “Suicidal Bag of the Cell” |
| Related Process | Autolysis |
| Important Enzymes | Hydrolases (proteases, nucleases, lipases) |
Practice Questions (MCQs for Exam)
Who discovered lysosomes?
a) Robert Hooke
b) Christian de Duve
c) Anton van Leeuwenhoek
d) Matthias Schleiden
✅ Answer: b) Christian de Duve
Why are lysosomes called the “suicidal bags” of the cell?
a) Because they produce energy
b) Because they digest food
c) Because they destroy harmful bacteria
d) Because they can digest the cell itself
✅ Answer: d) Because they can digest the cell itself
Which enzymes are found in lysosomes?
a) Oxidases
b) Hydrolytic enzymes
c) Polymerases
d) Ligases
✅ Answer: b) Hydrolytic enzymes
What is autolysis?
a) Digestion of external food
b) Breaking down of DNA
c) Self-digestion by lysosomes
d) Removal of waste by vacuoles
✅ Answer: c) Self-digestion by lysosomes
Lysosomes are commonly found in:
a) Plant cells
b) Bacteria
c) Animal cells
d) Fungi only
✅ Answer: c) Animal cells
Conclusion
Lysosomes are vital cellular housekeepers, ensuring the cell stays clean and healthy. However, when the situation demands, they can cause the cell’s death to protect the body. This self-destructive ability makes them rightly known as the “suicidal bags of the cell.”
This concept is essential for school-level science and highly relevant for competitive exams, where understanding such analogies and functions helps in scoring well.
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