LYSOSOME
The lysosome
is a simple but essential organelle found in the vast and highly organized
field of cell biology. Sometimes referred to as the "Suicidal Bag". As it contains various hydrolytic enzymes
which can digest the waste and unnecessary components and molecules of the
cell. Therefore it plays crucial role to maintain health and function of cells.
Structure of the Lysosome
Lysosomes
are membrane-bound organelles that can vary in size from 0.2 to 0.3 micrometers
in diameter. The interior of the lysosome is acidic with a pH between 4.5 and
5.0 which is necessary for the enzymes present in it to function. High Hydrogen
ion concentration inside the lysosome is maintained by proton pumps that actively
transport hydrogen ions into the lysosome by consuming ATP.
Enzyme Arsenal
What really
sets lysosomes apart is their vast array of digestive enzymes. These hydrolytic
enzymes function in acidic PH (4.5-5) and play a significant role in the
breakdown of a wide range of biological substances, including proteins, nucleic
acids, lipids and carbohydrates. Proteases (for protein digestion), nucleases
(for nucleic acid digestion), lipases (for lipid digestion) and glycosidases
(for carbohydrate digestion) are some of the most important enzymes found in
lysosomes. It is also used to digest the old and damaged cells that no longer
perform their tasks.
The
biological substances digested are further recycled and used up other cells in
their basic cellular functioning. This recycling process is important to
maintain the cell's energy balance and to limit the accumulation of damaged or
non-functioning biomolecules.
Functions of Lysosomes
1) Waste disposal: Lysosomes serve as the cell's waste disposal system, breaking down and recycling cellular debris, aging organelles, and infections such as bacteria and viruses. This process is called autophagy, which helps in cleaning the waste of the cell and functioning.
2) Release of nutrients: Lysosomes can break down stored resources such as glycogen and release the resulting molecules such as glucose into the cytoplasm for energy production when the cell needs nutrients.
3) Programmed Cell Death: Lysosomes play a role in programmed cell death, often referred to as apoptosis. They release hydrolytic enzymes that break down the components of the cell, leading to controlled breakdown of cell.
4) Defense Mechanism: Lysosomes are involved in the immune response by fusing with phagosomes, which are enveloped vesicles that contain dangerous invaders such as bacteria. These invaders are then digested by lysosomal enzymes.
Disease and dysfunction
Lysosomal storage diseases are a group of diseases that occur when the lysosomes malfunction. These are mainly rare inherited diseases characterized by the accumulation of undigested chemicals in the lysosomes. Tay-Sachs disease in which enzymes necessary for the digestion of few fatty acids are absent leading to the formation of toxic substances that ultimately accumulate in the brain and spinal cord affecting its functioning and Gaucher
disease are two examples of diseases that can have serious or even fatal consequences.
Conclusion
In
conclusion, we can say that the lysosome, though being a small cellular
organelle is very crucial for the cell cleanup mechanism. It is present in
eukaryotic cells and is a single membrane-bound structures containing
hydrolytic enzymes that are active in acidic pH.
Its ability
to degrade cellular components and even the whole cell which has become aged or
not functioning properly is very crucial for maintaining cellular homeostasis
and overall health of the cell.
