This document discusses lysosomes, which are spherical organelles found in animal cells that contain digestive enzymes. Lysosomes break down food particles, bacteria, and worn out organelles. They were discovered in 1960 and maintain an acidic pH of 4.5-5.0. Lysosomes contain around 40 types of hydrolytic enzymes and vary in size from 0.2-0.8 nm. Their membrane allows enzymes to be released into vacuoles to digest their contents. Plant and fungal vacuoles are similar to lysosomes. Lysosomes function to digest materials through membrane fusion and release of enzymes, acting as the cell's waste disposal and recycling system.

1. Presented by
Surya Pratap Singh
M.Sc. Life Sciences
Central University of Gujarat

2. INTRODUCTION
• Lysosomes discovered by the cytologist
Christian de Duve in the 1960.
• Lysosomes are spherical organelles that
contain enzymes . They break up food so it is
easier to digest. They are found in animal
cells, while in yeast and plants .
• Lysosomes are common in animal cells but
rare in plant cells contain hydrolytic enzymes
necessary for intracellular digestion.

3. STRUCTURES OF LYSOSOME

4. • Lysosomes are spherical structures bounded by a
single unit membrane.
• The size of lysosomes varies from 0.2 to 0.8 nm.
• lysosomal membranes are sensitive to many
labilizers and stabilizers

6. ENZYMES OF LYSOSOMES
• Lysosomes
are
membrane
enclosed
compartments filled with soluble hydrolytic
enzymes.
•
Lysosomes contain about 40 types of
hydrolytic enzymes, including proteases,
nucleases,
glycosidases,
lipases,
phospolipases, phosphatases, and sulfatases.
• Lysosome provides by maintanining a pH
about 4.5 to 5.0.

8. LYSOSOMES ARE HETROGENEOUS
• The hetrogeneity of lysosomal morphology
contrasts with realatively uniform structures
of most other cell organelles.
• The late endosomes contain material
received from both the plasma membrane by
endocytosis
and
newly
synthesized
lysosomal hydrolases.
• Late endosomes fuse
lysosomes
to
form
endolysosomes.
with preexisting
structures
that

9. • Endolysosomes fuse and form lysosomes.
• This reason lysosomes are sometimes
view as a hetrogeneous.

10. PLANT AND FUNGAL VACUOLES ARE SIMILAR TO
LYSOSOMES
• Plant and fungal cells contain one or several very
large fluid-filled vesicles called vacuoles.
• It is related to animal cell lysosomes and
contain a variety of hydrolytic enzymes.
• The plant vacuole can act as a storage organelle
for both nutrients and waste products.
• The vacuole is important as a homeostatic
device.

11. • All these hydrolytic enzymes are produced
in the endoplasmic reticulum, and to some
extent in cytoplasm are transported and
processed through the Golgi apparatus.
• Lysosomal enzymes are synthesized in the
cytosol and the endoplasmic reticulum,
where they receive a mannose-6-phosphate
tag that targets them for the lysosome.
• If the lysosomal enzymes do not reach the
target it causes inclusion-cell disease,
resulting in accumulation of waste within
these organelles

13. THE FUNCTION OF LYSOSOMES
• A lysosome is a membrane bag containing
digestive enzymes.
• For digest food, the lysosome membrane
fuses with the membrane of a food vacuole
and squirts the enzymes inside.
• The digested food can then diffuse through
the vacuole membrane and enter the cell to
be used for energy or growth.
• Lysosomes are sometimes called "suicide bags’’

15. • Lysosomes are the cells' garbage disposal
system. They are used for the digestion of
macromolecules from phagocytosis.
• Lysosome's pick up foreign invaders such
as bacteria, food and old organelles and
break them into small pieces that can
hopefully be used again.
• Autophagy may also lead to autophagic
cell death, a form of programmed selfdestruction, or autolysis of the cell, which
means that the cell is digesting itself.

17. CONCLUSION
• Lysosmes are specialized for the intracellular
digestion of macromolecules.
• These enzymes work only at low pH (highly
acidic) levels.
• Uncontrolled release of lysosome contents into the
cytoplasm can also cause cell death (necrosis).