1. LYSOSOMES
Mr. Nirbhay Sudhir Pimple
Asst. Professor
Department of Zoology
Abasaheb Garware College
Karve road, Pune-4.
(nirbhay.pimpale@mesagc.org))
)
3. • What are Lysosomes…?
• Lysosomes are spherical organelle that
contain enzymes acid hydrolyses. They break
up food so it is easier to digest. They are found
in animal cells, while in yeast and plants the
same roles are performed by lytic vacuoles.
• Discovered by De Duve in 1955.
• 1st electron micrograph by Novikoff. In 1974
De Duve got Nobel prize.
Nirbhay S. Pimple/Dept of Zoology/AGC Pune-4.
4. Lysosomes are common in animal cells but rare in
plant cells contain hydrolytic enzymes necessary for
intracellular digestion.
The size of lysosomes varies from 0.1–0.8 μm. They
are larger in phagocytes(WBC) 0.8-2 μm.
Nirbhay S. Pimple/Dept of Zoology/AGC Pune-4.
6. All these hydrolytic enzymes are
produced in the endoplasmic
reticulum, and to some extent in
cytoplasm are transported and
processed through the Golgi
apparatus and through golgi
apparatus they pinch off as single
membrane vesicles.
Nirbhay S. Pimple/Dept of Zoology/AGC
Pune-4.
7. •It is called :
•"The Police Force of the
Cell"
•"suicide bags“
•“Stomach of cell”
Nirbhay S. Pimple/Dept of Zoology/AGC
Pune-4.
8. SITE OF SYNTHESIS
Lysosomes are produced in the Golgi Apparatus
Nirbhay S. Pimple/Dept of Zoology/AGC
Pune-4.
9. • A lysosome is a membrane bag
containing digestive enzymes to 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.
Nirbhay S. Pimple/Dept of Zoology/AGC Pune-4.
11. • Lysosomes are the cell’s garbage disposal system.
• They are used for the digestion of macromolecules from
• 1.Phagocytosis (ingestion of larger extracellular material,
like foreign invading microbes) .
• 2.Endocytosis (ingestion of macromolecules where
receptor proteins are recycled from the cell surface), and
• 3.Autophagy (wherein old or unneeded organelles or
• proteins, or microbes that have invaded the cytoplasm are
delivered to the lysosome).
• Autophagy may also lead to autophagic cell death, a form
of programmed self-destruction, or autolysis, of the cell,
which means that the cell is digesting itself
Nirbhay S. Pimple/Dept of Zoology/AGC Pune-4.
12. • Lysosomes pick up foreign invaders such as bacteria,
food and old organelles and break them into small
pieces that can hopefully be used again.
• (Recycling unit of cell)
• In human liver cells it is calculated that at least one
mitochondria undergoes autophagy every 10 minutes.
• This reflects the highly active nature of the liver as
an organ and it's need for a constant supply of fresh
organelles. The electron micrograph below shows a
lysosome in the process of destroying a membrane
bound mitochondria.
Nirbhay S. Pimple/Dept of Zoology/AGC Pune-4.
13. • Tay Sach’s Disease
• 16 • A lysosomal storage disease(LSD)
• – Due to a mutation in lysosomal enzymes
• B-N-hexosaminidase-A*
• Accumulations of un-degraded glycolipid
(Ganglioside) within lysosomes in brain
NERVE CELL
• Found in neurons of CNS
• Diagnostic feature-Cherry red spot on
Retina(By Tay-name of scientist)
• Autosomal recessive genetic disorder
Nirbhay S. Pimple/Dept of Zoology/AGC Pune-4.
14. • Pompe’s Disease- lysosomes of some people lack
enzymes for digestion of Glycogen. In such persons
excessive storage of glycogen occurs in liver.
• 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.
Nirbhay S. Pimple/Dept of Zoology/AGC
Pune-4.
15. FACTS
• The only thing that keeps the cell itself from
being digested is the membrane surrounding the
lysosomes.
Highly polymorphic cell organelle.
• Lyosomes of Osteoclast cells(bone eating cells)
dissolves
• unwanted part of bones.
• Crinophagy - Excessive secretion of hormone in
endocrine
• gland may be digested by lysosomes.
Nirbhay S. Pimple/Dept of Zoology/AGC
Pune-4.
16. • These enzymes work only at low pH
(highly acidic) levels.
• However because they can only work
at low pH levels and the rest of the
cell has a neutral pH level, they can
be neutralized if they accidentally
escape from the lysosome
Nirbhay S. Pimple/Dept of Zoology/AGC
Pune-4.
17. • In white blood cells that eat
bacteria, lysosome contents are
carefully released into the vacuole
around the bacteria and serve to kill
and digest those bacteria.
Uncontrolled release of lysosome
contents into the cytoplasm can also
cause cell death (necrosis).
Nirbhay S. Pimple/Dept of Zoology/AGC Pune-4.
