Lysosomes are the small vesicles present in a cell. These small vesicles are containing strong hydrolytic enzymes which are helpful in the intracellular digestion ( the digestion which takes place inside the cell). Lysosomes is a single layered organelle involved in various cellular functions.
Lysosomes were first discovered by Belgian scientist, Christian de Duve, in 1955. Lysosomes are present in all animals cells except R.B.C of mammals. In plants and fungi their function is taken over by vacuoles. Enzymes which are present in lysosomes are called acid hydrolases because these enzymes works in the strong acidic medium. The important enzymes are acid phosphatases, sulphatases, proteases, peptidases, nucleases, lipases and carbohydrases.
Lysosomes are mainly originated from plasma membrane by the process of invagination and folding. They are also arise from smooth endoplasmic reticulum or Golgi bodies. The precursors of the enzymes are formed by rough endoplasmic reticulum, then these precursors are transfers to the maturing face of Golgi bodies for maturation. These precursors are then changed into the functional enzymes. These enzymes are then packed in a larger vesicles and these vesicles are when joined with the endosomes are called lysosomes.
For digestion the materials will enter inside the lysosomes where this materials will be acted by the enzymes. Lysomes do not burst in the cytoplasm of the cell to digest any materials.
Polymorphism:- Polymorphism is the term which represents the existence of more than two morphological structures. Depending upon the different structures lysosomes are of four types:-
a) Primary Lysosomes:- These are the newly formed vesicles which are pinched off from Golgi complex. These vesicles when fused with endosomes then will become fully functional. They are small in size.
b) Secondary Lysosomes:- These are also called digestive vacuoles. The food containing phagosomes and lysomes when fuse together will form secondary lysosomes. Digestion occur. The digested food will pass out to the cytoplasm and the lysosomes is left with indigested food.
c) Residual Bodies:- These are the left over or indigested food in the lysosomes. These structures fuse with the plasma membrane to throw out into the external environment called exocytosis or ephagy.
d) Autophagic vacuoles:- These are the fusion of number of primary lysosomes aruond warn out or degenerate intracellular organelles. These organelles are then digested by the strong hydrolytic enzymes of the lysosomes. This is called autophagy or autodigestion.
Functions of Lysosomes
Functions:-
i) Lysomes are mainly involved in the intracellular as wall as extracellular digestion. The extracellular digestion takes place by the secretion of enzymes by lysosomes outside the cell into external environment.
ii) Lysosomes present in leucocytes helps in the digestion of foreign particles, proteins and microorganisms. In this way they are the main part of immune system.
iii) The lysosomal enzymes present in the acrosome of sperm helps in the breaking limiting membrane of the egg.
iv) They are helpful in the dispose off of useless cells ( aging and dead cells in the body).
Lysosomes were first discovered by Belgian scientist, Christian de Duve, in 1955. Lysosomes are present in all animals cells except R.B.C of mammals. In plants and fungi their function is taken over by vacuoles. Enzymes which are present in lysosomes are called acid hydrolases because these enzymes works in the strong acidic medium. The important enzymes are acid phosphatases, sulphatases, proteases, peptidases, nucleases, lipases and carbohydrases.
Lysosomes are mainly originated from plasma membrane by the process of invagination and folding. They are also arise from smooth endoplasmic reticulum or Golgi bodies. The precursors of the enzymes are formed by rough endoplasmic reticulum, then these precursors are transfers to the maturing face of Golgi bodies for maturation. These precursors are then changed into the functional enzymes. These enzymes are then packed in a larger vesicles and these vesicles are when joined with the endosomes are called lysosomes.
For digestion the materials will enter inside the lysosomes where this materials will be acted by the enzymes. Lysomes do not burst in the cytoplasm of the cell to digest any materials.
Polymorphism:- Polymorphism is the term which represents the existence of more than two morphological structures. Depending upon the different structures lysosomes are of four types:-
a) Primary Lysosomes:- These are the newly formed vesicles which are pinched off from Golgi complex. These vesicles when fused with endosomes then will become fully functional. They are small in size.
b) Secondary Lysosomes:- These are also called digestive vacuoles. The food containing phagosomes and lysomes when fuse together will form secondary lysosomes. Digestion occur. The digested food will pass out to the cytoplasm and the lysosomes is left with indigested food.
c) Residual Bodies:- These are the left over or indigested food in the lysosomes. These structures fuse with the plasma membrane to throw out into the external environment called exocytosis or ephagy.
d) Autophagic vacuoles:- These are the fusion of number of primary lysosomes aruond warn out or degenerate intracellular organelles. These organelles are then digested by the strong hydrolytic enzymes of the lysosomes. This is called autophagy or autodigestion.
Functions of Lysosomes
Functions:-
i) Lysomes are mainly involved in the intracellular as wall as extracellular digestion. The extracellular digestion takes place by the secretion of enzymes by lysosomes outside the cell into external environment.
ii) Lysosomes present in leucocytes helps in the digestion of foreign particles, proteins and microorganisms. In this way they are the main part of immune system.
iii) The lysosomal enzymes present in the acrosome of sperm helps in the breaking limiting membrane of the egg.
iv) They are helpful in the dispose off of useless cells ( aging and dead cells in the body).
prof premraj pushpakaran writes -- 2017 marks the 100th birth year of Christian de Duve!!!
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