Golgi compex is a complex cytoplasmic structure made up of smooth membrane cisternae, a network of tubules with vesicles or vacuoles, which take part in transformation, secretion and production of complex biomolecules. The Golgi complex was discovered by an Italian scientist Camillo Golgi in 1898. The Golgi complex is found in all eukaryotic cells of plants and animals. However, it is absent in prokaryotic cells. In plant cells the Golgi complex consists of number of unconnected structures known as dictyosomes. The shape and size is not always fixed but usually observed that size of Golgi complex is larger in cells which are young and active. The size is small in inactive and old cells.
Structure:- If observed under electron microscope the Golgi complex consists of the following components - i) Cisternae ii) Vesicles iii) Tubules iv) Vacuoles
i) Cisternae:- These are the tubular or flattened fluid filled sacs, separated by intercisternal spaces 200-300 angstom. Each cisterna is a unit membrane structure. Each cisternae consists of two faces. The convex face which is directed towards the plasmalemma is called forming face while the concave face which is directed towards the nucleus is called maturing face. The maturing face is characterised by the presence of large nucleus.
ii) Vesicles:- These are the small drop like structures measuring about 400-800 angstrom in diameter.
These are associated with convex surface of the Golgi complex. Two types of vesicles smooth and coated vesicles are present.
iii) Tubules:- Theses are structures forming complicated network towards the periphery and maturing face of the cisternae. Tubules have a diameter of 30-50 nm.
iv) Vacuoles:- These are the structures which are present on the maturing surface of the Golgi apparatus. Vacuoles contains an amorphous or granular substances.
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Function:- i) The Golgi apparatus is involved in the synthesis of various enzymes which are essential for transformation of membranes.
ii) Golgi apparatus is actively involved in the secretion through exocytosis or reverse pinocytosis from the cells. It also helps in concentrating and packaging of products of glandular cells.
iii) Proteins released by Rough Endoplasmic Reticulum and lipids from Smooth Endoplasmis Reticulum reach the cisternae of the Golgi appartus.
iv) They are also involved in the formation of mucopolysaccarides, pectin, hemicellulose and microfibrills of a cellulose and therfore helps in the synthesis of plant cell wall.
Structure:- If observed under electron microscope the Golgi complex consists of the following components - i) Cisternae ii) Vesicles iii) Tubules iv) Vacuoles
i) Cisternae:- These are the tubular or flattened fluid filled sacs, separated by intercisternal spaces 200-300 angstom. Each cisterna is a unit membrane structure. Each cisternae consists of two faces. The convex face which is directed towards the plasmalemma is called forming face while the concave face which is directed towards the nucleus is called maturing face. The maturing face is characterised by the presence of large nucleus.
ii) Vesicles:- These are the small drop like structures measuring about 400-800 angstrom in diameter.
These are associated with convex surface of the Golgi complex. Two types of vesicles smooth and coated vesicles are present.
iii) Tubules:- Theses are structures forming complicated network towards the periphery and maturing face of the cisternae. Tubules have a diameter of 30-50 nm.
iv) Vacuoles:- These are the structures which are present on the maturing surface of the Golgi apparatus. Vacuoles contains an amorphous or granular substances.
Function:- i) The Golgi apparatus is involved in the synthesis of various enzymes which are essential for transformation of membranes.
ii) Golgi apparatus is actively involved in the secretion through exocytosis or reverse pinocytosis from the cells. It also helps in concentrating and packaging of products of glandular cells.
iii) Proteins released by Rough Endoplasmic Reticulum and lipids from Smooth Endoplasmis Reticulum reach the cisternae of the Golgi appartus.
iv) They are also involved in the formation of mucopolysaccarides, pectin, hemicellulose and microfibrills of a cellulose and therfore helps in the synthesis of plant cell wall.
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