Golgi Body or Golgi Complex

Camillo Golgi (1898) first observed densely stained reticular structure near the nucleus. These were later named Gogi bodies after him.

Golgi body also named as :

Lipochondria ( rich in lipids)

Dictyosome (plant golgi body)

 The cytoplasm surrounding Golgi body have fewer or no other organelles. It is called Golgi ground substance or zone of exclusion.

STRUCTURE :

• Golgi complex is made up of three parts - 
• (1) Cisternae :- These are flat disc shaped, sacs like structure many cisternae are arranged in a stack (parallel to each other). Diameter 0.5 um to 1.0 um. Dense opaque material inside cisternae is called Nodes.
• Varied number of cisternae are present in Golgi complex.
• The Golgi cisternae are concentrically arranged near the nucleus.
• Convex surface of cisternae which is towards the nucleus is called cis- face or forming face.
• Concave surface of cisternae which is towards the membrane is called Transface or maturing face
• The cis and trans faces of the organelle are entirely different but inner connected.
• (2) Tubules :- These are branched and irregular tube like structures associated with cisternae.
• (3) Vesicles :- Transition vesicle and Mature vesicle.

fig : Golgi Complex

FUNCTIONS OF GOLGI COMPLEX

Chief function of golgi body is secretion (export) of macromolecules

(1) Cell Secretion :- Chief function of golgi body is secretion (export) of macro molecules.

Secretion involve three steps:

(a) Golgi body receives the materials from E.R. through it's cis - face.

(b) These materials are chemically modified by golgi body. For e g. glycosylation or glycosidation of proteins and lipids takes place in golgi body and it yields glycoproteins and glycolipids.

(c) After chemical modifications materials are packed in vesicles. These vesicles are pinched off from trans face of golgi body and discharged out side the cell

• All the macromolecules which are to be sent out side the cell, move through the golgi body. So golgi body is termed as "Director of macromolecular traffic in cell or middle men of cell.

  The golgi apparatus principally performs the function of packaging materials, to be delivered either to the intra cellular targets or secreted outside the cell. Materials to be packaged in the form of vesicles from the ER fuse with the cis face of the golgi apparatus and move towards the maturing face. This explains why the golgi apparatus remairis in close association with the endoplasmic reticulum.

A number of proteins synthesised by ribosomes on the endoplasmic reticulum are modified in the cisternae of the golgi apparatus before they are released from its trans face. Golgi apparatus is the important site of formation of glycoproteins and glycolipids.

(2) Formation of Lysosome = It is collective function of golgi body and E.R.

(3) Synthesis of cell wall Material (Polysaccharide synthesis).

(4) Cell plate formation (Phragmoplast) during cell formation.

(5) Formation of acrosome during spermiogenesis. (formation of male gametes).