Golgi Complex, Lysosomes - Position, Structure and  Functions

1.0Golgi Complex (Traffic Police of Cell)

Discovered by Camillo Golgi (1898) in nerve cells of owls.

Golgi apparatus is a cell organelle with single membrane covering. In plants, Golgi bodies are  known as Dictyosomes, as they are found scattered in the plant cell.

Golgi carried out a revolutionary method of staining individual nerve cell structures. This method is referred to as "The black reaction". This method uses a weak solution of silver nitrate and is particularly valuable in tracing the processes and most delicate ramifications of cells. Golgi shared the Nobel prize in 1906 with Santiago Ramony Cajal for their work on structure of the nervous system.

Position

It is located near the nucleus.

Golgi bodies are pleomorphic structures, because components of Golgi body are different in structure and shape in different cells.

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

The Golgi body has a definite polarity. The concave side of Golgi body is always directed towards the cell membrane and is called maturation face or trans face while its convex surface is directed towards the nucleus and is called formative face or cis face. It appears that materials are transported from cis to trans face by vesicles.

Structure

It is formed of four types of structural components. 

Cisternae: These are long flattened and unbranched saccules. 4 to 8 saccules are arranged in a stack. These are concentrically arranged near the nucleus.

Tubules: These are branched and irregular tube like structures associated with cisternae.

Vacuoles: Large spherical structures associated with tubules.

Vesicles: Spherical structures arise by budding from tubules. Vesicles are filled with secretory materials.

Function

(i) Its function includes secretion and acts as storage, modification and condensation or packaging of product within vesicles.

(ii) It forms the acrosome of sperm. (Acrosome is a specialized vesicle present in the head of sperm filled with lytic enzymes which dissolve egg membrane at the time of fertilization.)

(iii) It forms the lysosomes and secretory vesicles.

(iv) It is the site of formation of glycolipids and glycoproteins.

(v) Synthesis of cell wall material (polysaccharide synthesis).

(vi) Cell plate formation during plant cell division.

2.0Lysosomes (Little Enzyme Packages/Waste Disposal System of The Cell) 

Lysosomes are spherical bag like structures covered by single membrane. Lysosomes hold enzymes that were created by the cell. The purpose of the lysosome is to keep the cell clean by digesting any foreign materials as well as worn-out cell organelles. They might be used to digest food or break down the cell when it dies. They are garbage disposer of the cell.

A lysosome is basically a specialized vesicle that holds a variety of hydrolytic enzymes which functions at acidic pH. The enzyme proteins are first created in the rough endoplasmic reticulum. Those proteins are packaged in a vesicle and sent to the Golgi apparatus. The Golgi then does its final work to create the digestive enzymes and pinches it off in the form of a small specific vesicle. That vesicle is a lysosome. From there, the lysosomes float in the cytoplasm until they are needed.

Lysosomes are called digestive bags because they contain lots of digestive enzymes.

3.0Also Read