golgi apparatus1

Golgi ApparatusGroup 1

Content

I. Introduction

II. Location

III. Structure

IV. Functions

V. Synthesis

Images of Golgi Bodies

I. Introduction

The Golgi apparatus is an organelle present in most eukaryotic cells. It is made up of membrane-bound sacs, and is also called a Golgi body, Golgi complex, or dictyosome. Made up of flat membranes called cisternae, the Golgi apparatus also protects against cell destruction known as apoptosis.

Golgi was discovered by an Italian physician and noble laureate Camillo Golgi in 1898 during an investigation of the nervous system.

II. Location

The Golgi apparatus is present in all Eukaryotic cells.It is absent in few cell types, such as mammalian

RBCs, plants sieve tubes.In secretory and absorptive cells, it usually lies

between the nucleus.Plant cells usually have several small Golgi complex,

called Dictyosomes, scattered throughout cytoplasm.

III. Structure

The Golgi apparatus is made up of sacs called cisternae. Usually five to eight cisternae are present in one Golgi apparatus, but as high a number as sixty cisternae have been observed by scientists. These bundles of sacs have five distinct and functional regions, and each region has different enzymes to help it modify the contents, depending on where they are to end up.

Golgi complex varies in size and form in different cell types.Cell may have one large Golgi complex or several very small ones. It occupies different positions in different kind of cells.

IV. Functions

The Golgi apparatus is a major collection and dispatch station of protein products received from the endoplasmic recticulum (ER).

Proteins synthesized in the ER are packaged into vesicles, which then fuse with the Golgi apparatus.

These cargo proteins are modified and destined for secretion via exocytosis or for use in the cell.

Golgi packages and labels protein items which are then send to different parts of the cell.

IV. Functions

Golgi apparatus is responsible for handling macromolecules which are required for proper cell functioning.

The Golgi apparatus works in unison with the endomembrane system.

The Golgi apparatus is sometimes compared to a post office inside the cell since one major function is to modify, sort, and package proteins to be secreted.

Macromolecules – Molecule necessary for life

IV. Functions

Proteins, as well as lipids and polysaccharides, are transported from Golgi apparatus to their final destinations through the secretory pathway.

This involves the sorting of proteins into different kinds of transport vesicles, which bud from the trans Golgi network and deliver their contents to the appropriate cellular locations.

Polysaccharides – Carbohydrate molecules

IV. Functions

Some proteins are carried from the Golgi to plasma membrane by a constitutive secretory pathway, which accounts for the incorporation of new proteins and lipids into the plasma membrane, as well as for the continuous secretion of proteins from the cell.

Other proteins are transported to the cell surface by a distinct pathway of regulated secretion or are specifically targeted to other intracellular destinations, such as lysosomes in animal cells or vacuoles in yeast.

Synthesis in plants

Synthesis in Plants – Cell Wall ComponentsNon cellulose polysaccharides which form part of the cell walls in

plants get synthesized.After they are synthesized, they get sent to the plasma

membrane, they are added to cellulose.When added to cellulose, it is assembled on the exterior part of

the cell wall.

Polysaccharides – Carbohydrate molecules

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