Golgi Apparatus

The Golgi apparatus is a organelle in organisms eukaryotes which moves molecules from the endoplasmic reticulum to their destination. The organelle also modifies the products of the endoplasmic reticulum into their final form. The Golgi apparatus is composed of a series of flattened sacs extending from the endoplasmic reticulum.

Overview of the Golgi apparatus

The main function of the Golgi apparatus is the ability to deliver vesicles, or bundles of various cellular products, to different locations in the cell. The Golgi also has important functions by tagging vesicles with proteins and sugar molecules, which serve as identifiers for the vesicles so that they can be delivered to the appropriate target. The organelle is also called the Golgi complex or Golgi body.

Normally, proteins and cellular products are made in the endoplasmic reticulum. The rough endoplasmic reticulum has several ribosomes, which assemble proteins from instructions contained in messenger RNA. Throughout the rest of the endoplasmic reticulum, these protein products are folded and modified. As they reach the Golgi apparatus, further modifications take place. Finally, the products are packaged into vesicles that are ‘tagged’ by other proteins and molecules. The vesicles are released and, according to their tags or labels, the cytoskeleton carries them to the appropriate location within the cell.

Functions of the Golgi apparatus

The Golgi apparatus has many discrete functions. But, all of the functions are associated with moving molecules from the endoplasmic reticulum to their final destination and modifying certain products along the way. The multiple Golgi sacs serve as different chambers for chemical reactions. As the products of the endoplasmic reticulum move through the Golgi apparatus, they are continually transferred to new environments and the reactions that can take place are different.

In this way, one product can receive modifications or multiple products can combine to form large macromolecules. The numerous sacs and folds of the Golgi apparatus allow many reactions to take place at the same time, which increases the rate at which a product can be modified, or multiple products can combine to form large macromolecules. organism can produce products.

Labelling of cellular products

Regardless of the product, the vesicles containing the product move from the endoplasmic reticulum towards the face cis of the Golgi apparatus. In simple terms, this is the side facing the endoplasmic reticulum. The side furthest from the endoplasmic reticulum is known as the trans of the Golgi apparatus, and this is where the products are directed.

After having modifications or additions to their structure, the products are packaged into vesicles and labelled with markers that indicate where the vesicle. These labels can be molecules, such as phosphate groups, or special proteins on the surface of the vesicle. Once tagged, the vesicle is excreted from the Golgi apparatus, on its way to its final destination.

Completion of cellular products

There are many products that are produced by eukaryotes, from proteins that can carry out chemical reactions to lipid molecules that can build new cell membranes. Some products are destined for the endoplasmic reticulum or the Golgi apparatus itself and travel in the opposite direction to most vesicles. While the endoplasmic reticulum produces most of the products and bases used, it is the Golgi apparatus that is responsible for the final presentation and assembly of the products. Often, the environment must be slightly different from that present in the endoplasmic reticulum to obtain certain end products. The many sacs of the Golgi apparatus function to provide many different areas in which reactions can take place under the most favourable conditions.

In secretory cells, or cells that produce large amounts of a substance that your body needs, the Golgi apparatus will be very large. Consider the cells in your stomach which secrete acid. The acid is produced by reactions in the endoplasmic reticulum and is modified as it passes through the Golgi apparatus. Once on the trans of the Golgi apparatus, the acid is packaged into a vesicle and sent to the cell surface. As the vesicle binds to the plasma membraneThe acid is released into the stomach so that it can digest food.

Structure of the Golgi apparatus

The following image shows the structure of the Golgi apparatus. The cis side of the organelle is closer to the endoplasmic reticulum. The trans face is the far side of the corewhich secretes vesicles to various parts of the cell. In addition, there are several lumens and cisternae a through which the products flow. These appear as a series of flattened sacs that are stacked together, just like the endoplasmic reticulum.

Structure of the Golgi apparatus
Structure of the Golgi apparatus

Location of the Golgi apparatus

The Golgi apparatus is located between the endoplasmic reticulum and the cell membrane. Most often, the Golgi appears to be an extension of the endoplasmic reticulum which is slightly smaller and smoother in appearance. However, the Golgi apparatus can easily be confused with a smooth endoplasmic reticulum. Although they look similar, the Golgi is a separate organelle that has different functions.

Theory of Golgi apparatus function.

The most prevalent theory of how the Golgi apparatus is formed is the cisternal maturation model. This model suggests that the sacs themselves tend to move from the face cis to the face trans of the Golgi apparatus over time. New sacs form closer to the endoplasmic reticulum. These sacs “age” as they move towards the face of the endoplasmic reticulum. trans of the Golgi apparatus and its product is fully matured.

Specific products

It may seem that there could never be enough lipids to produce the continuous flow of cell membrane necessary to continuously produce transport vesicles between the endoplasmic reticulum and the Golgi apparatus. However, the endoplasmic reticulum, Golgi apparatus, lysosomes and other organelles of the cell constantly produce and recycle segments of the cell membrane, as well as the outer cell membrane itself. The Golgi apparatus and endoplasmic reticulum work together to produce a new cell membrane, as well as recycle cell membranes from vesicles by fusing two membranes together when vesicles are engulfed.

The Golgi also creates lysosomes. These sacs contain digestive materials. The sacs are separated from the Golgi apparatus and are used to process materials that have been phagocytosed or to digest organelles that no longer function. The lysosome delivers the raw ingredients to the endoplasmic reticulum.

Golgi apparatus in plant cells

While this article mainly discusses the functioning of the Golgi apparatus within animal cells, plant cells also have a Golgi apparatus. In fact, plant cells can contain hundreds of these organelles.

Within plant cells, the Golgi apparatus performs the additional function of synthesising the major molecules of polysaccharide which help to form the cell wall. To do this, plants usually have many more Golgi bodies than an animal cell. In addition, plant cells do not contain lysosomes. These digestive organelles are replaced in the plant with a central lavacuole, which serves as a large lysosome and also as an organelle for storing water. Therefore, many vesicles from plant Golgi bodies move into the lavacuole and fuse their contents with this large organelle.