Golgi apparatus is an organelle found in most of the eukaryotes. It consists of a series of flattened membrane sacs called cisternae. These cisternae are present one over the other to form the Golgi complex. It is responsible for packaging proteins into vesicles before secretion and therefore plays a key role in the secretory pathway.
The various functions performed by the Golgi apparatus are: it modifies and processes lipids for cellular use, contributes to the formation of lysosomes for cellular waste management and modifies protein by adding carbohydrates and phosphate groups to proteins. In this article, we will study the Golgi apparatus and diagram its structure, and functions in detail.
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What is Golgi Apparatus?
The Golgi apparatus is a central organelle found in eukaryotic cells. It was first discovered by Camillo Golgi in 1898. It is characterized by stacked membrane sacs known as cisternae. These cisternae are stacked on top of each other to form the Golgi complex. The Golgi complex is mostly found near the nucleus. The Golgi apparatus is made up of approximately four to eight cisternae, although in some single-celled organisms, it may consist of as many as 60 cisternae. Golgi consists of cis and trans faces.
The cis face receives material from the endoplasmic reticulum, and the trans face releases vesicles carrying processed substances to various cellular organs. Animal cells generally contain around 10 to 20 Golgi stacks per cell, which are connected by tubular connections. The plant cells contain many freely distributed subunits of the Golgi Apparatus, called dictyosomes. The Golgi body is not present in bacteria, blue-green algae, mature sperms, and red blood cells of mammals and other animals.
Golgi Apparatus Structure
The shape and size of the Golgi complex depend upon the physiological state of the cells. Mainly it is composed of four parts – cisternae, tubules, vesicles, and vacuoles. The structure of the Golgi apparatus is as follows:
- Golgi Apparatus consists of flat, disc-shaped sacs or cisternae of 0.5µm to 1.0µm diameter. These are stacked parallel to each other.
- The Golgi cisternae are concentrically arranged near the nucleus.
- They have distinct convex cis or the forming face and concave trans or the maturing face. These faces are completely different from each other but are interconnected.
- The organelle has a cis face for receiving materials from the endoplasmic reticulum and a trans face for shipping vesicles to various cellular organs.
- Vesicles move from the cis to the trans face during processing.
- This distinctive structure of the Golgi apparatus allows to efficiently process, modify, and package macromolecules within the cell.
Diagram of Gogli Apparatus
The diagram of golgi apparatus showing its different parts is as follows:
Functions of Gogli Apparatus
The functions of golgi appartus are as follows:
- Golgi apparatus is the important site of formation of glycoproteins and glycolipids.
- Golgi complex help in membrane transformation and membrane recycling.
- Proteins synthesized by the rough endoplasmic reticulum reach the cisternae of the Golgi apparatus where they combine with carbohydrates to form glycoproteins.
- It is essential for proper protein structure and function.
- Golgi apparatus mediates the production of hormones by endocrine glands.
- It modifies and processes lipids for cellular use.
- It forms the matrix of connective tissue.
- Contributes to the formation of lysosomes for cellular waste management.
- It helps in the formation of root hair from their mother cells.
- It packages macromolecules into vesicles for transport.
- In chick embryos, the retinal pigment is synthesized by the Golgi complex.
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FAQs on Golgi Apparatus
1. What is Golgi Apparatus and its Functions?
Golgi appartus, golgi complex are cellular organelles that processes and packages proteins and lipids. It also help in lysosome formation and intracellular transport.
2. Who Discovered the Golgi Apparatus?
Camillo Golgi discovered the Golgi apparatus. He observed densely stained reticular structures near the nucleus. These were later named Golgi bodies after him.
3. What are the functions of Golgi apparatus in storage?
Golgi apparatus help in storage, modification and packaging of products within the cell. It arisis from the endoplasmic reticulum.
4. Where are Golgi Apparatus found in a Cell?
Gogli apparatus is a cellular organelle consisting of stacked membrane sacs called cisternae. The Golgi cisternae are concentrically arranged near the nucleus within the cytoplasm in all eukaryotic cells.
5. What is the Body Structure of the Golgi body?
The Golgi apparatus consists of flattened membrane sacs called cisternae. These are arranged in stacks forming golgi complex. These cisternae, tubules, vesicles and vacuoles make up the structural organization of the Golgi body in eukaryotic cells.