What is Difference Between Endocytosis and exocytosis?
Difference Between Endocytosis and exocytosis is that The endocytosis is the transport of particles and substances into the cell, while the exocytosis is the transport of intracellular material outward. Both processes are due to the need of the cell to maintain with its surroundings an exchange of materials for its survival.
Both endocytosis and exocytosis are mechanisms involved in the transport of materials through the plasma membrane. This is a type of active mass transport that requires energy in the form of ATP.
| Endocytosis | Exocytosis | |
|---|---|---|
| Definition | The cellular mechanism to trap substances from the extracellular environment. | The cellular mechanism to release or export content to the extracellular medium. |
| Process | The plasma membrane envelops and surrounds the substance. | Intracellular vesicles fuse with the plasma membrane. |
| Types | Phagocytosis (solid material) and pinocytosis (liquid material). | Constitutive secretory pathway and regulated secretory pathway. |
| Vesicle formation | Internal endocytic vesicles, called phagosomes, form | The secretory vesicles form in the Golgi apparatus. |
| Example | A white blood cell ingesting a bacterium. | Endocrine cells release hormones by exocytosis. |
What is endocytosis?
Endocytosis is the process by which cells capture material from the extracellular environment. In this process, the material to be ingested gradually closes in a small portion of the plasma membrane, which is introduced or invaded into the cell, to finally separate from the membrane and form an endocytic vesicle.
Cells use endocytosis to trap nutrients, such as vitamins, cholesterol, and iron. Depending on the size and consistency of the material to be ingested, there are two types of endocytosis: phagocytosis and pinocytosis.
Phagocytosis
Phagocytosis is the endocytosis of solid and large particles. Another way of looking at the phagocytosis process is like “the cell eating.” An example is unicellular organisms, such as amoebas, that use phagocytosis to feed.
In multicellular higher organisms, there are cells known as “professional phagocytes,” such as white blood cells or leukocytes and macrophages. These cells are responsible for defending the body against invading agents, such as bacteria, viruses, and parasites.
The vesicle resulting from phagocytosis is called phagosome. These phagosomes fuse with lysosomes, which are the intracellular organelles responsible for the digestion of the material.
Pinocytosis
Pinocytosis is the internalization of dissolved molecules in a fluid. Pinocytosis can be translated as “the drinking cell”.
What is exocytosis?
Exocytosis is the cellular process to release material abroad. It is the reverse process of endocytosis. From the Golgi apparatus, vesicles are formed to fuse with the plasma membrane. There are two ways to excite secretion: constitutive and regulated.
Constitutive secretory route
In this way, the vesicles fuse with the plasma membrane continuously. This is the way the cell eliminates waste.
Regulated secretory pathway
To activate this pathway, some special signal is required within the cell that tells you that you must release the products within your secretory vesicles. This pathway is mainly found in cells specialized in secreting products, such as neurons, that release neurotransmitter, or endocrine cells that release hormones.
What is transcytosis?
In some cells, such as endothelial cells, the material is transported from one side of the cell to the other. This process is known as transcytosis.
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