Exocytosis vs. Endocytosis

Main Difference

The main difference between Exocytosis and Endocytosis is that in Exocytosis content release outside the membrane, whereas in Endocytosis content engulfs inside the membrane.

Difference Between Exocytosis and Endocytosis

Comparison Chart

Exocytosis vs. Endocytosis

Word exocytosis is a combination of two words; one is “Exo” means “external” and “cytosis” means “transport mechanism.” Word endocytosis is also a combination of two words; one is “endo” means “internal,” and the other is “cytosis” means “transport mechanism.” Term exocytosis means that “excreting the waste to outside the cell.” Term endocytosis is defined as “the trapping of food particles by engulfing from outside the cell environment. “

In exocytosis, vesicle gets fused with the plasma membrane to excrete out the material. In endocytosis, a vesicle is formed around the food particle to engulf it easily. The process of exocytosis is used for different purposes like neurotransmitters, expel cellular or chemical waste, release hormones, glucose, and proteins at the time of need in other parts of the body. However, the process of endocytosis is used for the purpose of receive nutrients, signal receptors, cell migration, cell adhesion, and at the time of the entry of pathogens.

The secretion of proteins outside the cell is an example of exocytosis. Engulfing of bacteria by neutrophils is an example of endocytosis. In Exocytosis, mainly vesicles built from the Golgi apparatus which contain proteins to dispose of outside the cell and some vesicles contain other waste material. In the endocytosis, the cell wall invaginated itself and created a pocket around the particle, which further pinches off with special proteins and leaves the particle with vesicle inside the cell. The main function of exocytosis is the removal of waste. The important function of endocytosis is taking in the nutrients.

What is Exocytosis?

Exocytosis is the process of expelling too large particles by the cell membrane. To excrete out the waste and other chemicals, a vesicle is formed that surrounds them. However, at some times, the vesicle is formed by the membrane of the molecule. This vesicle swallowed the molecule and pushed it to the edge of the cell membrane from where it goes out of the cell membrane. The vesicle gets fused with the membrane to release the waste contents outside the cell. When a cell is ready to get rid of the toxin substance and to export, the excess protein exocytosis occurs. New protein and lipid molecules that made are move at the top of the plasma membrane.

Waste material of the Golgi apparatus is export outside the cell by the help of secretory vesicles is an example of exocytosis. These secretory vesicles move towards the plasma membrane to release out the external environment. Hormones of our digestive enzymes have also followed the process of exocytosis. As the vesicle contains the dense amount of waste, so they are also known as “dense-core vesicles.” The process of exocytosis is carried out separately by different molecular components such as exosomes, lysosomes, endosomes, etc.

Exocytosis Secretory Pathways

• Constitutive Secretory Pathway: This pathway is used to secrete peptides. Some molecules, like histamine and other enzymes, also followed this pathway. Some secretory proteins are also destined for this type of pathway.
• Regulated Secretory Pathway: This type of pathway is regulated by the soluble stimulant. Ligands are needed to bound with the receptors on the cell membrane is necessary for this pathway.

What is Endocytosis?

Endocytosis is the process for those molecules that are too much large and are unable to pass simply through the plasma membrane. So, in this situation, the membrane engulfs the molecule of protein form the nearer point of the plasma membrane by the process of endocytosis. After engulfing the molecule or protein, there are some receptors at the plasma membrane to which these molecules are get attached for easy transport. When the molecule is getting closer to the plasma membrane, membrane pinched off and makes a sac or vesicle surrounds the molecule and directly moves it to the cytosol.

By endocytosis, a substance is captured from the outside by folds the membrane around the substance to make membrane-bounded sac and eventually push it inside the cell. Vacuole that is formed to taking the matter in the living cell is also known as “endocytic vacuole.” The endocytic vacuole surrounded the content. The process of endocytosis is mainly followed by eukaryotic cells.

Types

• Phagocytosis: Term phagocytosis is also known as “cellular eating.” It involves the engulfing of solid material by making phagocytic vesicles. Phagocytic activity is mostly shown by the unicellular eukaryotes e.g., Amoeba. Amoeba follows the process of phagocytosis to engulf food material. This process is also followed to engulf bacteria, debris and viruses, and other cells. Macrophages and some neutrophils are the best examples of phagocytes.
• Pinocytosis: Term pinocytosis is also known as “cellular drinking.” It involves the engulfing of dissolved substance or liquid material by encircling a pinocytic vesicle.

Conclusion

It is concluded that exocytosis is the outward movement of material, and endocytosis is the inward movement of material.