Exocytosis Vs. Endocytosis
Two key functions in which your cells engage are exocytosis and endocytosis. The definitions of exocytosis and endocytosis are as follows. Endocytosis and Exocytosis. Endocytosis is the process of capturing a substance or particle from outside the cell by engulfing it with the cell. They are both types of active transport, requiring the use of energy by the cell, and they are the opposite processes.
Endocytosis and Exocytosis
Endocytosis Exocytosis is the reverse of endocytosis. This article gives you a brief explanation of these processes and also compares the two.
BiologyWise Staff The cells inside an organism's body perform actions like secreting chemicals, releasing energy, expelling wastes, etc. For these functions, body cells carry out the processes of exocytosis and endocytosis.
Let's understand the two in detail and also find the differences between them. Exocytosis In this process, a cell expels molecules and other contents that are too large to pass through the cell membrane structure.
This discharge is accompanied by the fusion of the vesicular membrane and the plasma membrane. This process is carried out in three ways that separately involve the molecular constituents like endosomes, lysosomes, exosomes, neurotransmitters, etc. Inside the cell, constituents like water, chemicals, and ions are surrounded by the vesicles, which may draw out these molecules.
Difference Between Endocytosis and Exocytosis | Types, Mechanism, Function
The vesicles are small sacs that are enclosed in membranes, and they can surround a specific type of molecule and swallow it. These vesicles travel towards the cell membrane, and get attached to it. Common examples of exocytosis include secretion of pancreatic digestive enzymes, repairing wounds of the plasma membrane, discharge of neurotransmitter from presynaptic neurons, secretion of antibodies and peptide hormones, functions involving antigens during immunity body responses, etc.
Endocytosis In this process, the body cells ingest various molecules such as proteins, polar molecules, and other substances, through their hydrophobic plasma membrane. This process is carried out by many eukaryotic cells to ingest food particles by surrounding them, and in this case, the plasma membrane is extended outwards.
The basic mechanism of both the processes of exocytosis and endocytosis, is more or less the same. The phagosome is dragged to a lysosome. The fusion of lysosome with phagosome forms the phagolysosome.
What is the relationship between endocytosis and exocytosis? | Socratic
By the action of hydrolytic enzymes in the lysosome, the ingested material is digested. The destroying of foreign pathogens like bacteria and viruses in multicellular organisms by phagocytosis is involved in the defense of the organism.
Macrophages and neutrophils are considered as professional phagocytes. Phagocytosis Pinocytosis Receptor-mediated endocytosis occurs in pinocytosis, where fluids are taken up by the cell along with the dissolved solutes.
Clathrin-coated pits are the areas containing concentrated receptors on the plasma membrane. Specific receptors in these areas are bound with the macromolecules to be taken up. Pinocytosis is also called cell drinking. What is Exocytosis Exocytosis is the export of the material in the Golgi apparatus by secretory vesicles into the external environment.
The material in the Golgi apparatus is exported to transport vesicles. These vesicles travel to the plasma membrane and, the contents of the vesicles are released to the external environment with the fusion of plasma membrane.
Digestive enzymes and hormones are secreted out of the cell by exocytosis. Exocytosis is also involved in the elimination of waste from the cell.
Difference Between Endocytosis and Exocytosis
Two types of secretory pathways are involved in exocytosis: Constitutive Secretory Pathway Protein molecules in the Golgi apparatus, which are not tagged with signal peptides are secreted by the constitutive secretory pathway. The products, which are secreted out by the cell are stored in secretory vesicles. Since these vesicles contain a dense core, they are also called dense-core vesicles.
Small molecules like histamine and proteins like hormones and digestive enzymes are the products secreted by cells. Proteins which are destined for the secretion are called secretory proteins. Once these secretory proteins are loaded into secretory vesicles, they undergo post translational modifications like the liberation of active molecules by proteolysis. Regulated Secretory Pathway The secretion can be activated by extracellular signals as well.
This regulated exocytosis is called regulated secretory pathway. Histamine is secreted by mast cells, once a soluble stimulant called the ligand is bound to the receptors on the mast cells surface. Histamine leads to sneezing and itching, which are accompanied by allergic reactions.
Neurotransmitters are also secreted by the regulated secretory pathway. Endocytosis is involved in the up taking of substances from the external environment. Exocytosis is involved in the elimination of waste and secretion of contents in Golgi into the external environment. During endocytosis, an endocytic vesicle is formed surrounding the foreign substance, which is either a solid or a liquid.
During exocytosis, the vesicle containing the waste is fused with the plasma membrane in order to eliminate its contents.