Endocytosis is the process that a cell uses to take in molecules from the extracellular space by folding its membrane around it forming a vesicle/vacuole. The cell engulfs some of its extracellular fluid (includes materials dissolved or suspended in it. A portion of plasma membrane is coated with the protein clathrin and pinched off forming a vesicle called endosome. The endosome also removes dead or damaged cells from the body and is a defense against microorganism. Eukaryotic cells internalize fluid, large and small molecules, and even other cells from their surrounding by this process. The plasma membrane of the cell forms a pocket around the material to be internalized and the pocket closes and separates from the inside surface of the plasma membrane to form a membrane vesicle, containing the ingested material.
There are two main types of endocytosis, pinocytosis and phagocytosis. Pinocytosis means “cell drinking”. It occurs in all cells and occurs continuously. It describes the internalization of extracellular fluid and small macromolecules by means of small vesicle. It begins with small, convex pits on the cell surface that collects material or fluid to be internalized. Convexed pits expand into the interior of the cell forming small vesicles that pinch from the inside of the plasma membrane. The eukaryotic cells have continuous stream of vesicles budding from the plasma membrane. The constant removal of membrane from the plasma membrane will quickly deplete the plasma membrane if it wasn’t for exocytosis. Pinocytosis brings fluid and material into the cell and removes membrane from the plasma membrane. Exocytosis expels fluid and material from the cell adding membrane to plasma membrane.
The other type of endocytosis is phagocytosis. This means “cell eating” and results in ingestion of particulate matter like bacteria from the extracellular. Endocytosis gets so large it is called a vacoule/ phagosome. It occurs to specialized cells like amoeba and occurs sporadically. While all eukaryotic cells are continuously are continuously ingesting fluid and molecules by pinocytosis, only specialized phagocytic cells ingest large particles.
These large particles it usually engulfs can be another cell, like a white blood cell. Since its part of the immune system, it can destroy the bacteria that are engulfed by the cell. Cells that engages in phagocytosis is called phagocyte. White blood cells have to recognize the invader so it could destroy it. It recognizes the signal molecules released from the bacterium and the white blood cell is drawn to it. It attaches its membrane to the bacterium on the membrane using surface receptors. Molecules are imbedded in to the white blood cell membrane and are designed to detect and attach molecules in membrane of the bacterium. The two cell membrane link up and stick together and once attached, the membrane of the white blood cell surrounds around the bacterium and engulfs it. The membrane encloses the bacteria and pinches off creating a pouch called phagosome. After the bacteria is safely kept in the white blood cell it could be destroyed. The white blood cell inserts its digestive enzymes into the phagosome and it breaks down the bacterium. The results to harmless particles and can be used by cell or released by cell.
There are two main types of endocytosis, pinocytosis and phagocytosis. Pinocytosis means “cell drinking”. It occurs in all cells and occurs continuously. It describes the internalization of extracellular fluid and small macromolecules by means of small vesicle. It begins with small, convex pits on the cell surface that collects material or fluid to be internalized. Convexed pits expand into the interior of the cell forming small vesicles that pinch from the inside of the plasma membrane. The eukaryotic cells have continuous stream of vesicles budding from the plasma membrane. The constant removal of membrane from the plasma membrane will quickly deplete the plasma membrane if it wasn’t for exocytosis. Pinocytosis brings fluid and material into the cell and removes membrane from the plasma membrane. Exocytosis expels fluid and material from the cell adding membrane to plasma membrane.
The other type of endocytosis is phagocytosis. This means “cell eating” and results in ingestion of particulate matter like bacteria from the extracellular. Endocytosis gets so large it is called a vacoule/ phagosome. It occurs to specialized cells like amoeba and occurs sporadically. While all eukaryotic cells are continuously are continuously ingesting fluid and molecules by pinocytosis, only specialized phagocytic cells ingest large particles.
These large particles it usually engulfs can be another cell, like a white blood cell. Since its part of the immune system, it can destroy the bacteria that are engulfed by the cell. Cells that engages in phagocytosis is called phagocyte. White blood cells have to recognize the invader so it could destroy it. It recognizes the signal molecules released from the bacterium and the white blood cell is drawn to it. It attaches its membrane to the bacterium on the membrane using surface receptors. Molecules are imbedded in to the white blood cell membrane and are designed to detect and attach molecules in membrane of the bacterium. The two cell membrane link up and stick together and once attached, the membrane of the white blood cell surrounds around the bacterium and engulfs it. The membrane encloses the bacteria and pinches off creating a pouch called phagosome. After the bacteria is safely kept in the white blood cell it could be destroyed. The white blood cell inserts its digestive enzymes into the phagosome and it breaks down the bacterium. The results to harmless particles and can be used by cell or released by cell.
These are the different types of endocytosis. We talked about the pinocytosis and phagocytosis mostly. Pinocytosis means cell drinking and occurs in most cell and happened continuously. The cell membrane will allow the fluid it wants to take in to push inwards, causing a divot in the membrane. The fluid fills into the divot and the bend gets larger. Eventually, the membrane pinches it off, trapping the fluid inside the vesicle, which is now inside the cell. Phagocytosis means cell eating. It usually results in ingestion of particulate matter like bacteria from the extracellular. Endocytosis gets so large it is called vacuole/ phagosome and only occurs to specialized cells like amoeba and occurs sporadically. It engulfs particles like white blood cells and bacterium. White blood cells are attracted to the bacterium and attach itself on it. It then inserts digestive enzymes into it. Then the white blood cell the surround the bacterium and engulfs it. It then breaks it down to harmless particles.
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