Exocytosis and Endocytosis are methods for expelling and taking in a material using the cells membrane.
Endocytosis is a type of active transport (requires energy) that moves particles, such as large molecules, parts of cells, and even whole cells, into a cell. There are different variations of endocytosis, but all share a common characteristic: the plasma membrane of the cell forms a pocket around the target particle. The pocket pinches off, resulting in the particle being contained in a newly-created intracellular vesicle formed from the plasma membrane.
Phagocytosis is the process by which large particles, such as cells or relatively large particles, are taken in by a cell. The membrane from the body of the cell and surrounds the particle, eventually enclosing it creating a vesicle. Once the vesicle containing the particle is enclosed within the cell, the vesicle merges with a lysosome for the breakdown of the material in the newly formed compartment (endosome).
Pinocytosis means “cell drinking” and was named at a time when the assumption was that the cell was purposefully taking in extracellular fluid. In reality, this is a process that takes in molecules, including water, which the cell needs from the extracellular fluid. Pinocytosis results in a much smaller vesicle than phagocytosis.
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Online Flashcards Biology Question 19
• Endocytosis takes particles into the cell that are too large to passively cross the cell membrane.
• Phagocytosis is the taking in of large food particles, while pinocytosis takes in liquid particles.
• Receptor-mediated endocytosis uses special receptor proteins to help carry large particles across the cell membrane
• Exocytosis is the opposite of endocytosis as it involves releasing materials from the cell.
endocytosis: process that takes particles into the cell that are too large to passively cross the cell membrane
phagocytosis: “cell-eating”, takes up large molecules from the environment
pinocytosis: “cell-drinking”, takes up smaller molecules from the environment
receptor-mediated endocytosis: works like phagocytosis, relies on receptors to attract certain chemicals
exocytosis: process that removes particles from the cell
extracellular: outside the cell
active transport: the movement of substances against a concentration gradient using energy
vesicle: a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer
plasma membrane: the semipermeable barrier that surrounds the cytoplasm (inside contents) of a cell
lysosomes: a membrane-bound cell organelle that contains digestive enzymes
endosome is a membrane-bound compartment inside a eukaryotic cell