Biology 2581B Study Guide - Quiz Guide: Endoplasmic Reticulum, Secretion, Cell Membrane
15 May 2020
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Exocytosis vs. endocytosis (a) in exocytosis, a transport vesicle fuses with the plasma membrane. Its content is released into the extracellular space, while the vesicle membrane (red) becomes continuous with the plasma membrane. For newly formed proteins, carbohydrates, lipids. (b) in endocytosis, a plasma membrane patch (red) is internalized, forming a transport vesicle. For recovering plasma membrane components, delivered to endosomes, after which they can be recycled or delivered to lysosomes for degradation. (fig. This vesicular traffic flows along highly organized, directional routes, which allow the cell to secrete, eat, and remodel its plasma membrane and organelles. The secretory pathway leads outward from the endoplasmic reticulum (er) toward the golgi apparatus and cell surface, with a side route leading to lysosomes, while the endocytic pathway leads inward from the plasma membrane. In each case, retrieval pathways balance the flow of membrane between compartments in the opposite direction, bringing membrane and selected proteins back to the compartment of origin.
