ASCI 112 Lecture Notes - Lecture 6: Exocytosis, Phospholipid, Phagocytosis
Document Summary
Transport across membrane: movement of water & nutrients into a cell or elimination of wastes out of cell. 1: membrane folding (endocytosis & exocytosis, diffusion/osmosis. Lipids are a majority of the structure but proteins give membrane function. Only certain things are allowed to pass through membrane. Bulky substances combined w/in secretory vesicles are moved into and out of a cell via the cell membrane (aka plasma membrane) Endocytosis: engul ng of substances outside of cell to form vesicle brought inside cell. Exocytosis: discharge of substances from vesicles at inner surface of cell. Diffusion: molecules move in random fashion, move from high concentration to an area of low concentration, molecules move down a concentration gradient from higher to lower concentrations. Osmosis: water moves down its concentration gradient into or out of a cell, movement of water is dependent on concentration of other substances. Rule: water will move to areas of higher solute concentration: requires semipermeable membrane.
