BIOL 1010 Lecture Notes - Osmoregulation, Pseudopodia, Phagocytosis
Document Summary
Membranes: membranes are of fundamental importance to life, membranes are the defining boundaries of cells. Membranes permit development of an aqueous solution inside the cell (some say the inside of a cell is an aqueous gel) that is different in composition from the surrounding environment. The membrane accomplishes this while still allowing movement of nutrients into the cell and wastes out of the cell: membranes have selective permeability - some substances cross the membrane more easily than others. These proteins are very specific and selective in what they will transport. First observed membrane structure with an electron microscope in the 1950s (recall resolving power of microscopes) Fluid mosaic model currently accepted membrane model proposed by s. j. Singer and g. nicolson (1972) as a modification to the original davson-danielli sandwich (1935) (cid:0) membrane components are arranged in a phospholipid bilayer (recall: the amphipathic nature of phospholipids) and held together by hydrophobic interactions.
