BIOL 1406 Lecture 7: Biology notes ch. 7
Document Summary
Chapter 7: membranes the boundary that separates the living cell from its surroundings. This semi-permeability is maintained in several different ways. Concept 7. 1: cellular membranes are fluid mosaics of lipids and proteins. The plasma membrane is composed of phospholipids and proteins. Phospholipids contain hydrophobic and hydrophilic regions that maintain a bilayer. The fluid mosaic model states that a membrane is a fluid structure with a mosaic of various proteins embedded in it. An ocean of phospholipids with islands of protein. A mosaic of proteins is dispersed within the bilayer. Membrane-proteins determine most of the membrane"s specific functions. Peripheral proteins are bound to the surface of the membrane. Integral proteins that span the membrane are called trans-membrane proteins. Diffusion is the tendency for molecules to spread out evenly into the available space. Molecules naturally try to diffuse in and out of cells. Cells are constantly fighting diffusion to maintain internal homeostasis.
