BIOL 1107 Chapter Notes - Chapter 6: Facilitated Diffusion, Electrochemical Gradient, Spontaneous Process
Document Summary
Chapter 6 - lipids, membranes, and the first cells. The plasma membrane ,or cell membrane, separates life from nonlife. It is a layer of molecules that surrounds the cell interior and separates it from the environment. The plasma membrane serves as a selective barrier: it keeps damaging compounds out of the cell and allows entry of compounds needed by the cell. Because the plasma membrane sequester the appropriate chemicals in an enclosed area, reactants collide more frequently - the chemical reactions necessary for life occur much more efficiently. Lipid is a catchall term for carbon-containing compounds that are found in organisms and are largely nonpolar and hydrophobic (does not dissolve readily in water). Lipids do dissolve in liquids consisting of nonpolar organic compounds. Lipids are insoluble to water because it consists of carbon atoms bonded to hydrogen atoms. Molecules that contain only carbon and hydrogen are known as hydrocarbons.
