BI110 Study Guide - Final Guide: Fluid Compartments, Passive Transport, Cell Membrane
Document Summary
Passive transport (movement along concentration gradient: simple diffusion, osmosis. Active transport (movement against concentration gradient: passive transport. Diffusion - net movement of a substance from region of higher to lower concentration. Primary mechanism of solute movement within a cell and between cellular compartments separated by a membrane. The rate of diffusion depends on the concentration difference of two sides of the membrane (concentration gradient) The concentration gradient itself is a form of potential energy and as the molecule moves from area of high to low concentration - it is giving up energy. Because giving up less energy to reach equal distribution. Every molecule has thermal energy (are moving a little bit), therefore there"s a random motion - move from high concentration areas to low areas. Passive transport means that atp is not used to drive the movement. Molecule is diffusion with its gradient (high to low)