Cell Structure and Function

Movements Across Plasma Membranes  phospholipase  Molecular MovementsIn and Out of Cells  2 Types: 1. Transports that do not require energy 2. Transports that require energy  Transports That Do Not Require Energy: Passive Transport    Does not require input of energy Molecules pass through membrane from an area of high concentration to an area of low concentration 2 Types:  Simple Diffusion  Facilitated Diffusion  1. Simple Diffusion     Small molecules pass through the phospholipid bilayer No energy needed Movement: high concentration to low Examples: CO2, O2, H20 diffusion  2. Facilitated Diffusion     Molecules pass through a transport protein No energy needed Movement: high concentration to low facilitated diffusion Example: Glucose  Energy Requiring Transport   Molecules move from an area of low concentration to an area of high concentration. “against the gradient” 3 Types:  Active Transport  Endocytosis  Exocytosis  1. Active Transport     Carrier protein in membrane attaches to a specific molecule Carrier protein changes shape as molecules crosses the membrane Energy is required Example: + + K ,Na ions active transport