1. Cell Membrane IS3

2. Functions Protects the cell Semi-permeable barrier: selects incoming and outgoing substances (passive/active transport) Maintain concentration of various substances Allows cell recognition/communication Allows receptivity (hormones, etc) Allows the cell to maintain its shape Helps compartmentalize subcellular domains Phospholipids are a major component of cell membranes.

3. Fluid Mosaic Model (1972) - Phospholipid bilayer with proteins forming a mosaic pattern as they float/penetrate through the membrane Hydrophilic end: phosphate = polar Hydrophobic end: fatty acid = non-polar

4. Credit: Stephen Taylor

6. Transport through membranes Active: ATP needed / proteins are used as pumps to move substances against the concentration gradient. Passive: no ATP needed / small particles cross the membrane through special proteins or lipid bilayer

7. Passive Transport Diffusion: movement of particles through the lipid bilayer from an area of high concentration to an area of low concentration O2, H2O, urea, glycerol, CO2 Facilitated Diffusion: diffusion of particles through special transport proteins charged molecules (even small ones) and large uncharged molecules Na+, K+, glucose

12. Hypertonic: The solution with the higher concentration of solutes.

13. Hypotonic: The solution with the lower concentration of solutes.

15. The K+/Na+ Pump: An example of Active Transport Essential for the nerve impulse to be produced The pump is an integral membrane protein Cellular [K+] is high and [Na+] is low Protein pumps K+ in and Na+ out This pump works independent of concentration gradient K+/Na+ Pump

16. Types of transport

17. Endocytosis/Exocytosis Endocytosis: ingesting... particles = phagocytosis liquids = pinocytosis Exocytosis: releasing particles/waste http://www.maxanim.com/physiology/Endocytosis%20and%20Exocytosis/Endocytosis%20and%20Exocytosis.htm

18. Describe what is happening and the structures involved - - - - 4 X 3 2 1