2. Work in pairs to make your model. (source: http://www.education.com/science- fair/article/build-cell-membrane- model/?coliid=1012059) http://www.education.com/science- fair/article/build-cell-membrane- model/?coliid=1012059

3. Fluid Mosaic Model: http://www.youtube.com/watch?v=Qqs f_UJcfBc&safety_mode=true&persist_sa fety_mode=1&safe=active http://www.youtube.com/watch?v=Qqs f_UJcfBc&safety_mode=true&persist_sa fety_mode=1&safe=active Transport Across a Cell Membrane: http://www.youtube.com/watch?v=2UP qLm- uDnI&feature=related&safety_mode=tr ue&persist_safety_mode=1&safe=active http://www.youtube.com/watch?v=2UP qLm- uDnI&feature=related&safety_mode=tr ue&persist_safety_mode=1&safe=active

4. Review Assessment Draw and label a sketch of the cell membrane with as many parts as you can remember.

5. Functions of Cell Walls and Membranes Cell membrane: regulates what enters and leaves the cell, and provides protection and support – Lipid bilayer: (diagram this) – A semi-permeable membrane Cell walls: support and protection

6. Types of Transport Across a Cell Membrane 1.Passive transport 2.Active Transport

7. 1. Passive Transport Passive transport: – requires no energy (action or effort) from the cell – occurs DOWN a concentration gradient (particles move from areas of higher concentration --- more “crowded” --- to areas of lower concentration – occurs until concentrations are equal on both sides of the membrane (“equilibrium”) – Three types:

8. 1.Diffusion: occurs strictly due to concentration 2.Facilitated diffusion: requires a protein channel for passage 3.Osmosis: diffusion of water

9. Osmosis Through a Semi-permeable Membrane

10. Concentrations (and “Gradients”) Def: mass of solute (“particles”) per volume of solution – Example: How many grams of sugar in a gallon of tea? Isotonic: “same strength”; both solutions are the same strength. – Which way would solutes move? Water? Hypertonic: a higher concentration solution than another Hypotonic: ???

11. Effects of Osmosis on Cells

12. Homework Assignment: Design an Experiment Analyzing Data: Crossing the cell membrane (p.188) Answer the questions completely, INCLUDING designing an experiment. Be sure to include all equipment/supplies and procedure steps.

13. 2. Active Transport Active Transport: – occurs AGAINST (or “up”) a concentration gradient (from areas of lower concentration to areas of higher concentration) – requires energy – Is equilibrium of concentrations reached?

14. 1.Molecular transport: protein pumps carry small molecules and ions across the membrane 2.Endocytosis: taking materials into the cell by means of infoldings, or pockets, of the cell membrane. 3.Exocytosis: ????? – The membrane of a vacuole containing material fuses with the cell membrane and forces the contents out of the cell.

15. 1.Phagocytosis: – “_____ eating” – Extensions of cytoplasm surround a particle and package it within a food vacuole to be taken into the cell. 2.Pinocytosis: tiny pockets along the cell membrane fill with liquid and pinch off to form vacuoles within the cell