1. Chapter 4 Cells and Their Environment
Section 1
Passive Transport

2. Diffusion Passive process
Does not require energy
Caused by the random movement of particles
Moves DOWN the concentration gradient
From high concentration to low concentration
Ends in dynamic equilibrium
Small non-polar molecules are able to diffuse across the membrane

3. Diffusion animation

4. Osmosis The diffusion of water across a cell membrane
Follows all of the rules of diffusion
Based on the tonicity of the solutions on each side of the membrane

5. Osmosis continued Hypertonic- Higher concentration of solute
Pulls water toward
Shrivels cell
Hypotonic- Lower concentration of solute
Loses water
Cells swell and possibly burst (plasmolysis)
Isotonic- equal concentration of solute
No net movement of water

9. Osmosis Animation

10. Grape Lab p 76 Work in groups of 3
Each group member must make a lab to hand in
Follow the procedure 1-6 but we will use the following solutions
Grape juice
Sugar water
Distilled water
Tap water
Answer analysis ?’s 1-3

11. Needed to aid the passage of ions across the membrane due to their charge
Also referred to as transport proteins
Ion specific based on size and charge of the ion
May be opened and closed base on electrical charge (voltage gated channels)
Ions diffuse based on their concentration and due to charge (electrochemical gradient)
Data Lab p 79 in your notes
Ion Channels

12. Facilitated diffusion
Uses carrier proteins
Similar to ion channels
Molecule attaches to carrier causing a change in shape, and moves molecule to the inside
Rules of diffusion still apply (passive, high to low)

13. Facilitated Diffusion