1. Movement of substances through the cell membrane.

2. Passive movement of substances through the cell membrane (no cellular energy required)
Diffusion: The process by which molecules or ions scatter or spread spontaneously from regions of high concentration to low concentration.
What happens to the candy when it is placed in water?
diffusion video

3. Passive Movement
2.Facilitated diffusion: When molecules such as sugar are too large to pass through the pores of the cell membrane, carrier molecules carry the large molecules from regions of higher to areas of lower concentration. facilited diffusion video

4. Passive Movement
3. Filtration: Movement of molecules across a membrane as a result of pressure
play video
Summary

5. 4. Osmosis: A special case of diffusion in which water molecules diffuse from regions of higher concentration to area of lower concentration.
Play Osmosis Video

6. What do you think will happen to red blood cells when the are placed in a hypertonic solution? Watch the video.

7. What do you think will happen to red blood cells when the are placed in a hypotonic solution? Watch the video.

8. Active Mechanisms (Use cellular energy)
Active transport -process that moves particles through membranes regions of lower concentration to regions of higher concentration. animation and quiz

9. ACTIVE TRANSPORT 1. Sodium Potassium Pumps
Uses specific carrier molecules (pumps)
Uses 40% of the cell’s energy
Particles transported include sugars, amino acids, sodium, potassium, calcium and hydrogen ions
amazing students

11. 2. Endocytosis- large particles are brought into a cell through vesicles
a. pinocytosis- cell
takes in liquids
b. phagocytosis- cell
takes in solids
c. receptor mediated
-specific molecules
move into cell
3. Exocytosis- a substance stored in a vesicle is released from the cell Animation

12. Summary
Passive transport- the cell does not expend energy 1. diffusion -movement of molecules -no force 2. osmosis -diffusion of water molecules 3. filtration -filter present -force

13. Summary Active transport- the cell uses energy to move molecules
Cell membrane pumps
- Proteins in the cell membrane
pump ions across the concentration gradient
2. endocytosis
-cell engulfs solids or liquids
3. exocytosis
-cell releases substances