1. Warm Up Write your responses in your binder:
What materials need to get into a cell? Why?
What materials need to get out of a cell? Why?
What cell structure must these materials pass through?

2. Activating Activity…
Gobstopper activity:

3. Gobstoppers Activity What happened: Why it happens:
The water dissolves the colorful sugar candy coating. Compounds, such as the sugar and food dye, mix into the water, making a solution. You can see the dye diffusing outward, away from the candies. When two different colored dye fronts encounter one another, instead of mixing, they remain mostly distinctly different colors. A line forms with one color on one side and another color on the other side. Eventually, after several minutes, mixing will occur.
 Why it happens:
The dye molecules are relatively large and massive, especially compared with small molecules like H2O. The dye molecules from each dye color run into one another and their rates of diffusion slow because the big molecules of each color move more slowly around one another than they do through smaller particles like water. Eventually, diffusion and mixing of the dyes does happen.

4. Exchange With the Environment
Movement of Materials
Into and Out of Cells

5. Foldable:
Passive Transport
Active Transport
Cellular Transport

6. Cellular Transport Remember: All living things use energy.
So, materials such as food, water, and oxygen need to get into cells.
Additionally, wastes, such as carbon dioxide, needs to get out of cells.
Homeostasis – the maintenance of stable internal conditions inside of the cell

7. The Cell Membrane
The exchange of materials between the cell and its environment takes place at the cell’s membrane.
Selectively permeable (or semipermeable) – selects or chooses what materials may pass through (or permeate)
Two general types of cellular transport:
Passive transport
Active transport

8. I. Passive Transport Two types:
Passive transport is the movement of materials through the cell membrane WITHOUT the use of energy.
Two types:
Diffusion
Osmosis

9. 1. Diffusion
Diffusion
The movement of small particles through the cell membrane from areas of high concentration (crowded) to areas of low concentration (less crowded).
Particles are constantly moving
Does NOT require that the cell use any energy
Cell
membrane
over time…

10. Area of higher concentration Area of lower concentration

11. Diffusion
Before diffusion – particles are crowded outside the cell and some move into the cell.
After diffusion– particles have reached equilibrium.

12. Facilitated Diffusion (Accelerated)
Some substances, such as glucose (a sugar) cannot move through the phospholipid cell membrane.
They are “helped” through the cell membrane by carrier proteins.
Animation

13. 2. Osmosis
Diffusion of water is so important to life processes that it has been given a special name…Osmosis – the diffusion of water (Think…H20 = osmosis)
Water is made up of particles, called molecules (H2O).
Pure water = has a higher concentration of water molecules
Mixture in water (solution) - has a lower concentration of water molecules
Ex: food coloring, sugar, or salt mixed in water

14. Osmosis

15. Affect of Water on Red Blood Cells
Normal
Salt water
Too much “pure” water

16. Warm Up
The cell membrane of this cell is permeable to water but not to dissolved materials (solutes). What will immediately happen when the cell is placed into this solution?
Water will flow out of the cell.
Water will flow into the cell.
Dissolved materials will move into the cell.
Dissolved materials will move into the cell AND water will move out.
= dissolved materials

17. II. Active Transport
When cells use energy to move materials through the cell membrane, it is called active transport.
Movement of small molecules from LOW to HIGH concentrations (LESS CROWDED to CROWDED areas).
Movement of large molecules into or out of the cell.

18. Moving Small Particles
Movement from LOW to HIGH concentrations of a substance
Special proteins “pump” (or push) materials through the cell membrane.
Ex: sodium

19. Moving Large Particles
Large particles move into and out of cells through:
Endocytosis – cell surrounds a large particle and encloses the particle in a vesicle to bring the particle into the cell.
Vesicle – sacs formed from pieces of the cell membrane
Endo = inside
Exocytosis – when large particles leave the cell through the cell membrane
Exo = exit; outside

20. ENDOCYTOSIS - into
EXOCYTOSIS – out of

21. TOC #36 “Cellular Transport Analogy Chart”
Characteristic
Passive Transport
(Diffusion & Osmosis)
Active Transport
(Transport proteins, endocytosis, exocytosis)
Molecule Movement
High to Low
(crowded to less crowded)
1. Low to High
(less crowded into a crowded area)
2. Large particles
Uses
Energy? No
Yes
Analogies
Rowing with the current
Rowing against the current
Cycling downhill
Cycling uphill

22. Cellular Transport Review WS
BrainPop Video
Handout