1. Transport Across Membranes

2. Transport Across Membranes Passive Transport
Examples of Passive Transport
Cells and Osmosis
Active Transport
Comparing Passive and Active Transport

3. Passive Transport
Passive Transport: movement of molecules across a membrane from an area of high concentration to an area of low concentration.
Passive Transport does not require energy.
Three types:
Diffusion
Osmosis
Facilitated Diffusion

4. Examples of Passive Transport
1) Diffusion: the movement of any particle from high to low concentration.
Glue this picture beneath your definition, Label the areas of high and low concentration, then shade them two different colors.

5. Examples of Passive Transport
2) Osmosis: the movement of water from high to low concentration.
Glue this picture beneath your definition, Label the areas of high and low concentration in each picture, then shade them two different colors.

6. Examples of Passive Transport
3) Facilitated Diffusion: movement of large molecules from high to low through transport proteins.
Glue this picture beneath your definition, Label and shade the areas of high and low concentration, and the transport (carrier) proteins.

7. Cells and Osmosis
Hypotonic—water moves into the cell High Low. Therefore cell swells.
Isotonic—water moves in and out of cell because there is no concentration difference. Therefore cell does not change.
Hypertonic—water moves out of cell High Low. Therefore cell shrivels.

8. Cells and Osmosis
In animal cells, hypotonic conditions can lead to lysis, cells bursting.
In plant cells, hypotonic conditions provide the water pressure needed to support the cell wall.
In plant and animal cells, hypertonic conditions cause cells to shrivel (this is why plants wilt when not watered).

9. Active Transport
Active transport: movement of molecules from an area of low concentration to an area of high concentration.
Active transport uses membrane proteins that require energy (ATP).
Glue down the picture, then label and shade:
Areas of high &
low concentration
Membrane
proteins
ATP

10. Active Transport
Endocytosis: uses lots of energy to move particles inside the cell.
Exocytosis: uses lots of energy to move particles outside the cell.
Endocytosis
Exocytosis

11. Comparing Active & Passive Transport
In the top portion of the flap, draw a Venn diagram. Label one circle Active Transport and the other Passive Transport.
Place the words from the chart below into the appropriate places on the Venn diagram.
Uses energy
No energy required
Osmosis
Diffusion
Semi-permeable membrane
With a gradient
High  Low
Low  High
Movement of particles
Facilitated diffusion
Exocytosis
Membrane protein
Against a gradient
Endocytosis
ATP

12. Comparing Active & Passive Transport
High
Active Transport
Low to High
Uses Energy
Passive Transport
High to Low
No Energy
Low