1. Active Transport of Substances Into A Cell

2. Active Transport What type of material is transported?
materials needed by the cell that are in low concentrations outside the cell.
AND/OR solutes that normally don’t diffuse through the membrane
Type of transport
active
Energy requirement
ATP!!!

3. Molecular Active Transport
Direction of transport
against the gradient – from low to high concentration
Requires transport protein:
a) Transports a specific solute.
b) ATP energy is needed to change the shape of the transport protein so it can transport the solute.

4. Molecular Active Transport
Advantage:
cell interior can maintain high concentrations of important solutes even when they are in short supply in the environment. (like a camel’s hump)
For example…
Movement of Calcium, Potassium, or Sodium ions across the cell membrane

5. Molecular Active Transport
Small molecules and ions are carried across the cell membrane by special proteins in the membrane that act like pumps and change their shape to move molecules into/out of the cell

6. Transport (carrier) protein
Solute
Binding site
Outside of Cell
low solute concentration
Inside of Cell
High solute concentration
Transport (carrier) protein
ATP energy
used
Solute

7. Why does Molecular Active Transport need ATP?
Moving a solute from an area of LOW concentration to an are of HIGH concentration
This goes AGAINST the gradient

8. BULK ACTIVE TRANSPORT
EXOCYTOSIS - Process of moving large materials out of the cell ENDOCYTOSIS - Process of moving large materials into the cell (Engulfing)
NOTE - Due to the large changes made to the cell membrane, this is also a form of active transport and ATP is required.

9. Endocytosis
Exocytosis

10. BULK ACTIVE TRANSPORT: Endocytosis and Exocytosis
What type of material is transported?
large molecules like proteins, wastes, polysaccharides, entire organisms, damaged cells, hormones
Type of transport
Active
Energy requirement
ATP!!!
Direction of transport
Exocytosis – OUT Endocytosis - IN

11. membrane forms a pocket around particles
Endocytosis
membrane forms a pocket around particles
2) pinches off to form a vesicle or vacuole
3) moves to interior of cell
4) Some cells use this method to engulf large molecules, food, or other cells.

12. Types of Endocytosis Phagocytosis Pinocytosis
Extensions of cytoplasm surround a particle and package it within a food vacuole
Example:
Amoeba engulfing food
A cell may take up liquid from its environment
Tiny pockets form along the cell membrane, fill with liquid, pinch off to form vacuoles within the cell

13. Exocytosis 1) particle moves to the cell membrane
2) vesicle joins to cell membrane
3) particle is released to cell environment
4) Example
Contractile vacuoles in unicellular freshwater protists help rid them of excess water

14. GOOD VIDEO LINK!

15. Bulk Transport Requires:
Changes in large segments of the cell membrane. These changes are triggered by proteins in the cell membrane that signal the membrane to change.
Advantages:
1)  moves large materials that can’t diffuse
2)  allows single celled organisms to engulf food directly from environment
3) allows movement of large proteins produced by the cell to exit (insulin, growth hormones)

16. ACTIVE TRANSPORT SUMMARY

18. Online Review Log In to pearsonsuccessnet.com
Go to the Interactive Digital Path
Go to Unit 3  Chapter 7  Section 3  View
Click on the orange “Activities” Tab
Complete BOTH the “Art in Motion” and the “InterActive Art”