Active Transport of Substances Into A Cell

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 concentrationsoutside 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 likepumpsand 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. 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. BULK ACTIVE TRANSPORT

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. 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. Pinocytosis Types of Endocytosis Phagocytosis Extensions of cytoplasm surround a particle and package it within a food vacuole Example: Amoeba engulfingfood 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! HTTP://WWW.LINKPUBLISHING.COM/VIDEO-TRANSPORT.HTM#PARAMECIUM_-_CONTRACTILE_VACUOLES

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”