1. Active Transport Joohee Kim Sec. III IB Biology

2. Active Transport  Active transport is the pumping of molecules against their concentration gradient with the expenditure of energy (ATP).

3. Why Is It Necessary?  Living cells often require the uptake of molecules that are scarce in their environment.

4. 3 Types Of Active Transport  Ion Pumps  Cotransport  Endocytosis

5. Ion Pumps  Ion pumps (also called electrogenic pumps) are special proteins which actively transport ions resulting in an ionic and voltage gradient.

6. Cotransport  Cotransport is the coupled passage of two materials across a membrane.  Without assistance, the sucrose is unable to enter the cell.

7. Endocytosis  Endocytosis is the import of materials to the cell by infoldings of the plasma membrane.

8. Phagocytosis (cell eating)  In Phagocytosis, pseudopods (extensions of the cell membrane) surround the food item and fuse together forming a vesicle to take the food into the cell.

9. Pinocytosis (cell drinking)  In Pinocytosis, vesicles of fluid are formed in the cell membrane without the formation of pseudopods.

10. Receptor-Mediated Endocytosis  In receptor- mediated Endocytosis, special coated pits in the cell membrane are lined with receptor proteins that binds with specific materials.