1. Notes: Movement of Material Across the Cell Membrane Active Transport
Active Transport- requires energy to get material across a cell membrane against a concentration difference (or gradient).
Substances are forced to move from an area of lower concentration into an area of higher concentration (into a place that is already more crowded).

3. There are several different forms of Active Transport:
Pump- a special type of carrier protein that is used to push molecules from an area of low concentration into an area of high concentration.
Ex. Sodium (Na+) and Potassium (K+)
-The carrier protein pumps three Na+ ions out of the cell and then picks up two K+ ions and pumps them into the cell across the membrane
-The pump uses ATP for energy
-This unequal exchange of ions creates a charge (which the cell uses to send signals from one cell to another).

4. 2. Endocytosis- taking material into the cell, usually by forming pockets around the material (the cell membrane folds around something in the external environment of the cell).

5. A. Phagocytosis- intake of large particles or cells (solid material) through the cell membrane within a vesicle.

6. B. Pinocytosis- using a vesicle or pocket to take in liquid or dissolved substances (solutes).

7. 3. Exocytosis- A vesicle made by the cell when it fuses with the cell membrane, releasing their contents into the external environment.