1. “Active” Cellular Transport
Requires energy
cellular energy = ATP
Moves materials from LOW to HIGH concentration
Works AGAINST concentration gradient

2. Three Types of Active Transport
Membrane Pumps
2. Endocytosis (pinocytosis and phagocytosis)
3. Exocytosis

3. 1. Membrane Pumps Against gradient Uses transport proteins
Specific binding sites
Activated by ATP

4. The Membrane Pump ATP activates protein Molecules bind
Transported to other side
Protein returns to original shape
Remember ATP is the energy used to power cellular reactions.

5. Membrane Pumps - Example
The Plasma Membrane
11/12/2018
Membrane Pumps - Example
Sodium-Potassium Pump
Na+ (sodium ions) are pumped out and K+ (potassium ions) are pumped in against strong concentration gradients.
G. Podgorski, Biol. 1010

6. Sodium-Potassium Pump
The Plasma Membrane
11/12/2018
Sodium-Potassium Pump
3 Na+ are pumped in for every 2 K+ pumped out (both AGAINST the gradient). Creates a membrane potential and regulates cell volume
G. Podgorski, Biol. 1010

7. 2. Endocytosis
Uses energy to form a vesicle by folding the membrane inward
Moves food, large amounts of water, and other molecules to the inside of the cell

8. Receptor-Mediated Endocytosis
The Plasma Membrane
11/12/2018
Receptor-Mediated Endocytosis
Some integral proteins have receptors on their surface to recognize & take in hormones, cholesterol, etc.
G. Podgorski, Biol. 1010

10. Two Types of Endocytosis
Eating (Phagocytosis)
Drinking (Pinocytosis)
Takes in food
Uses energy
Takes in water/liquids
Uses energy

11. Endocytosis – Phagocytosis
The Plasma Membrane
11/12/2018
Endocytosis – Phagocytosis
Used to engulf large particles such as food, bacteria, etc. into vesicles
Called “Cell Eating”
G. Podgorski, Biol. 1010

13. The Plasma Membrane
11/12/2018
Phagocytosis - Capture of a Yeast Cell (yellow) by Membrane Extensions of an Immune System Cell (blue)
G. Podgorski, Biol. 1010

14. Pinocytosis Most common form of endocytosis.
The Plasma Membrane
Pinocytosis
11/12/2018
Most common form of endocytosis.
Takes in dissolved molecules as a vesicle.
G. Podgorski, Biol. 1010

15. 3. Exocytosis Cell expelling wastes Opposite of endocytosis
Uses energy, against gradient

16. The Plasma Membrane
11/12/2018
Exocytosis The opposite of endocytosis is exocytosis. Large molecules that are manufactured in the cell are released through the cell membrane.
Cell environment
Inside Cell
G. Podgorski, Biol. 1010

17. Review: Types of Transport
Passive
Diffusion
Osmosis
Facilitated diffusion
Active
Membrane pump
Endocytosis
Pinocytosis
Phagocytosis
Exocytosis