1. Active Transport
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2. conformational change
Active Transport
Cells may need to move molecules against concentration gradient
Uses protein “pumps”
shape change transports solute from one side of membrane to other
“costs” energy = ATP
conformational change
low
high
Some transport proteins do not provide channels but appear to actually translocate the solute-binding site and solute across the membrane as the protein changes shape. These shape changes could be triggered by the binding and release of the transported molecule. This is model for active transport.
ATP df
“The Doorman”
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3. Protein Pumps
“Pumps” are a special type of transport proteins called carrier proteins.
Carrier proteins are used to move substances against their concentration gradient (from areas of high concentration to areas of low concentration).
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4. More on Carrier Proteins
Carrier proteins bind to substances on one side of the membrane and release them on the other side.
REMEMBER: Carrier proteins are used in both passive and active transport. What is the difference?
Particles that are actively “pumped”: sodium, potassium, calcium, and hydrogen ions.
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5. Carrier Proteins
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6. Honors Biology

7. The Sodium-Potassium Pump
The Sodium-Potassium Pump admits ions needed for important biological processes
Pumps 3 sodium (NA+) out, and 2 potassium (K+) in
Both ions are being “pumped” against concentration gradient using ATP
Important for important glucose transport
Important for regulating water
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8. Sodium-Potassium Pump
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9. Transport Review Passive Transport Active transport ATP
Diffusion down concentration gradient (high  low)
Simple diffusion
diffusion of very small, nonpolar, hydrophobic molecules
Through membrane
high  low concentration gradient
Osmosis
Facilitated diffusion
diffusion of polar, hydrophilic molecules
through protein channels
Ion channels
Active transport
Diffusion against concentration gradient (low  high)
uses a protein pumps (Sodium-Potassium)
requires ATP
ATP
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10. Transport summary simple diffusion facilitated diffusion
ATP
active transport
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11. What about large molecules?
Moving large molecules into & out of cell
through vesicles & vacuoles
endocytosis
pinocytosis = “cellular drinking”
phagocytosis = “cellular eating”
exocytosis
exocytosis
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12. Endocytosis
The movement of a substance into a cell by a vesicle is called endocytosis.
There are two types of endocytosis:
1. Pinocytosis (liquids)
2. Phagocytosis (particles)
REMEMBER: Endo = In
REMEMBER: Pino = Drink
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13. Endocytosis
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14. Pinocytosis
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15. Phagocytosis
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16. Exocytosis
The movement of a substance by a vesicle to the outside of a cell is called exocytosis.
Used to export proteins that are modified by the Golgi apparatus.
REMEMBER: Exo = Exit!
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17. Exocytosis
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18. Exocytosis
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19. Special transport protein
Concept Map
Special transport protein
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