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Passive and Active Transport

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Presentation on theme: "Passive and Active Transport"— Presentation transcript:

1 Passive and Active Transport
Movement of material into and out of cells

2 Passive transport is the movement of substances across the cell membrane without the use of energy by the cell

3 Diffusion is the movement of a substance from an area of high concentration to an area of lower concentration

4 Osmosis is the diffusion of free water molecules across a selectively permeable membrane.

5 Ion Channels Ion channels are proteins that have a pore through which ions can cross the cell membrane. Ions cannot diffuse across the cell membrane due to the lipid bi-layer. Ion channels move ions from an area of high ion concentration to an area of low ion concentration (down the ion’s concentration gradient).

6 Facilitated Diffusion
In facilitated diffusion, a carrier protein transports a substance across the cell membrane down the concentration gradient of the substance

7 Active transport is the movement of a substance against the concentration gradient of the substance. Active transport requires cells to use energy Active Transport

8 Sodium-Potassium Pump
In animal cells, the sodium-potassium pump uses energy supplied by ATP to transport sodium ions out of the cell and potassium ions into the cell Sodium-Potassium Pump

9 Endocytosis Click for video of Endocytosis and Exocytosis
During endocytosis, substances are moved into a cell by a vesicle that pinches off from the cell membrane Endocytosis

10 During exocytosis substances inside a vesicle are released from a cell as the vesicle fuses with the cell membrane Exocytosis

11 Communications between Cells
Communication between cells often involves signal molecules that are bound by receptor proteins Communications between Cells


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