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 ChannelsIon 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 energyActive 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 cellSodium-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 membraneEndocytosis
10 During exocytosis substances inside a vesicle are released from a cell as the vesicle fuses with the cell membraneExocytosis
11 Communications between Cells Communication between cells often involves signal molecules that are bound by receptor proteinsCommunications between Cells