Types of Types of TransportTransport

The various ways in which The various ways in which particles move in and out of particles move in and out of

cells!cells!

Passive TransportPassive TransportNo Energy is required!No Energy is required!

Moves Moves downdown a a concentration gradientconcentration gradient

(Particles move from high to low (Particles move from high to low concentration)concentration)

Three Types of Passive Transport:Three Types of Passive Transport:

Diffusion, Osmosis, & Facilitated Diffusion, Osmosis, & Facilitated Diffusion, ion channelsDiffusion, ion channels

What’s a Gradient?What’s a Gradient?

PassivePassive

PassiveHigh concentration

Low Concentration

DiffusionDiffusionDiffusion = net movement of particles from Diffusion = net movement of particles from

an area of high concentration to an area of an area of high concentration to an area of low concentration by low concentration by random motionrandom motion..

Molecules Reach EQUILIBRIUM: concentration Molecules Reach EQUILIBRIUM: concentration of a substance is the same throughout a of a substance is the same throughout a spacespace

. .

OsmosisOsmosis

Osmosis is the movement of Osmosis is the movement of waterwater from an area of high concentration to an from an area of high concentration to an area of lower concentration area of lower concentration

Solute:Solute: Substance that dissolves Substance that dissolves

Solvent:Solvent: Substance dissolving the solute Substance dissolving the solute

Hypertonic:Hypertonic: High amount of solutes High amount of solutes

Hypotonic:Hypotonic: Low amount of solutes Low amount of solutes

OsmosisOsmosis

(water moves to balance solution concentrations)

Another Example of Another Example of OsmosisOsmosis

Onion Cells in Hypotonic Solution Onion Cells in Hypertonic Solution

Facilitated DiffusionFacilitated DiffusionPASSIVE TRANSPORTPASSIVE TRANSPORT

Diffusion of a particle naturally down a Diffusion of a particle naturally down a concentration gradient using a concentration gradient using a carrier proteincarrier protein

Examples of Examples of Facilitated DiffusionFacilitated Diffusion

Receptor Mediated Facilitated Receptor Mediated Facilitated DiffusionDiffusion – a protein binds to a specific – a protein binds to a specific receptor on the cell membrane causing receptor on the cell membrane causing conformational changes of the associated conformational changes of the associated carrier protein which allows the transport carrier protein which allows the transport to the molecule to the other side of the to the molecule to the other side of the membrane.membrane.

Example: GlucoseExample: Glucose http://video.google.com/videosearch?hl=ehttp://video.google.com/videosearch?hl=e

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Ion ChannelsIon Channels

Small uncharged molecules can easily Small uncharged molecules can easily diffuse across cell membranes. However, diffuse across cell membranes. However, due to the hydrophobic nature of the due to the hydrophobic nature of the lipidslipids that make up cell membranes, water-that make up cell membranes, water-soluble molecules and ions cannot.soluble molecules and ions cannot.

Ion Channels are Ion Channels are hydrophilic thus hydrophilic thus allowing other polarallowing other polar molecules to pass molecules to pass through easily. through easily.

Active TransportActive TransportEnergy Energy ISIS required required

Particles are being moved Particles are being moved AGAINSTAGAINST a a concentration gradientconcentration gradient

(Particles move from low concentration to (Particles move from low concentration to high concentration)high concentration)

Three Types of Active Transport:Three Types of Active Transport:

Protein Pumps, Endocytosis & Protein Pumps, Endocytosis & ExocytosisExocytosis

ActiveActive

ActiveHigh concentration

Low Concentration

Sodium-Potassium PumpSodium-Potassium Pump Proteins that use ATP

to carry molecules against a concentration gradient

Na+ out/K+ In Function of Na+/K+

Pump:– Creates an

electrochemical gradient (action potential) sends nerve pulses

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EndocytosisEndocytosisCell ingests large macromolecules or other cells

Vesicle

ExocytosisExocytosisOpposite of EndocytosisRelease of contents in the cell to the external environment

Vesicle