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Keep on Movin On!

3.8 Describe Active Transport

3.9 Determine what factors impact whether a substance will passthrough a membrane.

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Review

We have gone over many different kinds ofpassive transport.

Do you remember what they are?

Diffusion

Osmosis

Ion Channels

Facilitated Diffusion

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Review

Diffusion the movement of a substancefrom high concentration to lowconcentration

Osmosis the diffusion of water through aselectively permeable membrane

Ion channels help move chargedparticles down their concentration

gradient

Facilitated Diffusion uses transportproteins, called carrier proteins, to movelarge molecules down their concentration

gradient across the cell membrane

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Active Transport

But sometimes charged particles can move UPtheir concentration gradient

Since opposites attract this can happen on its

own But sometimes the cell needs important sugars

and amino acids that have a lowerconcentration outside the cell

If molecules are not charged can they still moveUP their concentration gradient??

YES!!!!

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Active Transport

Active Transport moves moleculesagainst their concentration gradients

Active transport requires the use ofenergy

Cells move substances from a lowconcentration to an area ofhighconcentration

This means that the cell needs more sugars

or amino acids even if there arent manyoutside the cell

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Active Transport

Active transport is usually performed bytransport proteins called pumps

The energy for active transport most oftencomes in the form of ATP

Sodium-Potassium Pump: transports 3sodium ions (Na+) out of the cell and 2potassium ions (K+) in to the cell

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Sodium-PotassiumPump

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Review

So we have now talked about manydifferent types of transport systems thatthe cell uses.

Diffusion

Osmosis

Ion Channels

Facilitated Diffusion

Active Transport

Could there possibly be any more?????

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Movement in Vesicles

YES!! There is one more way!! VESICLES!!

Many substances such as proteins and

polysaccharides (large sugars) are toolarge to be transported by carrier proteins

These substances move across the cellmembrane by the use ofvesicles

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Types of Vesicles

There are two types of vesicles:

Endocytosis

Exocytosis

Endocytosis the movement of asubstance in to the cell

Exocytosis the movement of a substanceout of the cell

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Endocytosis

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Exocytosis