Facilitated Diffusion & active transport

Facilitated Diffusion

• Integral proteins Integral proteins help molecules help molecules through through membrane.membrane.

• 3 characteristics3 characteristics– No energy is usedNo energy is used– SpecificSpecific– May become May become

saturatedsaturated

• Example: glucoseExample: glucoseGlucose molecules entering a cell Glucose molecules entering a cell

using facilitated diffusion.using facilitated diffusion.Hint: “integral” means a part of, integral proteins go through the plasma membrane (also called transmembrane proteins). Perpherial proteins are only on the surface of the membrane.)

Active Transport

• Need to move Need to move molecules up a molecules up a concentration concentration gradient.gradient.

• Uses cellular Uses cellular energyenergy in from of in from of ATP.ATP.

Ions moving across Ions moving across membrane by active membrane by active

transport.transport.

Think: why does the cell need to use energy to pump the yellow balls out? Think about the concentration gradient… is it moving “uphill” or “downhill”?

• Molecule that is Molecule that is needed in the cell needed in the cell is moved through is moved through protein protein with with anotheranother substance.substance.

• Na diffuses back Na diffuses back into cell allowing into cell allowing second molecule second molecule through.through.

Coupled channel.Coupled channel.

Active Transport: Coupled Channels

Hint: Find Na on your periodic table – what is it?

• Hydrogen ions Hydrogen ions (H+) are actively (H+) are actively pumped out of a pumped out of a cellcell

• Diffusion causes Diffusion causes H+ ions to return H+ ions to return through a protein.through a protein.

• When H+ returns When H+ returns ATP is produced.ATP is produced.

• Chemiosmosis Chemiosmosis ((part of part of photosynthesis and photosynthesis and respirationrespiration) )

Chemiosmosis.Chemiosmosis.

Active Transport: Proton Pump

Hint: take another look at your periodic table. What is a hydrogen atom without an electron?

Endocytosis Vs Exocytosis

• Endocytosis:Endocytosis:• Cells form a Cells form a

vesicle to move vesicle to move large solid large solid materials materials intointo the the cell.cell.

• Exocytosis:Exocytosis:• Cells moving Cells moving

large materials large materials out ofout of the cell. the cell.

Hint: when have we used the prefixes ‘endo’ and ‘exo’ before? Look at our Latin roots.

Two types of endocytosisTwo types of endocytosis

• PhagocytosisPhagocytosis– Solid objects moved into the cell. Solid objects moved into the cell.

(“phago” mean to eat.)(“phago” mean to eat.)

• Pinocytosis:Pinocytosis:– Liquids moved into the cell. Liquids moved into the cell.

(“pino” means to (“pino” means to drink)drink)

Summary should be at least 4 sentences.

1. Name 3 features of facilitated diffusion.

2. Name 2 ways active transport is different than passive transport.

3. How do cells get large objects inside?

What does Garfield have wrong about osmosis?