Transport in CellsTransport in Cells

Biology 30 ~ Cells UnitBiology 30 ~ Cells Unit

Mrs. S. Pipke-PainchaudMrs. S. Pipke-Painchaud

Cell MembraneCell Membrane

Cell Membrane Info:Cell Membrane Info:– http://cellbio.utmb.edu/cellbio/membr

ane.htm

Cell MembraneCell Membrane Fluid Mosaic ModelFluid Mosaic Model

Fluid: Fluid: – Phospholipids move at 2 micrometres per Phospholipids move at 2 micrometres per

secondsecond– Proteins move at a much slower rateProteins move at a much slower rate

Mosaic:Mosaic:- Cell membrane is made up of many different - Cell membrane is made up of many different moleculesmolecules- Carrier proteins- Carrier proteins - Phospholipids- Phospholipids

- Glycoproteins- Glycoproteins - Glycolipids- Glycolipids- Cholesterol- Cholesterol

** Animation: ** Animation: http://home.earthlink.net/~shalpine/anim/Life/memb.htm

Fluid MosaicFluid Mosaic– http://www.bio.davidson.edu/people/ma

campbell/111/memb-swf/membranes.swf

– http://www.stolaf.edu/people/giannini/flashanimat/lipids/membrane%20fluidity.swf

Molecules Crossing the Molecules Crossing the MembraneMembrane

Can cross:Can cross:– Hydrocarbons and oxygen because they can Hydrocarbons and oxygen because they can

dissolve in the lipid bilayerdissolve in the lipid bilayer– Small polar moleculesSmall polar molecules

WaterWater Carbon dioxideCarbon dioxide

Cannot Cross:Cannot Cross:– Large polar molecules (Sugar)Large polar molecules (Sugar)– Ions (H+, Na+, Cl-)Ions (H+, Na+, Cl-)

Animation: Animation: http://www.hillstrath.on.ca/moffatt/bio3a/cellbio/celtrans3.htm

Review TopicsReview Topics

Cell Membrane – Fluid MosaicCell Membrane – Fluid Mosaic– http://www.stolaf.edu/people/giannini/fla

shanimat/lipids/membrane%20fluidity.swf

General InfoGeneral Info

Concentration Concentration = [ ] = the number of = [ ] = the number of molecules per volume.molecules per volume.

Brownian Motion:Brownian Motion:– Random movement (and collision of molecules) Random movement (and collision of molecules)

Think back to the collision theory of Science Think back to the collision theory of Science 1010

– Molecules move in all directions with equal Molecules move in all directions with equal frequency and bounce off of each otherfrequency and bounce off of each other

– This causes molecules to spread outThis causes molecules to spread out

Concentration Gradient:Concentration Gradient:– Is a regular concentration change over a Is a regular concentration change over a

distance in a particular direction.distance in a particular direction.

Wikipedia: http://en.wikipedia.org/wiki/Concentration_gradient

Passive TransportPassive Transport

Moving biochemicals and other Moving biochemicals and other particles across membranes without particles across membranes without the use of energy.the use of energy.

DiffusionDiffusion

Is the movement of molecules from Is the movement of molecules from an area of high concentration to an an area of high concentration to an area of low concentration.area of low concentration.

Diffusion is affected by:Diffusion is affected by:– TemperatureTemperature– Pressure (because molecules are forced Pressure (because molecules are forced

to be closer together)to be closer together)– ConcentrationConcentration** Diffusion increases as these variables ** Diffusion increases as these variables

dodo

Example . . . Example . . .

Consider Consider perfume perfume diffusing diffusing around a around a classroom.classroom.

TMSS TMSS example: example: Foods Class Foods Class cooking cooking cinnamon cinnamon bunsbuns

http://www.mun.ca/biology/Osmosis_Diffusion/tutor2.html

ExampleExample

General Anatomy and Physiology – General Anatomy and Physiology – Diffusion DemoDiffusion Demo– http://www.wisc-online.com/objects/index_tj.as

p?objID=AP1903 Interactive Animation:Interactive Animation:

– http://www.wiley.com/legacy/college/boyer/0470003790/animations/membrane_transport/membrane_transport.htm

Diffusion:Diffusion:– http://www.stolaf.edu/people/giannini/flashani

mat/transport/diffusion.swf

Diffusion . . .Diffusion . . . Occurs until everything is equally distributedOccurs until everything is equally distributed

– Equilibrium – a condition in which all acting Equilibrium – a condition in which all acting forces are balanced = stable conditionforces are balanced = stable condition

Example:Example:– As oxygen travels along in the blood until it As oxygen travels along in the blood until it

reaches a cell. In the bloodstream there is a high reaches a cell. In the bloodstream there is a high concentration of oxygen and in the cell there is a concentration of oxygen and in the cell there is a low concentration of oxygen so the molecule of low concentration of oxygen so the molecule of oxygen diffuses from an area of high oxygen diffuses from an area of high concentration to an area of low concentration.concentration to an area of low concentration.

– Carbon dioxide does the reverse and catches a Carbon dioxide does the reverse and catches a ride back to the lung to be exhaled.ride back to the lung to be exhaled.

DemosDemos

Hot water and Cold water and red Hot water and Cold water and red dye.dye.

Facilitated DiffusionFacilitated Diffusion

Passive TransportPassive Transport Molecules diffuse across the cell Molecules diffuse across the cell

membrane with the help of carrier membrane with the help of carrier proteins.proteins.– Protein carrier molecule speeds up the Protein carrier molecule speeds up the

diffusion process of substances already moving diffusion process of substances already moving across the membrane.across the membrane.

– Ex// sugars (polar molecules) and ionsEx// sugars (polar molecules) and ions– Movement is always down the concentration Movement is always down the concentration

gradientgradient

Facilitated Diffusion AnimationFacilitated Diffusion Animation– http://www.d.umn.edu/~sdowning/Mem

branes/diffusionanimation.html Animation:Animation:

– http://bio.winona.edu/berg/ANIMTNS/facdiff.htm

OsmosisOsmosis

The movement of water molecules from an The movement of water molecules from an area of high concentration to an area of area of high concentration to an area of low concentration low concentration

Occurs through a selectively permeable Occurs through a selectively permeable membrane.membrane.

Water moves through the membrane to Water moves through the membrane to balance the concentrationbalance the concentration– Water follows the concentration gradient.Water follows the concentration gradient.

Process continues until the system is Process continues until the system is equal.equal.

OsmosisOsmosis Osmosis DemoOsmosis Demo

– http://www.stolaf.edu/people/giannini/flashanimat/transport/osmosis.swf

General Passive Transport InfoGeneral Passive Transport Info– http://www.biologycorner.com/bio1/diffusion.html#

Introduces Hyper/hypo/isotonic solutionsIntroduces Hyper/hypo/isotonic solutions– http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/Os

mosis.htm Osmosis:Osmosis:

– http://www.colorado.edu/eeb/web_resources/osmosis/ Osmosis:Osmosis:

– http://ull.chemistry.uakron.edu/genobc/animations/osmosis.mov

Osmosis DemosOsmosis Demos

Plastic bag and Iodine demoPlastic bag and Iodine demo Egg and vinegar and syrupEgg and vinegar and syrup

Active TransportActive Transport

The transport of biochemicals and The transport of biochemicals and other particles across a membrane.other particles across a membrane.

This process requires energy.This process requires energy.

Animation Animation – http://www.brookscole.com/chemistry_d/

templates/student_resources/shared_resources/animations/ion_pump/ionpump.html

Active Transport + Carrier Active Transport + Carrier ProteinsProteins

A molecule finds a specific A molecule finds a specific carrier/transport proteincarrier/transport protein

The transport protein opensThe transport protein opens Molecule moves insideMolecule moves inside Transport protein opens to the insideTransport protein opens to the inside Molecule moves into the cell.Molecule moves into the cell. ** the molecule is moving against the ** the molecule is moving against the

concentration gradient so energy is concentration gradient so energy is required.required.

Active TransportActive Transport

http://www.biologycorner.com/bio1/active.html

Active Transport (Carrier Proteins)Active Transport (Carrier Proteins)– http://www.northland.cc.mn.us/biology/B

iology1111/animations/active1.swf Reviews both passive and active Reviews both passive and active

transport.transport.– http://www.northland.cc.mn.us/biology/B

iology1111/animations/active1.swf

EndocytosisEndocytosis

Cells engulf large particles by Cells engulf large particles by extending cytoplasm around the extending cytoplasm around the particleparticle

As the membranes come together – As the membranes come together – ingested particles are trapped in a ingested particles are trapped in a pouch (vesicle/ vacuole)pouch (vesicle/ vacuole)

Enzymes from the lysosomes are Enzymes from the lysosomes are then used to digest large molecules.then used to digest large molecules.

Endocytosis WebsitesEndocytosis Websites

Max Animations:Max Animations:– http://www.maxanim.com/physiology/En

docytosis%20and%20Exocytosis/Endocytosis%20and%20Exocytosis.htm

http://www.sumanasinc.com/webcontent/anisamples/molecularbiology/endocytosis.html

PhagocytosisPhagocytosis

Cells engulf solid particlesCells engulf solid particles– Ex// white blood cells engulf bacteriaEx// white blood cells engulf bacteria

PhagocytosisPhagocytosis– http://student.ccbcmd.edu/~gkaiser/biot

utorials/eustruct/phagocyt.html

PinocytosisPinocytosis

Cells engulf liquid droplets Cells engulf liquid droplets – Ex// fats in the small intestineEx// fats in the small intestine

PinocytosisPinocytosis– http://student.ccbcmd.edu/~gkaiser/biotutorial

s/eustruct/pinocyt.html Diagram of bothDiagram of both

– http://www.coolschool.ca/lor/BI12/unit4/U04L05.htm

ExocytosisExocytosis

Process by which large molecules held Process by which large molecules held within the cell are transported to the within the cell are transported to the external environmentexternal environment

Ex// release of waste productsEx// release of waste products Small vesicles break off from the golgi Small vesicles break off from the golgi

apparatus and move to the cell apparatus and move to the cell membranemembrane

Here they fuse with the cell Here they fuse with the cell membrane and are releasedmembrane and are released

ExocytosisExocytosis

Exocytosis:Exocytosis:– http://academic.brooklyn.cuny.edu/biolo

gy/bio4fv/page/exocy.htm Exocytosis:Exocytosis:

– http://www.stanford.edu/group/Urchin/GIFS/exocyt.gif

Endo/Exo Review Endo/Exo Review – http://www.stolaf.edu/people/giannini/fla

shanimat/cellstructures/phagocitosis.swf

ReviewReview Access Access Excellence: Excellence: http://www.accessexcellence.org/RC/VL/GG/ecb/comparison_active_passive_transport.html

Info from: Access Excellence Info from: Access Excellence – http://www.accessexcellence.org/RC/VL/GG/ecb/http://www.accessexcellence.org/RC/VL/GG/ecb/

comparison_active_passive_transport.htmlcomparison_active_passive_transport.html

Solutes cross cell membranes by passive or active Solutes cross cell membranes by passive or active transporttransport. If uncharged solutes are small enough, they can . If uncharged solutes are small enough, they can move down their concentration gradients directly across move down their concentration gradients directly across the lipid bilayer itself by simple diffusion. Examples of such the lipid bilayer itself by simple diffusion. Examples of such solutes are ethanol, carbon dioxide, and oxygen. Most solutes are ethanol, carbon dioxide, and oxygen. Most solutes, however, can cross the membrane only if there is a solutes, however, can cross the membrane only if there is a membrane transport protein (a carrier protein or a channel membrane transport protein (a carrier protein or a channel protein) to transfer them. As indicated, passive transport, in protein) to transfer them. As indicated, passive transport, in the same direction as a concentration gradient, occurs the same direction as a concentration gradient, occurs spontaneously, whereas transport against a concentration spontaneously, whereas transport against a concentration gradient (active transport) requires an input of energy. Only gradient (active transport) requires an input of energy. Only carrier proteins can carry out active transport, but both carrier proteins can carry out active transport, but both carrier proteins and channel proteins can carry out passive carrier proteins and channel proteins can carry out passive transport. transport.

ResourcesResources Chart of Movement across the membrane:Chart of Movement across the membrane:

– http://defiant.corban.edu/jjohnson/Pages/BioI/07/http://defiant.corban.edu/jjohnson/Pages/BioI/07/Traffic_ConceptMap.htmlTraffic_ConceptMap.html

Listing of Bio InfoListing of Bio Info– http://science.nhmccd.edu/biol/bio1int.htm#biochemhttp://science.nhmccd.edu/biol/bio1int.htm#biochem

http://www.northland.cc.mn.us/biology/http://www.northland.cc.mn.us/biology/Biology1111/animations/active1.swfBiology1111/animations/active1.swf

http://www.stolaf.edu/people/giannini/biologicalhttp://www.stolaf.edu/people/giannini/biological%20anamations.html%20anamations.html

http://defiant.corban.edu/jjohnson/Pages/BioI/http://defiant.corban.edu/jjohnson/Pages/BioI/07/Membrane.html07/Membrane.html