Cell Membrane 100 Online

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Plasma Membrane

Structure andFunction

Chapter 4


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Outline

Phospholipid Bilayer Fluid Mosaic Model

Membrane Proteins

Diffusion

Facilitated Diffusion

Osmosis Bulk Transport

Active Transport


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Membrane Functions

Protection

Communication

Selectively allow substances in Respond to environment

Recognition


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Plasma Membrane

Boundary that separates the living cellfrom

its non-livingsurroundings.

Phospholipid bilayer

Amphipathic- having both:

hydrophilic heads

hydrophobic tails

~8 nm thick Is a dynamic structure

Phospholipid
http://www.d.umn.edu/~sdowning/Membranes/phospholipidlateralmovanim.htmlhttp://www.d.umn.edu/~sdowning/Membranes/phospholipidlateralmovanim.html


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Fluid-Mosaic Model
http://www.youtube.com/watch?v=Qqsf_UJcfBc&mode=user&search=http://telstar.ote.cmu.edu/biology/animation/Membranes/membranes.htmlhttp://www.youtube.com/watch?v=Qqsf_UJcfBc&mode=user&search=http://www.youtube.com/watch?v=Qqsf_UJcfBc&mode=user&search=http://www.youtube.com/watch?v=Qqsf_UJcfBc&mode=user&search=


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ProteinsFor Function

Transport

Receptors

Enzymes

Signal Transducers

Support


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PROTEINS CAN

MOVE IN THEMEMBRANE,

TOO!

Plasma Membrane Proteins
http://www.d.umn.edu/~sdowning/Membranes/proteinmobilityanim.htmlhttp://www.d.umn.edu/~sdowning/Membranes/proteinmobilityanim.htmlhttp://www.d.umn.edu/~sdowning/Membranes/proteinmobilityanim.htmlhttp://www.d.umn.edu/~sdowning/Membranes/proteinmobilityanim.htmlhttp://www.d.umn.edu/~sdowning/Membranes/proteinmobilityanim.htmlhttp://www.d.umn.edu/~sdowning/Membranes/proteinmobilityanim.htmlhttp://www.d.umn.edu/~sdowning/Membranes/proteinmobilityanim.htmlhttp://www.d.umn.edu/~sdowning/Membranes/proteinmobilityanim.html


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Channel protein


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Carrier protein


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Cell recognition protein


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Receptor protein


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Enzymatic protein

Example ofEnzymatic

activityassociatedwith a

membrane:G-proteincascade

G-PROTEINANIMATION 2

G-proteinanimation 3
http://www.sp.uconn.edu/~bi107vc/images/anim/SigtranRA.gifhttp://entochem.tamu.edu/G-Protein/index.htmlhttp://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/signals.htmhttp://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/signals.htmhttp://www.sp.uconn.edu/~bi107vc/images/anim/SigtranRA.gifhttp://entochem.tamu.edu/G-Protein/index.htmlhttp://entochem.tamu.edu/G-Protein/index.htmlhttp://www.sp.uconn.edu/~bi107vc/images/anim/SigtranRA.gifhttp://www.sp.uconn.edu/~bi107vc/images/anim/SigtranRA.gifhttp://www.sp.uconn.edu/~bi107vc/images/anim/SigtranRA.gifhttp://entochem.tamu.edu/G-Protein/index.htmlhttp://www.sp.uconn.edu/~bi107vc/images/anim/SigtranRA.gifhttp://www.sp.uconn.edu/~bi107vc/images/anim/SigtranRA.gifhttp://www.sp.uconn.edu/~bi107vc/images/anim/SigtranRA.gifhttp://www.sp.uconn.edu/~bi107vc/images/anim/SigtranRA.gifhttp://entochem.tamu.edu/G-Protein/index.htmlhttp://entochem.tamu.edu/G-Protein/index.htmlhttp://entochem.tamu.edu/G-Protein/index.htmlhttp://entochem.tamu.edu/G-Protein/index.htmlhttp://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/signals.htmhttp://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/signals.htmhttp://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/signals.htmhttp://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb1/part2/signals.htm


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Permeability of the Cell Membrane-

Differentially Permeable


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Permeability of the Cell Membrane


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Diffusion

the passivemovement of molecules from

a higher to a lower concentration untilequilibriumis reached.

How can we explain diffusion?

Gases move through plasma membranesby diffusion.

OsmosisA special case of diffusion

DIFFUSION


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Process of diffusion


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Gas exchange in lungs by diffusion


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Osmosis

The diffusion of water across a

differentially permeable

membrane due toconcentration differences


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TONICITY

Refers to the concentration of

SOLUTES

Is aRELATIVE term, comparing twodifferent solutions

Hypertonic

Hypotonic

Isotonic


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Hypertonic

A solutionwith a greater solute

concentrationcompared to another solution.

3% NaCl

97% H2O

Red Blood Cell

5% NaCl

95% H2O

solution

Whichwaywill

thewatermove?


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Hypotonic

A solutionwith a lower solute concentration

compared to another solution.

3% Na

97% H2O

Red Blood Cell

1% Na

99% H2O

solution

Whichwaywill

thewatermove?


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ISOTONIC SOLUTION


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HYPOTONIC SOLUTION


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HYPERTONIC SOLUTION


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FunctionTransport. Are specific,

combine with only a certain type of

molecule. Types

Facilitated transport--passive

Active transportrequires energy

Carrier Proteins


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Facilitated Transport
http://www.d.umn.edu/~sdowning/Membranes/diffusionanimation.htmlhttp://www.wiley.com/legacy/college/boyer/0470003790/animations/membrane_transport/membrane_transport.htmhttp://www.d.umn.edu/~sdowning/Membranes/diffusionanimation.html


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Active Transport
http://www.wiley.com/legacy/college/boyer/0470003790/animations/membrane_transport/membrane_transport.htmhttp://www.wiley.com/legacy/college/boyer/0470003790/animations/membrane_transport/membrane_transport.htm


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The sodium-potassium pump

E t i d
http://www.wiley.com/legacy/college/boyer/0470003790/animations/membrane_transport/membrane_transport.htm


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Exocytosis---Cellular secretion

Endocytosis

PhagocytosisCell eating

PinocytosisCell drinking

Receptor-mediated

endocytosis-specific particles,

recognition.

Exocytosis and

Endocytosis


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Exocytosis
http://www.mhhe.com/biosci/esp/2001_gbio/folder_structure/ce/m3/s6/assets/real/cem3s6_1.rm


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Phagocytosis

Phagocytosis 1

Phagocytosis 2
http://www.cat.cc.md.us/~gkaiser/biotutorials/eustruct/phagocyt.htmlhttp://www.cat.cc.md.us/courses/bio141/lecguide/unit2/innate/images/phagocytosis.movhttp://micro.magnet.fsu.edu/moviegallery/pondscum/protozoa/amoeba/t1/amoeba05.htmlhttp://micro.magnet.fsu.edu/moviegallery/pondscum/protozoa/amoeba/t1/amoeba05.htmlhttp://www.cat.cc.md.us/courses/bio141/lecguide/unit2/innate/images/phagocytosis.movhttp://www.cat.cc.md.us/~gkaiser/biotutorials/eustruct/phagocyt.html


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Pinocytosis

Receptor mediated
http://www.cat.cc.md.us/~gkaiser/biotutorials/eustruct/pinocyt.html


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Receptor-mediated

Endocytosis
http://bcs.whfreeman.com/thelifewire/content/chp05/0502003.html


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SUMMARY

Phospholipid Bilayer Fluid Mosaic Model

Membrane Proteins

Diffusion

Facilitated Diffusion

Osmosis Bulk Transport

Active Transport

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Cell Membrane 100 Online