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Transport in Cells

Transport in Cells. Biology 30 ~ Cells Unit Mrs. S. Pipke-Painchaud. Cell Membrane. Cell Membrane Info: http://cellbio.utmb.edu/cellbio/membrane.htm. Cell Membrane. Fluid Mosaic Model Fluid: Phospholipids move at 2 micrometres per second Proteins move at a much slower rate Mosaic:

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Transport in Cells

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  1. Transport in Cells Biology 30 ~ Cells Unit Mrs. S. Pipke-Painchaud

  2. Cell Membrane • Cell Membrane Info: • http://cellbio.utmb.edu/cellbio/membrane.htm

  3. Cell Membrane • Fluid Mosaic Model Fluid: • Phospholipids move at 2 micrometres per second • Proteins move at a much slower rate Mosaic: - Cell membrane is made up of many different molecules - Carrier proteins - Phospholipids - Glycoproteins - Glycolipids - Cholesterol ** Animation: http://home.earthlink.net/~shalpine/anim/Life/memb.htm

  4. Fluid Mosaic • http://www.bio.davidson.edu/people/macampbell/111/memb-swf/membranes.swf • http://www.stolaf.edu/people/giannini/flashanimat/lipids/membrane%20fluidity.swf

  5. Molecules Crossing the Membrane • Can cross: • Hydrocarbons and oxygen because they can dissolve in the lipid bilayer • Small polar molecules • Water • Carbon dioxide • Cannot Cross: • Large polar molecules (Sugar) • Ions (H+, Na+, Cl-) • Animation: http://www.hillstrath.on.ca/moffatt/bio3a/cellbio/celtrans3.htm

  6. Review Topics • Cell Membrane – Fluid Mosaic • http://www.stolaf.edu/people/giannini/flashanimat/lipids/membrane%20fluidity.swf

  7. General Info • Concentration = [ ] = the number of molecules per volume. • Brownian Motion: • Random movement (and collision of molecules)  Think back to the collision theory of Science 10 • Molecules move in all directions with equal frequency and bounce off of each other • This causes molecules to spread out

  8. Concentration Gradient: • Is a regular concentration change over a distance in a particular direction. Wikipedia: http://en.wikipedia.org/wiki/Concentration_gradient

  9. Passive Transport • Moving biochemicals and other particles across membranes without the use of energy.

  10. Diffusion • Is the movement of molecules from an area of high concentration to an area of low concentration. • Diffusion is affected by: • Temperature • Pressure (because molecules are forced to be closer together) • Concentration ** Diffusion increases as these variables do

  11. Example . . . • Consider perfume diffusing around a classroom. • TMSS example: Foods Class cooking cinnamon buns http://www.mun.ca/biology/Osmosis_Diffusion/tutor2.html

  12. Example • General Anatomy and Physiology – Diffusion Demo • http://www.wisc-online.com/objects/index_tj.asp?objID=AP1903 • Interactive Animation: • http://www.wiley.com/legacy/college/boyer/0470003790/animations/membrane_transport/membrane_transport.htm • Diffusion: • http://www.stolaf.edu/people/giannini/flashanimat/transport/diffusion.swf

  13. Diffusion . . . • Occurs until everything is equally distributed • Equilibrium – a condition in which all acting forces are balanced = stable condition • Example: • As oxygen travels along in the blood until it reaches a cell. In the bloodstream there is a high concentration of oxygen and in the cell there is a low concentration of oxygen so the molecule of oxygen diffuses from an area of high concentration to an area of low concentration. • Carbon dioxide does the reverse and catches a ride back to the lung to be exhaled.

  14. Demos • Hot water and Cold water and red dye.

  15. Facilitated Diffusion • Passive Transport • Molecules diffuse across the cell membrane with the help of carrier proteins. • Protein carrier molecule speeds up the diffusion process of substances already moving across the membrane. • Ex// sugars (polar molecules) and ions • Movement is always down the concentration gradient

  16. Facilitated Diffusion Animation • http://www.d.umn.edu/~sdowning/Membranes/diffusionanimation.html • Animation: • http://bio.winona.edu/berg/ANIMTNS/facdiff.htm

  17. Osmosis • The movement of water molecules from an area of high concentration to an area of low concentration • Occurs through a selectively permeable membrane. • Water moves through the membrane to balance the concentration • Water follows the concentration gradient. • Process continues until the system is equal.

  18. Osmosis • Osmosis Demo • http://www.stolaf.edu/people/giannini/flashanimat/transport/osmosis.swf • General Passive Transport Info • http://www.biologycorner.com/bio1/diffusion.html# • Introduces Hyper/hypo/isotonic solutions • http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/Osmosis.htm • Osmosis: • http://www.colorado.edu/eeb/web_resources/osmosis/ • Osmosis: • http://ull.chemistry.uakron.edu/genobc/animations/osmosis.mov

  19. Osmosis Demos • Plastic bag and Iodine demo • Egg and vinegar and syrup

  20. Active Transport • The transport of biochemicals and other particles across a membrane. • This process requires energy. • Animation • http://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/ion_pump/ionpump.html

  21. Active Transport + Carrier Proteins • A molecule finds a specific carrier/transport protein • The transport protein opens • Molecule moves inside • Transport protein opens to the inside • Molecule moves into the cell. • ** the molecule is moving against the concentration gradient so energy is required.

  22. Active Transport • http://www.biologycorner.com/bio1/active.html • Active Transport (Carrier Proteins) • http://www.northland.cc.mn.us/biology/Biology1111/animations/active1.swf • Reviews both passive and active transport. • http://www.northland.cc.mn.us/biology/Biology1111/animations/active1.swf

  23. Endocytosis • Cells engulf large particles by extending cytoplasm around the particle • As the membranes come together – ingested particles are trapped in a pouch (vesicle/ vacuole) • Enzymes from the lysosomes are then used to digest large molecules.

  24. Endocytosis Websites • Max Animations: • http://www.maxanim.com/physiology/Endocytosis%20and%20Exocytosis/Endocytosis%20and%20Exocytosis.htm • http://www.sumanasinc.com/webcontent/anisamples/molecularbiology/endocytosis.html

  25. Phagocytosis • Cells engulf solid particles • Ex// white blood cells engulf bacteria • Phagocytosis • http://student.ccbcmd.edu/~gkaiser/biotutorials/eustruct/phagocyt.html

  26. Pinocytosis • Cells engulf liquid droplets • Ex// fats in the small intestine • Pinocytosis • http://student.ccbcmd.edu/~gkaiser/biotutorials/eustruct/pinocyt.html • Diagram of both • http://www.coolschool.ca/lor/BI12/unit4/U04L05.htm

  27. Exocytosis • Process by which large molecules held within the cell are transported to the external environment • Ex// release of waste products • Small vesicles break off from the golgi apparatus and move to the cell membrane • Here they fuse with the cell membrane and are released

  28. Exocytosis • Exocytosis: • http://academic.brooklyn.cuny.edu/biology/bio4fv/page/exocy.htm • Exocytosis: • http://www.stanford.edu/group/Urchin/GIFS/exocyt.gif • Endo/Exo Review • http://www.stolaf.edu/people/giannini/flashanimat/cellstructures/phagocitosis.swf

  29. Review • Access Excellence: http://www.accessexcellence.org/RC/VL/GG/ecb/comparison_active_passive_transport.html

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

  31. Resources • Chart of Movement across the membrane: • http://defiant.corban.edu/jjohnson/Pages/BioI/07/Traffic_ConceptMap.html • Listing of Bio Info • http://science.nhmccd.edu/biol/bio1int.htm#biochem • http://www.northland.cc.mn.us/biology/Biology1111/animations/active1.swf • http://www.stolaf.edu/people/giannini/biological%20anamations.html • http://defiant.corban.edu/jjohnson/Pages/BioI/07/Membrane.html

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