1 / 92

PLASMA MEMBRANES

PLASMA MEMBRANES. EVERY CELL HAS A CELL MEMBRANE. FUNCTIONS OF THE PLASMA MEMBRANE. REGULATES THE PASSAGE OF MATERIALS INTO AND OUT OF THE CELL RECEIVES INFORMATION FROM THE ENVIRONMENT MAINTAINS THE STRUCTURAL AND CHEMICAL RELATIONSHIPS OF THE CELL WITH ITS NEIGHBORS CELL PROTECTION

reginald-ethelbert
Download Presentation

PLASMA MEMBRANES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PLASMA MEMBRANES EVERY CELL HAS A CELL MEMBRANE

  2. FUNCTIONS OF THE PLASMA MEMBRANE • REGULATES THE PASSAGE OF MATERIALS INTO AND OUT OF THE CELL • RECEIVES INFORMATION FROM THE ENVIRONMENT • MAINTAINS THE STRUCTURAL AND CHEMICAL RELATIONSHIPS OF THE CELL WITH ITS NEIGHBORS • CELL PROTECTION • SECRETION • CELLULAR MOVEMENT • IMPULSE TRANSMISSION

  3. REGULATES THE PASSAGE OF MATERIALS INTO AND OUT OF CELL • SELECTIVELY PERMEABLE • MAINTAINS A CONSTANT INTERNAL CONDITION DESPITE CHANGES IN EXTERNAL ENVIRONMENT

  4. RECEIVES INFORMATION FROM THE ENVIRONMENT • RECEPTOR PROTEINS RECEIVE CHEMICAL MESSAGES • MEMBRANE IS STIMULATED TO SEND MESSAGE INTO CELL • CAUSES SOME TYPE OF RESPONSE

  5. MAINTAINS THE STRUCTURAL AND CHEMICAL RELATIONSHIPS OF THE CELL WITH ITS NEIGHBORS • RECOGNITION • ADHERANCE • EXCHANGE OF MATERIALS • RESPOND TO FIRST MESSENGERS

  6. OTHER FUNCTIONS • CELL PROTECTION • SECRETION • CELLULAR MOVEMENT • IMPULSE TRANSMISSION

  7. THE FLUID MOSAIC MODEL OF THE PLASMA MEMBRANE • 6-10 NANOMETERS THICK • FLUID LIPID BILAYER • PROTEINS EMBEDDED • EACH LAYER IS CALLED LEAFLET

  8. THE LIPID COMPONENTS OF THE PLASMA MEMBRANE • PHOSPHOLIPIDS • HYDROPHILIC • HYDROPHOBIC • GLYCOLIPIDS • CHOLESTEROL

  9. PHOSPHOLIPIDS • MAIN COMPONENT OF MEMBRANES • PHOSPHATE AND GYLCEROL HEAD • FATTY ACID TAILS • VARY IN SATURATION

  10. CHOLESTEROL • STEROID • FOUND BETWEEN PHOSPHOLIPIDS • AFFECTS MEMBRANE FLUIDITY

  11. THERMOPHILES • HIGH TEMPERATURES • MAKES MEMBRANE LESS FLUID • RESTRAINS MOVEMENT OF PHOSPHOLIPIDS

  12. PSYCHROPHILES • LOW TEMPERATURES • HINDERS PACKING OF PHOSPHOLIIDS • LOWERS TEMPERATURE FOR SOLIDIFICATION

  13. GLYCOLIPIDS

  14. LIPID BILAYER IS VERY IMPERMEABLE TO IONS AND POLAR MOLECULES • SERVE AS BARRIER TO IONS AND POLAR MOLECULES • WATER IS AN EXCEPTION • MOVES EASILY THROUGH MEMBRANE

  15. PROTEINS IN THE CELL MEMBRANE

  16. TRANSPORT ENZYMATIC ACTIVITY SIGNAL TRANSDUCTION CELL TO CELL RECOGNITION INTERCELLULAR JOINING ATTACHMENT TO CYTOSKELETON AND EXTRACELLULAR MATRIX SPECIFIC FUNCTIONS OF MEMBRANE PROTEINS

  17. TRANSPORT • http://www.miracosta.cc.ca.us/home/sfoster/neurons/membraneimt1.gif

  18. CELLULAR RECOGNITION

  19. INTERCELLULAR JOINING

  20. ATTACHMENT TO THE CYTOSKELETON AND EXTRACELLULAR MATRIX

  21. PROTEINS IN THE CELL MEMBRANE • HYDROPHOBIC • HYDOPHILIC • INTEGRAL PROTEINS • PERIPHERAL PROTEINS

  22. PERIPHERAL PROTEIN

  23. INTEGRAL PROTEIN

  24. GLYCOPROTEINS • PROTEIN WITH ADDITION OF A CARBOHYDRATE • MOST OF PROTEINS ASSOCIATED WITH INNER SIDE OF MEMBRANE ARE GLYCOLIPIDS • SERVE AS COMMUNICATION SYSTEM WITH ENVIRONMENT • SOME ARE PERPIPHERAL PROTEINS • MAY FORM GLYCOCALYX

  25. THE CELL MEMBRANE AND THE CYTOSKELETON • CYTOSKELETON GIVES SHAPE • COMPLEX INNER SCAFFOLDING

  26. MICROVILLI • MANY CELLS HAVE FREE SURFACES • TINY EVAGINATIONS OF MEMBRANE • INCREASE SURFACE AREA OF CELL

  27. BRUSH BORDER

  28. MOVEMENT OF MATERIALS INTO OR OUT OF THE CELL • DEPENDS ON THE STRUCTURE OF THE MEMBRANE • DEPENDS ON THE SIZE AND CHARGE OF THE MOLECULES

  29. PERMEABLE VS IMPERMEABLE

  30. SELECTIVELY PERMEABLE • ALLOWS SOME TO PASS THROUGH • BLOCKS OTHERS

  31. MECHANISMS OF MOVEMENT • PASSIVE VS ACTIVE

  32. PASSIVE MOVEMENT • DIFFUSION • SIMPLE DIFFUSION • THROUGH LIPID BILAYER • OR CHANNEL PROTEINS • FACILITATED DIFFUSION • USES CARRIER MOLECULES • OSMOSIS • SPECIAL TYPE • WATER ONLY

  33. SIMPLE DIFFUSION • MOVE DUE TO RANDOM KINETIC ENERGY OF MOLECULES THEMSELVES • THE CELL DOES NOT EXPEND ENERGY

  34. SIMPLE DIFFUSION • THE MOVEMENT OF PARTICLES FROM A REGION OF HIGHER CONCENTRATION TO A REGION OF LOWER CONCENTRATION DOWN A CONCENTRATION GRADIENT • INEFFICIENT PROCESS • USED BY EUKARYOTES MORE THAN PROKARYOTES

  35. RATE OF DIFFUSION • DEPENDS ON • SIZE OF ATOMS OR MOLECULES • TEMPERATURE • STATE OF MATTER • SOLID • LIQUID • GAS

  36. IMPORTANCE OF DIFFUSION • OXYGEN, CARBON DIOXIDE, WATER, OTHER SMALL MOLECULES CAN DIFFUSE INTO AND OUT OF CELLS EASILY • MATERIAL MOVE THROUGHOUT THE INTERIOR OF THE CELL BY DIFFUSION

  37. FACILTIATED DIFFUSION • DIFFUSION THROUGH SPECIAL CHANNELS • ALLOWS HYDROPHILIC OR CHARGED MOLECULES TO PASS THROUGH MEMBRANE

  38. IMPORTANCE OF CARRIER PROTEINS • ALSO CALLED TRANSPORT PROTEINS OR PERMEASES • SPECIALIZED TRANSPORT PROTEINS • ASSIST THE MOVEMENT OF MOLECULES THORUGH MEMBRANE • MOLECULES MOVE DOWN CONCENTRATION GRADIENT

  39. CARRIER PROTEINS • EXTEND THROUGH MEMBRANE FROM EXTERIOR TO INTERIOR OF CELL • PROVIDE A WATER FILLED CHANNEL • RECEPTOR SITES SPECIFIC BIND TO ONE KIND OF MOLECULE • CARRIER PROTEIN CHANGES SHAPE • MOLECULE IS CARRIED INTO CELL

  40. TRANSPORT PROTEINS • CHANNEL PROTEINS • AQUAPORINS • GATED CHANNELS • LIGAND GATED • ALSO CALLED CHEMICALLY GATED • ELECTRICALLY GATED

  41. DIFFUSION IS A PASSIVE PROCESS • DOWN CONCENTRATION GRADIENT • DEPENDS ON RANDOM KINETIC ENERGY OF MOLECULE ITSELF

  42. FACILITATED DIFFUSION

  43. FACILITATED DIFFUSION IS SELECTIVE • CARRIER PROTEINS ONLY ACCEPTS CERTAIN TYPES OF MOLECULES

  44. UNIPORTER

  45. OSMOSIS • A SPECIAL TYPE OF DIFFUSION • IT IS THE DIFFUSION OF WATER MOLECULES FROM A REGION OF HIGH WATER CONCENTRATION TO AN AREA OF LOWWATER CONCENTRATION ACROSS A SEMIPERMEABLE MEMBRANE

  46. PLASMA MEMBRANES SELECTIVELY REGULATE THE MOVEMENT OF MOST SOLUTES • WATER CAN MOVE FREELY THROUGH MEMBRANE

  47. OSMOREGULATION IN ANIMALS

  48. OSMOREGULATION IN PLANT CELLS

  49. ISOTONIC SOLUTION • WHEN LIVING CELLS ARE PLACED IN A SOLUTION THAT HAS A SOLUTE CONCENTRATION EQUAL TO THAT IN THE CELLS, THE WATER MOLECULE CONCENTRATION IS ALSO EQUAL INSIDE AND OUTSIDE THE CELL • WATER MOLECULES WILL MOVE INTO AND OUT OF THE CELL AT THE SAME RATE

  50. CELL IN AN ISOTONIC ENVIRONMENT • http://jcs.biologists.org/cgi/reprint/113/8/1365.pdf

More Related