December 7, 2015

1. December 7, 2015 Reminder: Ch 6 and Microscope Quiz Tmrw Microscope Lab Due Today Chapter 7 Checklist Due Today WarmUp: Socrative – Chapter 6 Cells Review Questions Socrative.com APSBARRO

2. Transport Interactive

3. Plasma Membrane Structure and Function Image from: http://www.biologie.uni-hamburg.de/b-online/ge22/03.gif Chapter 7

4. FLUID MOSAIC MODEL Click here to See Fluidity Amphipathic Ratio of saturated and unsaturated fats Selectively permeable Barrier

5. Phospholipids:PHOBIC TAILS in center determine what can pass through

6. HYDROPHILIC/HYDROPHOBIC areas determine positions of molecules in cell membranes hydrophobic amino acids • stick in the lipid membrane • anchors the protein in membrane hydrophilic amino acids • stick out in the watery fluid in or out of cell

7. Membrane Proteins • Proteins determine most of membrane’s specific functions • cell membrane & organelle membranes each have unique collections of proteins • Membrane proteins: • peripheral proteins = loosely bound to surface of membrane • integral proteins = penetrate into lipid bilayer, often completely spanning the membrane = transmembrane protein

8. Membrane Carbohydrates • Attached to proteins (glycoproteins) or lipids (glycolipids) • Play a key role in cell-cell recognition • Example: CD4 • Example: Blood Type http://faculty.southwest.tn.edu/rburkett/GB1-osmosis.htm

9. Membranes provide a variety of cell functions

10. What is the role of cholesterol in the cell membrane?

11. Molecules need to move across membranes in cells OUT waste ammonia salts CO2 H2O products IN food carbohydrates sugars, proteins amino acids lipids salts, O2, H2O Image modiified from: http://www.accessexcellence.org/AB/GG/importProt.html

12. What are examples of passive transport?

13. inside cell outside cell Small non-polar molecules (O2 & CO2) and hydrophobic molecules (fats & other lipids) can slip directly through the phospholipid cell membrane, but… What molecules can get through directly? lipid O2 Gasses salt NH3 sugar aa H2O What about other stuff?

14. Diffusion • 2nd Law of Thermodynamicsgoverns biological systems • Universe tends towards disorder Animatioin from: http://www.biologycorner.com/resources/diffusion-animated.gif • Diffusion • movement from [higher][lower] concentration

15. Diffusion will also happen across a cell membrane as long as there is a difference in concentration and the membrane will let the molecule pass through.

16. Example: DIFFUSION IN CELLS http://facstaff.bloomu.edu/gdavis/links%20100.htm O2 automatically moves from HIGHER concentration (in lungs) to LOWER concentration (in blood) CO2 automatically moves from HIGHER concentration (in blood) to LOWER concentration (in lungs) http://www.le.ac.uk/pa/teach/va/anatomy/case2/2_2.html

17. Diffusion of 2 Solutes • Each substance diffuses down its own concentration gradient, independent of concentration gradients of other substances What happens at equilibrium?

18. Facilitated diffusion Move from HIGH to LOW concentration with aid of membrane transport proteins • passive transport • no energy needed • facilitated = with help.. Too big to fit through • Type of transport protein called (carrier protein)

19. Facilitated Diffusion Animation from: http://bio.winona.edu/berg/ANIMTNS/facdifan.gif Carrier Proteins Grab molecule, undergo conformational change, flip to other side Ex: Facilitated Diffusion Channel Proteins Create passageway forsubstances to pass through Example: Osmosis May be gated or not:open in response to chemical or electrical signals Animation from: http://www2.uic.edu/~myilma1/ionchannel.gif

20. The Special Case of WaterMovement of water across the cell membrane = OSMOSIS

21. Osmosis is diffusion of water • Water is very important, so we talk about water separately • Diffusion of water from high concentration of water to low concentration of water • across a semi-permeable membrane • Passive • Uses no energy • Channel protein

22. Aquaporins 1991 | 2003 • Transport proteins that move water rapidly into & out of cells (3 billion/second) • evidence that there were water channels Peter Agre John Hopkins Roderick MacKinnon Rockefeller

23. What body organ would have a high number of aquaporins to reclaim water needed for excretion of liquid waste?

25. What if cell needs to move a molecule _________ the CONCENTRATION GRADIENT?_______________ AGAINST Cell example: Want to put MORE glucose into mitochondria when there is already glucose in there (LOWER HIGHER) Image from: http://www.biologyclass.net/mitochondria.jpg

26. What if a cell needs to move _____ or ______ moleculesthat can’t getthrough themembrane? LARGE POLAR http://www.d.umn.edu/~sdowning/Membranes/membraneImages/jpegimages/diffusionmedium.jpg

27. What if cell needs to move molecules really _______? (can’t wait for it to diffuse) FAST Cell example: Movement of Na + & K+ ions required to send nerve signals http://www.steve.gb.com/images/science/neuron.png

28. Cells need a ____ to ____ molecules across cell membranes that _______ across by ___________ WAY HELP can’t go themselves

29. Kidspiration by: Riedell

30. Gated channels • Open only in presence of stimulus (signal)- stimulus usually different from transported molecule • Ex:ion-gated channels neurotransmitters bind to a specific gated channels on a neuron, these channels open = allows Na+ ions to enter nerve cell • Ex:voltage-gated channelschange in electrical charge across nerve cell membrane opens Na+ & K+ channels

31. Carriers and Channels are specific inside cell aa sugar H2O NH3 salt outside cell . . . BUT STILL MOVES FROM [HIGHER] to [LOWER]

32. Active transport Uses energy from ATP to move molecules against concentration gradient • Moves from [lower] → [higher] • Uses protein pumps OR vesicles Animations from:http://academic.brooklyn.cuny.edu/biology/bio4fv/page/cell-movement.html http://www.cat.cc.md.us/courses/bio141/lecguide/unit1/eustruct/images/sppump.gif

33. All cells have voltages across their membrane= membrane potential • Battery – affects traffic in the cell - Cytoplasm inside cell is more negative than extracellular fluid outside • TWO FORCES drive diffusion • Chemical force - Concentration gradient • Electrical force – ions • Ions move DOWN the electrochemical gradient Favors the passage of cations (+) into cells

34. MEMBRANE POTENTIAL created by electrogenic pumps (proteins that generate voltage by pumping ions) PROTON PUMPMain electrogenic pump in plants, fungi, and bacteria Na+- K+ PUMPMain electrogenic pump in animal cells http://fig.cox.miami.edu/~cmallery/150/memb/electrogenic.jpg Animation from: http://www.lionden.com/cell_animations.htm

35. Na+ - K+ pump sets up MEMBRANE POTENTIAL Resting Na+ in the cell is low, stimulated, flow in Ions and chemicals moving in SAME direction here. http://hyperphysics.phy-astr.gsu.edu/hbase/biology/nervecell.html#c2

36. Active transport SODIUM-POTASSIUM PUMP Sets up difference in charge across membranes Electrical force opposes Pumps 3 Na+ outand 2 K+ in Makes cells more + outside more - inside See a movieabout Na+ - K+ pump Animation from: http://www.cat.cc.md.us/courses/bio141/lecguide/unit1/eustruct/images/sppump.gif

37. PROTON PUMP Moves Protons (H+) across membrane EXAMPLES: - Creates acidic condition inside lysosomes - Photosynthesis/respiration use H+ gradients to generate ATP See a movie proton pump

38. Electrogenic pumps can be coupled to actively transport other substances = COTRANSPORT Ex: Cells pump H+out of cell then use the diffusion of H+back into cell to drivethe uptake of sucrose (nutrients) into cells http://faculty.southwest.tn.edu/rburkett/GB1-os29.jpg

39. BULK TRANSPORT Watch two video clips aboutendo/exocytosis endo/exocytosis • ACTIVE transport • Requires energy (ATP) • Uses vesicles Animation from: http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBooktransp.html

40. Endocytosis “Cell eating” large molecules; whole cells phagocytosis “Cell drinking” Fluids; Small molecules pinocytosis triggered byligand signal receptor-mediated endocytosis

41. PHAGOCYTOSIS Animation from: http://academic.brooklyn.cuny.edu/biology/bio4fv/page/cell-movement.html “Cell eating” takes in large molecules; whole cells See phagocytosis in action: http://www.accs.net/users/kriel/chapter%20nine/

42. Example in cells:WHITE BLOOD CELL ENGULFING BACTERIA using Phagocytosis SEE PHAGOCYTOSIS MOVIE http://fig.cox.miami.edu/~cmallery/255/255ion/fig14x28.jpg

43. PINOCYTOSIS “Cell drinking” Takes in fluids; Small molecules http://student.ccbcmd.edu/~gkaiser/biotutorials/eustruct/pinocyt.html

44. Receptor-mediated Endocytosis • Ligand-any molecule that binds to a receptor site • Binding of ligands allows uptake of specific molecules

45. Receptor-mediated Endocytosis Example in cells: Cholesterol Uptake Low density lipid proteins (LDL’s) bind cholesteroland carry it in blood LDL’s act as ligands bindingreceptors on cell surfaceand cholesterol is taken into cell http://academic.brooklyn.cuny.edu/biology/bio4fv/page/rectpr.htm

46. EXOCYTOSIS • Active transport (requires ATP) • Uses vesicles • Releases substances to outside INSULIN being released by pancreas cells using exocytosis

47. Video: http://www.southtexascollege.edu/tdehne/BC_ShockwaveAnimations/07SWF-TourOfTheCell/07-16-EndomembraneSystem.swf GOLGI BODIES USE EXOCYTOSIS Animation from: http://www.franklincollege.edu/bioweb/A&Pfiles/week04.html See a Golgi movie

48. http://fig.cox.miami.edu/~cmallery/255/255ion/fig14x26.jpg

49. Transport summary

50. Practice Test Answers Level One • B 2. C 3. D 4. B 5. A 6. C 7. C Level Two 3. A 4. C 5. C 6. B 9. D 10. B 11. A 12. A 13. B 14. C 15. C 16. B 17. B Grid In 1. 8000 um3 2. 8 3. -7.84 Bars