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The Plasma Membrane The Plasma Membrane - Gateway to the Cell.

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Presentation on theme: "The Plasma Membrane The Plasma Membrane - Gateway to the Cell."— Presentation transcript:

1 The Plasma Membrane The Plasma Membrane - Gateway to the Cell

2 Photograph of a Cell Membrane

3 Types of Transport Across Cell Membranes

4 Simple Diffusion NORequires NO energy HIGH to LOWMolecules move from area of HIGH to LOW concentration

5 DIFFUSION PASSIVE Diffusion is a PASSIVE process which means no energy is used to make the molecules move, they have a natural KINETIC ENERGY

6 Diffusion of Liquids

7 Diffusion through a Membrane Cell membrane Solute moves DOWN concentration gradient (HIGH to LOW)

8 Osmosis Diffusion of water across a membraneDiffusion of water across a membrane Moves from HIGH water potential (low solute) to LOW water potential (high solute)Moves from HIGH water potential (low solute) to LOW water potential (high solute) Diffusion across a membrane Semipermeable membrane

9 Diffusion of H 2 O Across A Membrane High H 2 O potential Low solute concentration Low H 2 O potential High solute concentration

10 Cell in Isotonic Solution CELL 10% NaCL 90% H 2 O 10% NaCL 90% H 2 O What is the direction of water movement? The cell is at _______________. equilibrium ENVIRONMENT NO NET MOVEMENT

11 Cell in Hypotonic Solution CELL 10% NaCL 90% H 2 O 20% NaCL 80% H 2 O What is the direction of water movement?

12 Cell in Hypertonic Solution CELL 15% NaCL 85% H 2 O 5% NaCL 95% H 2 O What is the direction of water movement? ENVIRONMENT

13 Cells in Solutions

14 Isotonic Solution NO NET MOVEMENT OF H 2 O (equal amounts entering & leaving) Hypotonic Solution CYTOLYSIS Hypertonic Solution PLASMOLYSIS

15 Cytolysis & Plasmolysis Cytolysis Plasmolysis

16 Osmosis in Red Blood Cells Isotonic Hypotonic Hypertonic

17 hypotonichypertonic isotonic hypertonicisotonic hypotonic

18 Three Forms of Transport Across the Membrane

19 Passive Transport Simple Diffusion Doesnt require energy Doesnt require energy Moves high to low concentration Moves high to low concentration Example: Oxygen or water diffusing into a cell and carbon dioxide diffusing out Example: Oxygen or water diffusing into a cell and carbon dioxide diffusing out.

20 Passive Transport Facilitated diffusion Doesnt require energy Uses transport proteins to move high to low concentration Examples: Glucose or amino acids moving from blood into a cell.

21 Proteins Are Critical to Membrane Function

22 Active Transport Requires energy or ATP Moves materials from LOW to HIGH concentration AGAINST concentration gradient

23 Active transport Examples: Pumping Na + (sodium ions) out and K + (potassium ions) in against strong concentration gradients. Called Na+-K+ Pump

24 Sodium-Potassium Pump 3 Na+ pumped in for every 2 K+ pumped out; creates a membrane potential

25 Moving the Big Stuff Molecules are moved out of the cell by vesicles that fuse with the plasma membrane. Exocytosis Exocytosis - moving things out. This is how many hormones are secreted and how nerve cells communicate with one another This is how many hormones are secreted and how nerve cells communicate with one another.

26 Exocytosis Exocytic vesicle immediately after fusion with plasma membrane.

27 Moving the Big Stuff Large molecules move materials into the cell by one of three forms of endocytosis Large molecules move materials into the cell by one of three forms of endocytosis.

28 Pinocytosis Most common form of endocytosis Most common form of endocytosis. Takes in dissolved molecules as a vesicle Takes in dissolved molecules as a vesicle.

29 Pinocytosis Cell forms an invaginationCell forms an invagination Materials dissolve in water to be brought into cellMaterials dissolve in water to be brought into cell Called Cell DrinkingCalled Cell Drinking

30 Example of Pinocytosis pinocytic vesicles forming mature transport vesicle Transport across a capillary cell (blue).

31 Receptor-Mediated Endocytosis Some integral proteins have receptors on their surface to recognize & take in hormones, cholesterol, etc.

32 Receptor-Mediated Endocytosis

33 Endocytosis – Phagocytosis Used to engulf large particles such as food, bacteria, etc. into vesicles Called Cell Eating

34 Phagocytosis About to Occur

35 Phagocytosis Phagocytosis - Capture of a Yeast Cell (yellow) by Membrane Extensions of an Immune System Cell (blue)

36 Exocytosis The opposite of endocytosis is exocytosis. Large molecules that are manufactured in the cell are released through the cell membrane. Inside Cell Cell environment

37 OSMOSIS http://www.biology4kids.com/files/cell_main.html

38 Diffusion http://lhs.lps.org/staff/sputnam/Biology/U3Cell/diffusion_1.png

39 See a video clip about DIFFUSION-7A

40 Molecules move _______where theres _______ ____where theres _______ Animatioin from: http://www.biologycorner.com/resources/diffusion-animated.gif FROM to A LOT NOT

41 DIFFUSION across a space Happens anytime there is a __________ in concentration in one place compared to another = ________________________ DIFFERENCE Concentration gradient

42 DIFFUSION across a SPACE Molecules move automatically _______ the concentration gradient _______ an area of _______ concentration ____ an area of ________ concentration EXAMPLES Higher Lower Blue dye in beaker demo, Someone making popcorn/grilling out Strong perfume, Bad smell in room http://www.swapmeetdave.com/Humor/Farts.htmhttp://leighhouse.typepad.com/blog/images/kool_aid.jpg DOWN from to

43 DIFFUSION across a space Diffusion continues until the concentration is ________________ in space = ________________________ Equilibrium http://lhs.lps.org/staff/sputnam/Biology/U3Cell/diffusion_1.png equal everywhere

44 Molecules need to move across membranes in cells Image modiified from: http://www.accessexcellence.org/AB/GG/importProt.html

45 Diffusion can happen ________ a _____________ in a cell, too …as long as membrane will let the molecule _________________ across membrane pass through

46 SELECTIVELY PERMEABLE (Semi-permeable) http://life.nthu.edu.tw/~d857401/advance.html See a movie Video from: http://www.southtexascollege.edu/tdehne/BC_ShockwaveAnimations/08SWF-MembraneStructureAndFunct/08-02-MembraneStructure.swf

47 DIFFUSION automatically moves oxygen from HIGHER concentration (in lungs) to a LOWER concentration (in blood) http://www.le.ac.uk/pa/teach/va/anatomy/case2/2_2.html CELL EXAMPLE: CO 2 automatically moves from where there is a HIGHER concentration (in blood) to where there is a lower concentration (in lungs)

48 BUT…. What if a cell needs to move _____ or ______ molecules? http://www.d.umn.edu/~sdowning/Membranes/membraneImages/jpegimages/diffusionmedium.jpg LARGEPOLAR

49 What if cell needs to move a molecule _________ the CONCENTRATION GRADIENT? _______________ 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 AGAINST

50 What if cell needs to move molecules really _______? (cant wait for it to diffuse) Cell example: Movement of Na + & K + ions required to send nerve signals http://www.steve.gb.com/images/science/neuron.png FAST

51 We need a ____ to ____ molecules across cell membranes that _______ across by ___________ WAYHELP cant go themselves

52 Kidspiration by: Riedell

53 Kinds of ________ Transport Diffusion Osmosis Facilitated Diffusion __________________________________ ___________________________________ PASSIVE

54 DIFFUSION across a membrane Happens anytime there is a __________ in _____________ on one side of the membrane compared to the other DIFFERENCE Molecules that move by diffusion across membranes in cells: ______________ OXYGEN CARBON DIOXIDE http://www.lionden.com/cell_animations.htm See diffusion animation concentration

55 OSMOSIS = SPECIAL KIND OF DIFFUSION IMAGE by RIEDELL See osmosis animation ____________ __________ OSMOSIS DIFFUSION Movement of molecules across a _________________ membrane from ______ concentration to _____ Semi-permeable Higher lower

56 See a video about Passive transport 7-C

57 Facilitated Diffusion _______ proteins help diffusion go faster Carrier

58 FACILITATED DIFFUSION No energy required = __________________ Moves _________ concentration gradient from ________________________ _____________________ grab molecule, change shape, and flip to other side (Like a revolving door) Molecules that move this way in cells: _______________________ PASSIVE Membrane proteins GLUCOSE HIGHER to LOWER DOWN

59 Facilitated Diffusion Animation from: http://bio.winona.edu/berg/ANIMTNS/facdifan.gif

60 Kidspiration by: Riedell

61 Kinds of ________Transport Sodium-Potassium Pump Endocytosis Exocytosis ________________________________________ ___________________________________ ____________________________________ ACTIVE

62 See a video clip about Na + -K + pump -7D

63 Sodium (Na+)- Potassium (K+) Pump Animation from: http://www.lionden.com/cell_animations.htm See a movie See a movie about Na+ - K+ pump

64 Sodium-Potassium pump ___________ transport (requires energy from ______) Special just for Na + and K + ions Uses integral ___________________ to move molecules Examples in nerve cells: Na + is pumped out of cells at same time K + is taken into cells ACTIVE Carrier Proteins ATP

65 See a video clip about Endo/exocytosis -7E

66 ENDOCYTOSIS Takes substances into cell _____________transport (requires __________ from ______) Uses small membrane sacs called ______________ to carry substances ACTIVE VESICLES http://www.sirinet.net/~jgjohnso/cell.html energy ATP

67 2 KINDS of ENDOCYTOSIS Takes substances into cell If taking in: fluid or small molecules =_________________ large particles or whole cells =______________ Examples in cells: –one celled organisms eat this way –white blood cells get rid of bacteria this way PINOCYTOSIS PHAGOCYTOSIS

68 Pinocytosis Called Cell DrinkingCalled Cell Drinking

69 ENDOCYTOSIS Animation from: http://academic.brooklyn.cuny.edu/biology/bio4fv/page/cell-movement.html http://www.accs.net/users/kriel/chapter%20nine/

70 PHAGOCYTOSIS ___________ destroying _______ White blood cell germs Called Cell Eating

71 EXOCYTOSIS Substances released outside of cell __________ transport (requires __________) Substances move in____________ Examples in cells: –_________ release packaged proteins this way ACTIVE VESICLES energy GOLGI

72 Exocytosis http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBooktransp.html

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

74 Endocytosis & Exocytosis Watch a video clip about endo/exocytosis endo/exocytosis Watch a video clip about endo/exocytosisendo/exocytosis Choose Screen/Switch programs to view Videos from: http://www.pleasanton.k12.ca.us/avhsweb/thiel/apbio/notes/chp8/exocytosis_endocytosis.mov http://trc.ucdavis.edu/biosci10v/bis10v/week2/endocytosis.mov

75 INSULIN being released by pancreas cells using exocytosis http://fig.cox.miami.edu/~cmallery/255/255ion/fig14x26.jpg

76 What if there is a difference in concentration but solute molecules cant move across a membrane? WATER will move until concentration reaches equilibrium

77 VOCAB _____________ = substance that is dissolved in a solvent to make a solution _____________ = substance in which a solute is dissolved SOLUTE EX: Koolaid powder = solute Water = solvent Koolaid drink = solution SOLVENT http://www.makash.ac.il/h_school/hst/hstsb/chem/luach/dissolve.jpg

78 __________________ = mass of a solute in a given volume of solution CONCENTRATION The _______ molecules there are in a given volume the ____________the concentration Images by Riedell MORE GREATER

79 See a video clip about OSMOSIS -7B

80 See an animation Osmosis1 Osmosis1 http://faculty.etsu.edu/currie/images/osmosis1.jpg Animation: http://www.ouhscphysio.org/humanphys/animations/osmosis1.swf

81 OSMOSIS HYPERTONIC: Concentration outside cell is ____________________ inside cell More water leaves cell than enters so cell ____________ GREATER THAN shrinks See an animation OSMOSIS 4 Animation from: http://www.ouhscphysio.org/humanphys/animations/osmosis4.swf

82 Cell in Hypertonic Solution CELL 15% NaCL 85% H 2 O 5% NaCL 95% H 2 O What is the direction of water movement? ENVIRONMENT

83 OSMOSIS HYPOTONIC: Concentration outside cell is ________________ inside the cell More water enters than leaves cell so cell will ___________________ LESS THAN Swell and possibly burst See an animation Osmosis3 Osmosis3 Animation from: http://www.ouhscphysio.org/humanphys/animations/osmosis3.swf

84 Cell in Hypotonic Solution CELL 10% NaCL 90% H 2 O 20% NaCL 80% H 2 O What is the direction of water movement?

85 OSMOSIS ISOTONIC: Concentration outside cell __________ concentration inside cell Water entering = water leaving so cell _____________________ EQUALS STAYS THE SAME SIZE

86 Cell in Isotonic Solution CELL 10% NaCL 90% H 2 O 10% NaCL 90% H 2 O What is the direction of water movement? The cell is at _______________. equilibrium ENVIRONMENT NO NET MOVEMENT

87 Isotonic Solution NO NET MOVEMENT OF H 2 O (equal amounts entering & leaving) Hypotonic Solution Cell Swells & may burst Hypertonic Solution Cell shrivels up

88 Animal cells http://www.stchs.org/science/courses/sbioa/metenergy/bloodcells.gif

89 Osmosis in Red Blood Cells Isotonic Hypotonic Hypertonic

90 Plant cells http://www.stchs.org/science/courses/sbioa/metenergy/aplantturgor.gif CELL WALL _____ keeps Plant cells from bursting

91 VACUOLES store WATER http://www.biology4kids.com/files/cell_vacuole.html _____________________________ = Pressure exerted by water during osmosis OSMOTIC PRESSURE

92 SO WHAT? Sitting in the bathtub causes your fingers and toes to wrinkle up when water ________ your skin cells by osmosis Bath water is ________________ compared to you hypotonic enters

93 Grocery stores spray water on their veggies to plump them up http://www.painetworks.com/photos/gt/gt0461.JPG

94 SO WHAT?


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