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Crossing the Cell membrane

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Presentation on theme: "Crossing the Cell membrane"— Presentation transcript:

1 Crossing the Cell membrane

2 Diffusion

3 Molecules move _______“where there’s _______” ____“where there’s ___________” Animatioin from: FROM TO A LOT NOT A LOT

4 DIFFUSION across a space Happens anytime there is a __________ in concentration in one place compared to another. This is called the_____________ DIFFERENCE Concentration gradient

5 DIFFUSION across a SPACE Molecules move automatically _______ the concentration gradient _______ an area of _______ concentration ____ an area of ________ concentration EXAMPLES Higher Lesser Blue dye in beaker demo, Kool Aid, DOWN from to someone making popcorn, grilling out, strong perfume, bad smell in room

6 DIFFUSION across a space Diffusion continues until the concentration is _________in space = ___________ Equilibrium ballanced

7 Kidspiration by: Riedell

8 Kinds of ________ Transport Ion Channel Osmosis Facilitated Diffusion __________________________________ ___________________________________ PASSIVE

9 Molecules need to move across membranes in cells Image modiified from:

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

11 DIFFUSION across a membrane Happens anytime there is a __________ in _____________ on one side of the membrane compared to the other difference Examples of molecules that move by diffusion across membranes in cells: OXYGEN, WATER, CARBON DIOXIDE, NITROGEN See diffusion animation concentration

12 DIFFUSION automatically moves oxygen from HIGHER concentration (in lungs) to a LOWER concentration (in blood) CELL EXAMPLE: CO 2 automatically moves from where there is a HIGHER concentration (in blood) to where there is a lower concentration (in lungs)


14 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

15 BUT…. What if a cell needs to move _____ or ______ molecules? LARGEPOLAR

16 Facilitated Diffusion _______ proteins help diffusion go faster Carrier MOVIE DIFFUSION ACROSS THE MEMBRANE (FACILITATED DIFFUSION)

17 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: AGAINST

18 What if cell needs to move molecules really _______? (can’t wait for it to diffuse) Cell example: Movement of Na + & K + ions required to send nerve signals FAST

19 We need a ____ to ____ molecules across cell membranes that _______ across by ___________ WAYHELP can’t go themselves

20 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

21 Facilitated Diffusion Animation from:

22 Kidspiration by: Riedell

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

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

25 Sodium (Na+)- Potassium (K+) Pump Animation from: See a movie See a movie about Na+ - K+ pump

26 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

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

28 ENDOCYTOSIS Takes substances into cell _____________transport (requires __________ from ______) Uses small membrane sacs called ______________ to carry substances ACTIVE VESICLES energy ATP

29 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

30 Pinocytosis Called “Cell Drinking”Called “Cell Drinking”

31 ENDOCYTOSIS Animation from:

32 PHAGOCYTOSIS ___________ destroying _______ White blood cell germs Called “Cell Eating”

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

34 Exocytosis

35 GOLGI BODIES USE EXOCYTOSIS Animation from: See a Golgi movie Video:

36 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:

37 INSULIN being released by pancreas cells using exocytosis

38 What if there is a difference in concentration but solute molecules can’t move across a membrane? WATER will move until concentration reaches equilibrium

39 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

40 __________________ = 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

41 See a video clip about OSMOSIS -7B

42 See an animation Osmosis1 Osmosis1 Animation:

43 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:

44 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

45 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:

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

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

48 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

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

50 Animal cells

51 Osmosis in Red Blood Cells Isotonic Hypotonic Hypertonic

52 Plant cells CELL WALL _____ keeps Plant cells from bursting

53 VACUOLES store WATER _____________________________ = Pressure exerted by water during osmosis OSMOTIC PRESSURE

54 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

55 Grocery stores spray water on their veggies to “plump them up”


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