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Moving through the Plasma Membrane

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Moving through the Plasma Membrane Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell Hypotonic In Swells, then bursts (cytolysis ... – PowerPoint PPT presentation

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Title: Moving through the Plasma Membrane


1
Moving through the Plasma Membrane
2
What does a phospholipid look like?
3
Lets Review
  • What is homeostasis?
  • What is the job of the plasma membrane?
  • How do you think the cell membrane helps a cell
    maintain homeostasis?

4
What does the Plasma Membrane look like?
Outside Cell (Extracellular Matrix)
Protein
Glycoprotein
Phospholipids
Cholesterol
Inside Cell (Cytoplasm)
5
The Plasma Membrane
Outside Cell (Extracellular Matrix)
Protein
Glycoprotein
Phospholipids
Cholesterol
Inside Cell (Cytoplasm)
6
The Plasma Membrane
Polar
Non-Polar
Outside Cell (Extracellular Matrix)
Protein
Glycoprotein
Phospholipids
Cholesterol
Inside Cell (Cytoplasm)
7
Plasma MembraneThe Fluid Mosaic Model
8
Plasma MembraneThe Fluid Mosaic Model
  • Fluid because
  • the phospholipid and protein molecules are able
    to move around. Not stuck in one place.
  • Mosaic because
  • the membrane contains a variety of proteins
    embedded with the phospholipids.

9
How do particles move in and out of the cell?
10
Passive Transport
energy
  • No additional _______________ is required because
    every particle has its own energy
  • This energy produces ________________ movement in
    particles. (a.k.a Brownian motion)

random
11
Diffusion
  • Diffusion is the movement of substances from a
    ________ concentration to a low concentration.
  • Diffusion is caused by __________ __________
  • Concentration is the _________ of something in a
    given ______.

high
Brownian Motion
amount
area
12
How does it work?
  • Particles move down the concentration gradient,
    until the concentration is _________ throughout
    an area.
  • Then the system is said to have reached dynamic
    equilibrium.

equal
13
A.
High Concentration of Orange Dots Low
Concentration of Blue Dots
High Concentration of Blue Dots Low Concentration
of Orange Dots
B.
System has reached dynamic equilibrium
14
Examples of diffusion at work
  • Why does food smell fragrant when cooked?
  • Have you ever stood next to someone wearing
    strong perfume?

15
Permeability of a membrane
  • Permeable anything can pass through
  • Semi-permeable some things can pass through
  • Impermeable nothing can pass through

16
Back to the plasma membrane
Outside Cell (Extracellular Matrix)
Inside Cell (Cytoplasm)
17
  • The plasma membrane is described as
    semi-permeable because some substances can move
    through it
  • Small and
  • Non-polar

18
Osmosis
  • Diffusion of _________ across a membrane
  • Water molecules can pass through pores or
    openings created by __________ in the plasma
    membrane .

water
proteins
19
Back to the plasma membrane
Outside Cell (Extracellular Matrix)
Protein
Glycoprotein
Phospholipids
Cholesterol
Inside Cell (Cytoplasm)
20
The Cells Environment Isotonic
  • In an isotonic environment the solute
    concentrations are ___________ and there is no
    NET movement of water.

equal
21
The Cells Environment Hypotonic
  • In a hypotonic environment, there are __________
    solutes outside than inside and water moves into
    the cell.

less
22
The Cells Environment Hypertonic
  • In a hypertonic environment there are _________
    solutes outside than inside and water moves out
    of the cell.

more
23
Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell
Hypotonic
Hypertonic
Isotonic
24
Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell
Hypotonic In Swells, then bursts (cytolysis)
Hypertonic
Isotonic
25
Animal Cell Cytolysis
Cells burst
Cell still intact
26
Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell
Hypotonic In Swells, then bursts (cytolysis) Swells, increases turgor pressure
Hypertonic
Isotonic
27
Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell
Hypotonic In Swells, then bursts (cytolysis) Swells, increases turgor pressure
Hypertonic Out
Isotonic
28
Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell
Hypotonic In Swells, then bursts (cytolysis) Swells, increases turgor pressure
Hypertonic out Shrinks (crenation)
Isotonic
29
Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell
Hypotonic In Swells, then bursts (cytolysis) Swells, increases turgor pressure
Hypertonic out Shrinks (crenation) Shrink (plasmolysis)
Isotonic
30
Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell
Hypotonic In Swells, then bursts (cytolysis) Swells, increased turgor pressure
Hypertonic Out Shrinks (crenation) Shrinks, (plasmolysis)
Isotonic
31
Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell
Hypotonic In Swells, then bursts (cytolysis) Swells, increases turgor pressure
Hypertonic out Shrinks (crenation) Shrink (plasmolysis)
Isotonic
32
Plant cell Plasmolysis
Plasmolyzed Cells
Normal cells
33
Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell
Hypotonic In Swells, then bursts (cytolysis) Swells, increases turgor pressure
Hypertonic out Shrinks (crenation) Shrink (plasmolysis)
Isotonic In and out at the same rate
34
Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell
Hypotonic In Swells, then bursts (cytolysis) Swells, increases turgor pressure
Hypertonic out Shrinks (crenation) Shrink (plasmolysis)
Isotonic In and out at the same rate Stays the same
35
Environment outside cell Water moves Effect on ANIMAL cell Effect on PLANT cell
Hypotonic In Swells, then bursts (cytolysis) Swells, increases turgor pressure
Hypertonic out Shrinks (crenation) Shrink (plasmolysis)
Isotonic In and out at the same rate Stays the same Stays the same
36
(No Transcript)
37
Osmosis in Action
  • What happens when you sprinkle salt on a slug?
  • If you are stranded at sea and run out of water,
    should you drink sea water?
  • Water moves from a hypo to a hypertonic
    environment.

38
True or False
  1. In diffusion, particles move from an area of high
    to low concentration.
  2. Diffusion does not require any additional energy
    to occur.
  3. Small, charged or polar particles can move
    through the cell membrane by simple diffusion.

39
  • What if a cell needs large or charged/ polar
    molecules. Can they move across the membrane?
  • Yes!

40
Selectively Permeable Membrane
  • The cell membrane picks what molecules can
    enter and exit the cell because proteins in the
    membrane allow specific macromolecules or ions in
    or out of the cell.

41
Facilitated diffusion
  • Proteins help particles move across the membrane
  • Transport proteins span the phospholipid bilayer,
    but allow only ___________ molecules through.
  • gtgt Selectivity

specific
42
Types of transport proteins
Ion channels
  • ____ __________ are nonpolar on the outside and
    polar on the inside. They provide a pore for
    ions and polar particles to move through.

43
Carrier Proteins
  • _________ _______________ bind to specific
    particles, carry them through the membrane, and
    release them on the other side.
  • http//www.stolaf.edu/people/giannini/flashanimat/
    transport/caryprot.swf

44
Remember!
  • In diffusion-particles (solutes) move from an
    area of HIGH concentration to LOW In osmosis-
    water moves from a HYPOTONIC environment to a
    HYPERTONIC environment
  • Diffusion requires NO energy input
  • http//scienceguyinatie.blogspot.com/2008/11/cell-
    membrane-animation-of-word-wall.html

45
Simple vs. Facilitated
  • In simple diffusion, particles move between
    phospholipid molecules of the membrane.
  • In facilitated diffusion, particles move through
    transport proteins in the membrane.
  • Both do NOT use energy. Particles must move down
    the concentration gradient.

46
  • But what if you needed to move particles against
    their concentration gradient?

47
Active Transport
  • Transport proteins use ________to move particles
    against their concentration gradient, from a low
    concentration to a high concentration.

energy
48
Sodium-Potassium Pump
  • Carrier- protein that pumps 3 sodium ions
    (Na)________ the cell, while pumping
    2 potassium ions (K)________.

outside
inside
http//highered.mcgraw-hill.com/sites/0072495855/s
tudent_view0/chapter2/animation__how_the_sodium_po
tassium_pump_works.html
http//www.brookscole.com/chemistry_d/templates/st
udent_resources/shared_resources/animations/ion_pu
mp/ionpump.html
49
  1. 3 Na ions from inside the cell bind to the pump
    protein. Energy from ATP is added to the protein.
  2. The Na ions are moved to the outside of the
    cell.
  3. The 3 Na ions are released and 2 K ions bind to
    the protein.
  4. The protein changes back and releases the 2 K
    ions into the cell.

50
Vesicle Mediated Transport
  • The fluid plasma membrane can pinch off
    forming vesicles that can move very
    _______particles or lots of ______particles.
  • This process needs _______.

large
small
energy
51
Endocytosis
  • Outside materials are brought __________ the
    cell.

inside
3) Vesicle with food
1) Food particle
2) Pouch forming around food
52
Endocytosis
  • Phagocytosis
  • Cell eating
  • Cell engulfs large food particles and the vesicle
    is a food vacuole.
  • http//www.stolaf.edu/people/giannini/flashanimat/
    cellstructures/phagocitosis.swf
  • Pinocytosis
  • cell drinking
  • Cell engulfs small droplets of surrounding fluid.

53
Exocytosis
  • Material from inside the cell is released
    _________ by vesicles.

outside
1) Vesicle fuses with membrane
3) Particle released
2) Pouch opens
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