1. Chapter 5 Transfer of Materials Across Cell Boundaries
To remain alive and function optimally, cells must maintain a biological balance with their immediate environment. They must remain stable.
This biological balance is called __________.
Cell membranes help organisms maintain homeostasis by controlling what substances may enter or leave the cell. Membrane- Covers and Protects the inside from the outside!
And, what is this term?? ______-___________
Homeostasis
Equilibrium
semi-permeable

2. The Cell Membrane - Gateway to the Cell Integral or Channel
The Plasma Membrane
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The Cell Membrane -
Peripheral Proteins
Integral or Channel
Hydrophobic
hydrophilic
Gateway to the Cell
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3. The Plasma Membrane
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FLUID MOSAIC MODEL
FLUID- because individual phospholipids and proteins can move side-to-side within the layer, like it’s a liquid.
MOSAIC- because of the pattern produced by the scattered protein molecules when the membrane is viewed from above
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4. Cell Membrane Polar heads are hydrophilic “water loving”
The Plasma Membrane
Cell Membrane
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Polar heads are hydrophilic “water loving”
Nonpolar tails are hydrophobic “water fearing”
Makes membrane “Selective” in what crosses
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5. The Plasma Membrane
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Types of Transport Across Cell Membranes 1) Passive no NRG 2) Active  with NRG
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6. Passive Transport : Energy=ATP
the movement of substances from across a membrane without the use of chemical
Will go from High to a low concentration
From where there is a lot to a little
Energy=ATP
4 types: Diffusion & Facilitated Diffusion, osmosis (water), ion channels

7. concentration gradient
Difference in concentration of molecules….goes from there is a lot to where there is none
Diffusion
The movement of a substance from an area of _______ concentration to an area of _____ concentration (down a ) without a membrane
Caused by the random movement of particles
They have a natural Kinetic NRG
A. ____________
HIGH
LOW
concentration gradient

9. Fig. 5.8, p. 80

10. smaller 3. diffusion of substance across the membrane depends on
Temperature:
__________ temperature = __________ diffusion
b. Size:
_______ molecules diffuse faster
c. Type of molecule:
lipids diffuse through easily;
electrically charged ions or large particles will not
smaller

11. 4. ___________ is reached when the concentration in the cell is equal to the concentration outside the cell; All Passive transport will eventually end here…(keep on moving till all spread out)
at that point molecules will diffuse at the same rate they diffuse out
Equilibrium

12. OSMOSIS water = solution
osmosis = diffusion of ________ across a semi-permeable membrane;
occurs in response to concentration of solutes dissolved in water Goes From High Water Potential (low Solute) to Low Water Potential (High Solute)….from where there is a lot of water to where there is little amount of water
water
SOLUTE
SOLVENT
= solution

13. Diffusion of H2O Across A Membrane
The Plasma Membrane
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Diffusion of H2O Across A Membrane
Solute
High H2O potential Low solute concentration
Low H2O potential High solute concentration
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14. O E HYPOTONIC (low solute concentration, a lot of water) Hypertonic
(high solute concentration, little water)
O E
If one side is hypotonic the other has to be the opposite (hypertonic)….will keep moving water until EQUILIBRIUM is reached……..At which point inside and outside are both ISOTONIC toward each other!!!! (water still moving but at same rate in and out)

15. Diffusion of H2O Across A Membrane
The Plasma Membrane
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Diffusion of H2O Across A Membrane
Hypertonic
Hypotonic E
High H2O potential Low solute concentration
Low H2O potential High solute concentration
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16. Cell shrivels and shrinks
Conditions
Environment is
Inside Cell is
Water will move
Results
If solute conc. in the environment is lower than in cell
Cell swells, may burst
Animal = Cytolysis
Plant = Turgor Pressure
If solute conc. in the env. is higher than in the cell
If solute conc in the env is equal to that of the cell
Into and out of cell at equal rates
No net movement
Hypertonic
into cell
Hypotonic
Cell shrivels and shrinks
Animal = Crenation
Plant = Plasmolysis
Hypertonic
(hyper = high)
Out of cell
Hypotonic
Isotonic
(iso =)
Isotonic

18. turgor pressure
plasmolysis
Fig. 5.24, p. 89

19. A Paramecium lives in a freshwater environment
Water is always diffusing into these organisms
They need a low water concentration
So they are always pumping water out of themselves with a contractile vacuole

20. Why do we salt our foods to preserve them?
Why do we gargle with salt water for soar throats?
Salted foods – kill bacteria on it because their water component is removed from them due to osmosis
Kills bacteria on contact (like salted food example)
Some of pain is due to swelling of tissue which is accumulation of fluids so adding salt will remove from fluid
The salt water is what to these cells?
ANS: Hypertonic - (salt water has a higher solute concentration)

21. Cell in Hypotonic Solution
The Plasma Membrane
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Cell in Hypotonic Solution
10% NaCL 90% H2O
CELL
20% NaCL
80% H2O
What is the direction of water movement? 21
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22. Cell in Isotonic Solution
The Plasma Membrane
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Cell in Isotonic Solution
10% NaCL 90% H2O
ENVIRONMENT
CELL
NO NET MOVEMENT
10% NaCL
90% H2O
What is the direction of water movement?
equilibrium
The cell is at _______________. 22
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23. Cell in Hypertonic Solution
The Plasma Membrane
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Cell in Hypertonic Solution
15% NaCL 85% H2O
ENVIRONMENT
CELL
5% NaCL
95% H2O
What is the direction of water movement? 23
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24. NO NET MOVEMENT OF H2O (equal amounts entering & leaving)
The Plasma Membrane
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Isotonic Solution
Hypotonic Solution
Hypertonic Solution
NO NET MOVEMENT OF H2O (equal amounts entering & leaving)
Crenate
CYTOLYSIS
Turgor pressure
PLASMOLYSIS
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25. Facilitated B.___________ Diffusion
used for molecules that can’t diffuse rapidly through cell membrane; ex: glucose….need helpers
(too large or not soluble in lipid layer)
Still will go from ………

26. Types of Transport Proteins
The Plasma Membrane
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Types of Transport Proteins
Channel proteins are embedded in the cell membrane & have a pore for materials to cross…open through middle
Carrier proteins can change shape to move material from one side of the membrane to the other 26
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27. Releases into/out of cell
Binds to molecule
Changes shape shields molecule from interior of membrane
Releases into/out of cell

28. Ion allow passage of important ions (Na+, K+, Cl-, Ca2+);
C. _____ channels:
allow passage of important ions (Na+, K+, Cl-, Ca2+);
some are always open, specific to ion
some have “gates” that open and close in response to: stretching of membrane, electrical signals, or chemicals
Ion

30. Active energy from LOW to HIGH
II Transport- the use of (ATP) to transport materials through the cell membrane against the concentration gradient
energy
from LOW to HIGH

31. A. Cell Membrane Protein Pumps -
proteins embedded in cell membrane; use energy to move ions and large molecules across the membrane against the gradient…low to high…little to a lot

32. Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ Ca++ P Ca++ P ADP ATP
ENERGY
INPUT
Fig. 5.6c, p. 79

33. B. Sodium-Potassium Pump –
Important in muscle contraction and nerve impulses
3 Na+ (sodium) OUT
2 K+ (potassium) IN
Y2K
Im sodium, can I come in?

35. C. Proton Pump - chemiosmosis
Transports protons (Hydrogen +) across the membranes of mostly in mitochondria and chloroplasts
Use to make ATP =
chemiosmosis

36. low conc. H H+ H+ H+ H+ H+ H+ H+ H+ high conc. H Proton Pump will
Pump H+’s against
flow
low conc. H H+
Lipid bilayer H+
Outside mito
Inside mito H+ H+ H+ H+ H+ H+
high conc. H
So that they can flow easy “down” their gradient

37. This protein CAPTURES THIS KINETIC ENERGY to make ATP
Outside cell
Inside cell H+ H+ H+ H+ H+ H+

38. D. Endocytosis  EN Enter Cell
folding in of membrane to form vesicles
Two types
Phagocytosis
Pinocytosis

39. Endocytosis – Phagocytosis
The Plasma Membrane
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Endocytosis – Phagocytosis
Used to engulf large particles such as food, bacteria (whole organisms), etc. into vesicles
Called “Cell Eating” 39
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40. Pinocytosis Most common form of endocytosis.
The Plasma Membrane
Pinocytosis
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Most common form of endocytosis.
Takes in dissolved (solutes or fluids) molecules as a vesicle. 40
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41. E. ExocytosisEXEXIT
removes wastes and cell products packaged by Golgi vesicles

42. Exocytosis- moving things out.
The Plasma Membrane
Moving the “Big Stuff”
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Exocytosis- moving things out.
Molecules are moved out of the cell by vesicles that fuse with the plasma membrane.
This is how many hormones are secreted and how nerve cells communicate with one another. 42
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43. endocytic vesicle forming
plasma membrane
exocytic vesicle leaving cytoplasm
endocytic
vesicle
forming
Fig. 5.20, p. 87

44. The Plasma Membrane
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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 44
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