1. “You are what you eat” Knowing what you do about the cell
membrane do you agree or disagree
with this statement and why?

2. Cell Transport

3. Passive Transport
Movement across a cell membrane that does not require energy from the cell

4. Concentration GREATER
A measure of the amount of dissolved substance contained per unit of volume
MORE
The _______ molecules there are in a given volume the ____________the concentration
GREATER

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

6. Concentration Gradient
DIFFERENCE
Anytime there is a __________ in concentration in one place compared to another

7. DIFFUSION
Molecules move automatically (random motion) _______ the concentration gradient _______ an area of _______ concentration ____ an area of ________ concentration
DOWN
from
Higher to
Lower

8. DIFFUSION Equilibrium
Diffusion continues until the concentration is ________________ in space
= ________________________
equal everywhere
Equilibrium

9. Molecules and ions need to move across membranes in cells

10. Diffusion happens ________ a _____________ in a cell, too
across
membrane
…as long as the membrane will let the molecule _________________
pass through

11. DIFFUSION
Concentration gradient between the inside and outside of the cell
Small and/or nonpolar molecules (ex. O2, CO2, H2O) can diffuse across the membrane down the concentration gradient

12. DIFFUSION
DIFFUSION automatically moves oxygen from HIGHER concentration (in lungs) to a LOWER concentration (in blood)
CO2 automatically moves from where there is a
HIGHER concentration
(in blood) to where there
is a lower concentration
(in lungs)

13. Facilitated Diffusion
A type of passive transport
It moves substances down their concentration gradient without using the cell’s energy
Uses Carrier Proteins and Channels

14. FACILITATED DIFFUSION uses _______________ to help molecules across 2 kinds of proteins help: _________ & ____________
membrane proteins
Carriers
Channels

15. Facilitated Diffusion with CARRIER PROTEINS
grabs molecule,
changes shape, and
flips across to
other side like a
revolving door

16. FACILITATED DIFFUSION with CHANNELS
Membrane
proteins
create a
tunnel through
which molecules
can pass
ION CHANNELS
charged
_______________ allow________ ions to get past the ____________ center
hydrophobic

17. Ion Channel
A transport protein with a polar pore through which ions can pass

18. Ion Channel
The inside of a typical cell is negatively charged with respect to the outside of the cell
A positively charged ion outside the cell is more likely to diffuse into the cell

19. Osmosis
The diffusion of water through a selectively permeable membrane
Water molecules are small and diffuse through the cell membrane

20. Example: gargling with salt water
Osmosis
Example: gargling with salt water

21. _____________ = substance that is dissolved in a solvent to make a solution
_____________ = substance in which a solute is dissolved
SOLUTE
SOLVENT

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

25. Cells try to “maintain stable internal conditions =__________________
HOMEOSTASIS
If cells can’t maintain
“stable internal conditions” . . .
damage can result and cells can die.

26. Solute concentration Greater outside than inside Lower outside
Equal outside
and inside
HYPERTONIC
HYPOTONIC
ISOTONIC

27. OSMOSIS
HYPOTONIC: Concentration outside cell is ________________ inside the cell More water enters than leaves cell so cell will ___________________
LESS THAN
swell and possibly burst

28. OSMOSIS
A cell in
ISOTONIC conditions
stays same size

29. OSMOSIS shrinks GREATER THAN
HYPERTONIC: Concentration outside cell is ____________________ inside cell
More water leaves cell than enters so cell ____________
GREATER THAN
shrinks

30. What happens if a plant cell is placed in a hypotonic, isotonic, or hypertonic solution?

31. hypotonic Bath water is a _________ solution enters
Sitting in the bathtub causes your fingers and toes to wrinkle up when water ________ your skin cells by osmosis
enters

32. PROBLEM for CELLS? Diffusion only moves molecules from high concentration to low concentration Diffusion happens slowly Diffusion to some extent only works if substance can pass through cell membrane

33. PROBLEM for Cells? Cell membranes are SELECTIVELY PERMEABLE

34. What if cell needs to move a molecule _________ the CONCENTRATION GRADIENT? _______________
AGAINST
(LOWER  HIGHER)
For example if you want
to put MORE glucose
into mitochondria when there is
already glucose in there

35. What if cell needs to move molecules really _______
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

36. What if a cell needs to move _____ or ______ molecules that can’t get through the membrane?
LARGE
POLAR

37. Cells need _____ to ____ molecules across cell membranes that _______ across by ___________
WAYS
HELP
can’t go
themselves

38. Active Transport
Transport of a substance across the cell membrane against its concentration gradient
Requires the cell to use energy (comes directly or indirectly from ATP)

39. ________________ and ___________ help molecules to cross cell membranes
Membrane proteins
vesicles

40. Active Transport
Some active-transport processes involve carrier proteins
Function as pumps

41. Sodium-Potassium Pump
Pumps 3 sodium ions out of the cell and 2 potassium ions into the cell

42. PROTON PUMP
Moves
Protons
across
membrane
= ___ ions H+

43. PROTON PUMP ACTIVE ATP low high Protein pumps ___________ transport
(requires energy from ______)
Can move molecules from _____ concentration to ________
Special just for H+ ions
Uses integral ________________ to move molecules
Examples:
Lysosomes need acidic conditions for digestion
Photosynthesis/Respiration
ATP
low
high
Protein pumps

44. Vesicles
Many substances are too large to be transported by carrier proteins
Moved across the cell membrane by vesicles

45. Vesicles Endocytosis Movement of a substance into a cell by a vesicle
Exocytosis
Movement of substances by a vesicle to the outside of a cell

46. 2 KINDS of ENDOCYTOSIS for taking substances into cell
If taking in:
fluid or small molecules =_________________
large particles or whole cells =______________
PINOCYTOSIS
PHAGOCYTOSIS

47. PHAGOCYTOSIS
White blood cell
germs
___________ destroying _______

48. WHITE BLOOD CELL ENGULFING BACTERIA (Phagocytosis)

50. GOLGI BODIES USE EXOCYTOSIS

51. Kinds of ________ Transport
PASSIVE
__________________________________
___________________________________
_______________________________
Diffusion
Facilitated Diffusion
Carriers
Channels

52. Kinds of ________Transport
ACTIVE
________________________________________
__________________________________
________________________________
___________________________________
PUMPS
Sodium-Potassium
Proton
Vesicles
Endocytosis
Exocytosis

53. Review Video

54. Act It Out Passive Transport Active Transport Diffusion
Facilitated Diffusion: Ion Channels
Osmosis
Active Transport
Carrier Proteins/Protein Pumps (Na+/K+)
Vesicles