1. WAYS MOLECULES MOVE Chapter 7-3

2. See a video clip about
DIFFUSION-7A

3. Diffusion

4. FROM A LOT to NOT Molecules move _______“where there’s _______”
Animatioin from:
Molecules move
_______“where there’s _______”
____“where there’s _______”
FROM
A LOT to
NOT

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

6. DIFFUSION across a SPACE
Molecules move automatically _______ the concentration gradient _______ an area of _______ concentration ____ an area of ________ concentration
EXAMPLES
DOWN
from
Higher to
Lower
Blue dye in beaker demo,
Someone making popcorn/grilling out
Strong perfume,
Bad smell in room

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

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

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

10. DIFFUSION across a membrane
DIFFERENCE
Happens anytime there is a __________ in _____________ on one side of the membrane compared to the other
concentration
See diffusion animation

11. CELL EXAMPLE:
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)

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

13. PROBLEM for Cells? Cell membranes are SELECTIVELY PERMEABLE
Video from:
PROBLEM for Cells? Cell membranes are SELECTIVELY PERMEABLE
See a movie

14. What if cell needs to move a molecule _________ the CONCENTRATION GRADIENT? _______________
AGAINST
(LOWER  HIGHER)
Cell example:
Want to put MORE glucose
into mitochondria when there is
already glucose in there
Image from:

15. 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

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

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

18. ________________ and ___________ help molecules to cross cell membranes
Membrane proteins
vesicles
Animations from:

19. OSMOSIS polar ________ proteins allow ________
_________ molecules to get past
the __________ middle of cell
membrane.
Aquaporin
WATER
hydrophobic

20. OSMOSIS The movement of water molecules
across a cell membrane is called
______________
OSMOSIS

21. DIFFUSION DOWN HIGHER to LOWER OXYGEN Carbon dioxide
DIFFUSION
No energy required
Moves _______ concentration gradient
from ___________________
Works for any molecules that can pass through the membrane
Example of molecules that move this way in cells:
________ & ____________
DOWN
HIGHER to LOWER
OXYGEN Carbon dioxide

22. OSMOSIS No energy required Moves ________ concentration gradient
from ________________________
__________________ help molecules get across membrane
EX: __________ help _______ move across the cell membrane
DOWN
HIGHER to LOWER
Membrane proteins
Aquaporins
WATER

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

24. 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

25. Use new vocab to make Koolaid
Koolaid powder
sugar
Solutes = ______________& __________
Solvent = ____________
Koolaid drink = ______________
Water
solution

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

27. See a video clip about
OSMOSIS -7B

28. Animation

29. What will happen to an animal cell placed in different solutions?
Solute concentration
Greater outside
than inside
Lower outside
than inside
Equal outside
and inside
HYPERTONIC
HYPOTONIC
ISOTONIC
What will happen to an animal cell
placed in different solutions?

30. Cells try to “maintain stable internal conditions =
Remember:
Cells try to “maintain stable internal conditions =
____________________
HOMEOSTASIS
So an animal cell in
ISOTONIC conditions
stays same size
Water entering = water leaving
Video
Choose Blood Isotonic link

31. If cells can’t maintain “stable internal conditions” . . .
damage can result and cells can die.

32. OSMOSIS swell and possibly burst Video LESS THAN
Animation from:
OSMOSIS
Video
Choose Blood
Hypotonic link
HYPOTONIC: Concentration outside cell is ________________ inside the cell More water enters than leaves cell so cell will ___________________
LESS THAN
swell and possibly burst

33. OSMOSIS shrinks GREATER THAN Video
Animation from:
OSMOSIS
HYPERTONIC: Concentration outside cell is ____________________ inside cell
More water leaves cell than enters so cell ____________
GREATER THAN
shrinks
Choose Blood
Hypertonic link
Video

34. Animal cells _________ __________ = CYTOLYSIS = CRENATION
_________ __________
= CYTOLYSIS
= CRENATION

35. Plant cells _____ keeps ___________ = PLASMOLYSIS CELL WALL
Plant cells
_____ keeps ___________
plant cells from bursting
= PLASMOLYSIS
CELL WALL

36. VACUOLES store WATER OSMOTIC PRESSURE _____________________________ =
OSMOTIC PRESSURE
_____________________________ =
Pressure exerted by the movement of water during osmosis

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

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

39. SO WHAT? If an organism can’t maintain homeostasis, it will die.
SO Salt water fish urinate rarely and actively pump ions out through their gills
Freshwater fish urinate constantly and actively pump ions in through their gills

40. SOUTH DAKOTA SCIENCE STANDARDS
LIFE SCIENCE
Indicator 1: Understand the fundamental structures, functions, classifications, and mechanisms found in living things.
9-12.L Students are able to relate cellular functions and processes to specialized structures within cells.
Transport

41. Core High School Life Science Performance Descriptors
High school students performing at the
ADVANCED level:
predict how homeostasis is maintained within living systems;
predict the function of a given structure;
PROFICIENT level:
describe the relationship between structure and function;
predict how life systems respond to changes in the environment;
BASIC level
recognize that different structures perform different functions;
define homeostasis;