1. Transport Processes Across the Cell Membrane
Review: The Cell Membrane
made of?
Phosopholipids and proteins
two word definition?
Selectively permeable
video of cell membrane complexity
Gate Keeper Function
Four processes
diffusion
facilitated diffusion
osmosis
active transport

2. Diffusion
What is diffusion?
Lets go to the video tape!!!!!
Definition:
Random movement of molecules from an area of greater concentration to an area of lesser concentration
Two-word definition:
random walk
Diffusion animation:
Diffusion animation II:

3. concentration gradient
Diffusion System A B
NaCl
Pure H2O
concentration gradient
SPM

4. A B Osmosis System SPM NaCl Pure H2O
The concentration gradient according to water will slope in which direction?
Where is the higher concentration of water?

5. Osmosis
Definition:
The random movement of water from a area of higher concentration to an area of lesser concentration across an SPM
Connected Concepts
Solute:
material dissolved a solution
Solvent:
solution in which materials are dissolved in

6. Osmosis Connected Concepts Which solution has more solutes?
Comparative Terms
Hyper:
more solutes
Hypo:
less solutes
Iso:
equal amounts of solutes

7. A B Osmosis System SPM NaCl Which way will water move?` Pure H2O
salt
Pure H2O
Which way will salt move?
Which side is the hypertonic and which is the hypotonic?
water
Hypertonic Solution
Hypotonic Solution
more solutes
less solutes

8. Osmosis System
How do one celled organisms survive their hypotonic environments?
Adaptation for survival
Contractile vacuole saves the day!

9. Osmosis System
What happens to cells when they are put into a hypertonic solution?
Check out the video man!
Phenomenon is called:
Plasmolysis
water
destruction
a. The cytoplasm diffuses out of the cell shrinking the volume of cytoplasm
b. Plant cells lose turgor pressure which the hydrostatic pressure created by water pressing up against the cell wall

10. Let’s Review
Transport processes
Diffusion
Osmosis
Passive: no energy required
How do molecules in lower concentration outside the cell get into the cell?
Need some kind of energized system

11. Active Transport System
SPM A B
Outside cell
Inside cell
Which way does the concentration gradient slope for salt (yellow dots)?
Need energy: ATP

12. PROTEINS Other Transport Processes 1. endocytosis “inside the cell”
a. Phagocytosis or cell eating
White blood cells like neutrophils and monocytes (watch them in action)
b. pinocytosis or cell drinking
Cell “drinks” in dissolved materials by trapping tiny droplets in a fold of membrane
The opposite of endo would be?
1. exocytosis
“outside the cell”
a. Secretion of material outside the cell like wastes and cell-by products, like different?
PROTEINS