1. Examples of: Passive & Active Transport
Warm Up: Describe the diagram below by using the following words (this should be REVIIIIEEEWWWW)
Solution 4. doing dissolving
2. Solvent 5. being dissolved
3. Solute

2. Critical Question
Explain what happens to the cells in a salt water fish if placed in fresh water.
Then grab the following diagram for labeling.
Water =
Outside the cell
Salt =
Inside the cell
Plasma membrane

3. Passive Transport: Osmosis
Brainstorm!!
Which direction do you think the water will move in diagram 1?
What do you think will happen to the yellow circle’s size?
Osmosis diffusion of water from
HIGH concentration of H20 (low solute) to
LOW concentration of H20 (high solute)
Label the Circles (1 & 2) – as either high concentration water / low solute or low concentration water / high solute

4. Types of Solutions Hypertonic Hypotonic
When water leaves the cell because the Solution has a:
High Concentration solute
Less water
Cell shrinks
When water enters the cell because the Solution has a:
Low Concentration solute
More water
Cell swells (think hypO)

5. Equal amount of molecules leaving and entering the cell
Keeping water balance
Cell survival depends on balancing water uptake & water loss
Equal amount of molecules leaving and entering the cell
Isotonic
Hypotonic
Hypertonic

6. Keeping right amount of water in cell1
Keeping right amount of water in cell
Hypotonic
a cell in fresh water
high concentration (more) of water around cell
cell gains water
example: Paramecium
problem: cells gain water, swell & can burst
water continually enters Paramecium cell
solution: contractile vacuole
pumps water out of cell
KABOOM!
freshwater
No problem, here

7. Keeping right amount of water in cell2
Keeping right amount of water in cell
Hypertonic
a cell in salt water
Less / low concentration of water around cell
cell loses water
example: shellfish
problem: cell loses water
in plants: plasmolysis
in animals: shrinking cell
solution: take up water
I’m shrinking, I’m shrinking!
saltwater
I will survive!

8. Keeping right amount of water in cell3
Keeping right amount of water in cell
Isotonic
no difference in concentration of water between cell & environment
cell in equilibrium
example: blood
problem: none
water flows across membrane equally, in both directions
volume of cell doesn’t change
That’s better!
balanced
I could be better…

9. Active Transport : Endocytosis
Endocytosis: taking bulky material into a cell
Uses energy
Cell membrane folds in around food particle creating a vacuole (sac)
“cell eating”
This is how white blood cells eat bacteria!

10. Active Transport : Exocytosis
Exocytosis: Forces material out of cell in bulk
membrane surrounding the material fuses with cell membrane
requires energy - Cell changes shape
EX: Hormones or wastes released from cell
Endocytosis & Exocytosis animations

11. Critical Question
Explain what happens to the cells in a salt water fish if placed in fresh water.

12. Appling
A young woman decides to go for a hike in Yellowstone National Park on a summer day.
She brings:
a water bottle,
protein bar,
hat,
some sunscreen and
bear repellant.
Before her hike, she has a very good breakfast including eggs, oatmeal, fruit, and orange juice.
At the beginning the 9 am hike, the day is cool and she’s wearing shorts, a t-shirt,
and a light jacket.
By noon, she has hiked 5 miles, it is 95 degrees, and very sunny.
Describe what cellular processes are occurring to the woman during the day.
What occurs inside her body after eating breakfast?
What occurs inside her body as she starts her hike?
What occurs inside her body as the day warms, and how might she respond to this?
At noon, what may be occurring at a cellular and body level, and why?
Within your group, answer the questions, brainstorm, and create a list of what may be occurring at both the cellular & body level for this woman.
Create your list in your Engage Student Handout. Once your group has completed your list, raise your hand.