Diffusion Catalyst: What is the function of the cell membrane? It was hot last night, so Teyhones turned on the air conditioning in his house. But.

Diffusion

Catalyst: What is the function of the cell

membrane? It was hot last night, so Teyhones

turned on the air conditioning in his house. But his sister, Perrinika, accidentally left the front door open. What happened to the temperature in Teyhones’ house, and why? Be specific!

Write in complete sentences!

Don’t talk during the Catalyst!

Objectives

By the end of the period, all SWBAT…Predict the movement of molecules using diffusion

Definitions

Solution = a mixture of solute and solvent

Concentration = measurement of how much solute there is in the solvent High concentration: lots of solute, compared to

solvent Low concentration: little solute, compared to solvent

liquid

stufffinal product

Can you give me some examples?

Fill in the blanks: in _______________,

the _______________ is mixed into the

_______________.

SOLUTE

SOLVENT

SOLUTION

HIGH LOW

SolutesWhat do you think would happen if we opened up a path between these two boxes?

Concentration

75% Solute

5% Solute

Diffusion

Key Point #1: Diffusion is the net movement of molecules from an area of high concentration to an area of low concentration Molecules are always moving They bump into each other This knocks molecules from the area

of high concentration into the area of low concentration

Diffusion

75% Solute

25% Solute

65% Solute

35% Solute

50% Solute

50% Solute

Diffusion

Key Point #2: Diffusion continues until there is equilibrium Equilibrium = The point at which two connected solutions have equal concentrations

Diffusion

Diffusion moves toward equilibrium75% Solute

25% Solute

65% Solute

35% Solute

50% Solute

50% Solute

Demonstration

In notes answer these two questions I have a bottle of ink and a beaker of tap

water. Which has the higher concentration of ink? Predict what will happen if I put a couple of

drops of ink in the beaker of the water.

We will check in on this later on today…

Solutes move even when concentration is equal

“Net movement” of molecules

50% Solute

50% Solute

Demo!

LYSOL

Molecules move from HIGH concentration to LOW concentration

All this is great, but…

But what happens when you can’t just move from one area to another Like there might be something that controls what goes in and out…

Like a cell membrane…

Cell Membranes

Key Point #3: Cell membranes are selectively permeable Selectively permeable = only let

certain things pass through

Selectively Permeable Cell Membrane Cell membranes control what enters

and what leaves the cell Small things diffuse in, because they

can fit between the gaps in the cell membrane

Big things are kept out, because they cannot

-+

+-

The diagram below shows a cells, surrounded by a semi-permeable membrane, in the bloodstream.

How will the solute move, according to diffusion?

Example

10% Sugar Solution

80% Sugar Solution

Guided Practice

Provide your own example of a solution. Then, state what the solute and solvent in it are.

DO NOT USE HOT CHOCOLATE, OR ANY OTHER EXAMPLE WE HAVE DISCUSSED IN CLASS TODAY.

Guided Practice

The diagram below shows two cells, separated by a semi-permeable membrane.

How will the solute move, according to diffusion?

The diagram below shows two cells, separated by a semi-permeable membrane.

How will the solute move, according to diffusion?

Guided Practice

72% Sugar Solution

34% Sugar Solution

The diagram below shows two cells, separated by a semi-permeable membrane.

How will the solute move, according to diffusion?

Guided Practice

55% solute

85% solute

The diagram below shows two cells, separated by a semi-permeable membrane.

Draw what this situation will look like after diffusion has FINISHED.

Guided Practice

38% solute

41% solute

Guided Practice

“Diffusion causes solutions to move toward equilibrium.”

Describe what this means in your own words, and in complete sentences.

Exit Question

The diagram below shows two cells, separated by a semi-permeable membrane.

How will the solute move, according to diffusion?

When will net movement of the solute stop? Use the vocabulary we learned today!

Write in complete sentences!

Don’t talk during the Exit Question!