Cell TransportBLOCK Day: notes & Lab set up

Bellwork1. What is concentration? (NOT the kind where

you’re thinking really hard…)

2. Why is the orange juice you mix with water called “concentrate”?

3. Draw a picture showing the difference between the molecules in a LOW concentration solution vs a HIGH concentration solution

4. What is the difference between being passive and being active?

Cell Membrane Notes (in notebook)

• Copy down only most important things from each slide.

ON ODD PAGES INFO

3 drawings/diagrams

1 memory strategy

3 ?

summary

On Slates: name that membrane part (1-5)

2

3

4

1

Which side is the inside of the cell and which is the outside?

phospholipid5

• Semi-permeable• Solute• Solvent• Solution• Simple Diffusion• Concentration Gradient• Osmosis• Golden Rule of Osmosis

MYON – Diffusion & Osmosis Hypotonic Isotonic Hypertonic

Certain molecules can pass through and others are prevented.

Which part of the cell is semi-permeable?

Look around the room, can you name some things that are permeable and not permeable?

Being Semi-permeableSelective Permeability

Small molecules, such as O2 & CO2, can enter and leave the cell freely.

Large molecules such as proteins and carbs can’t.

Several processes are involved in moving materials across the membrane.

THINK: Which is passive and which is ‘active’?

Why is permeability important?

• SOLUTION• Solute• Solvent

• What are examples of each?

What do these key terms mean?

Solute

Solvent

Solution

Concentration

• Concentration: How close together molecules are in a solution; the amount of solute in a particular amount of solvent

• Which beaker has a higher concentration of food coloring?

Passive Transport• A concentration gradient is a

measurement of how the concentration of something changes from one place to another.

Passive Transport

• No energy required • Solutes are moved down the

concentration gradient:–Osmosis–Diffusion–Facilitated diffusion

Passive Transport• Osmosis- the

movement of water across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration

Hear Ye! Hear Ye! This is the Golden Rule of Osmosis:

The water follows the

solute!

• Why? You ask…– If the solute could spread out, it would.

( The Laws of Physics DEMAND it )– But when a semi-permeable membrane

stops them, there is only one thing that can move

– What is that?

The water follows the solute!

The Solvent• Which in the case of almost every single

biological situation is going to be our good friend…

WATER

The WATER will move to make the spaces between the solute even out.

This might mean the cell shrinks or swells up.

The water doesn’t care what the effect is on the cell because in

OSMOSIS…

The water follows the

solute!

BELLWORK:Explain & diagram what is happening when you drop a

plant cell into distilled water, and into salt solution. Label (solute and solvent) and water movement using an

arrow.

Passive Transport

• Simple Diffusion- movement of molecules (a solute) from an area of high concentration to an area of low concentration

Simple Diffusion- movement of molecules (a solute) from an area of high concentration to an area of low concentration

But wait, what’s a solute?

Solute(Kool-Aid powder)

Solvent (water)

Solution (Kool-Aid)

+ =

Solute: a substance that is dissolved in something else (the solvent).

Simple Diffusion

“Molecules” of Kool-Aid

Small dish of water

What will happen to the “molecules” of Kool-Aid?

They will diffuse!

Slate Work1. Draw where the solute (Kool-Aid

molecules) will be in 10 hours.

2. Write out the word for this process.

3. Think to yourself: did this happen all at once? What was the process?

Simple Diffusion

Concentration Gradient:difference in

concentration of a solute across a region

How would you describe this concentration gradient?

Putting it all together so far…Solutes diffuse along a concentration gradient from an area of high concentration to an area of low concentration.

Which way will the solute

diffuse?

Too much stirring.

For this to happen is stirring required?

What does that say about diffusion and the use of energy?

Diffusion…it just happens.

With your partner…

• Partner #1 – explain Osmosis and how is works!

• Partner #2 – explain simple diffusion and how it works!

Dialysis Tubing

• Is also IMPERMEABLE to sucrose…• Which is good, because I made a bunch of

sucrose solutions of different concentrations, and I can’t remember which is which.

Dialysis Lab – Your Job• Objective: To determine which of the

unknown solutions is High, Medium and Low concentration.

• Purpose: To observe the process of osmosis first hand and to use this process to understand how dialysis works.

Materials• 3 Unknown colored solutions (High, Med and

Low Concentration)• Water (150 mL)• 3 beakers*• 3 pieces of dialysis tubing*• 3 pipettes• Scissors• Scale• Paper towel

• PROCEDURES: Watch demo, and write down procedures

• Lab Title: Osmosis Lab (+ catchy title)• Problem/Question: Does ______________ of

_________ in the bag affect the final ________ of the bag in ___ after in soaks in water.

• Hypoth: • if _________________ (color solution) has

(highest/lowest solute concentration) relative to the

• Then _________________ • As measured by __________

Data table: Mass of dialysis tubes in grams

COLOR INITIAL FINAL Difference High/Low/Med

Red

Blue

Yellow

Diagram:Draw all 3 set ups at the start of the experiment and 15 minutes later.-Include particulate drawings showing H20, and sucrose molecules.-Label the solute and the solvent. -Use arrows to show the flow of water

• Materials:

• Procedures:

• Data Table:

• Qual. Observations

• Graph: line/bar• Conclusion