Do Now

• What is osmosis?

• What happened when we put our gummi bears into water?

• WHY did this happen?

Objectives• To understand what happens during

osmosis in regards to osmotic pressure.

• To compare and contrast hypertonic, hypotonic, and isotonic solutions.

• To explain different real life applications of these solutions.

Osmotic Pressure

• What is osmosis?

• Whichever has MORE water (either the solution or the solution inside the cell) is going to be the one to have a higher osmotic pressure and the water will flow in the direction of lower osmotic pressure.

“Tonicity”

• The measure of osmotic pressure

• There are 3 types of solutions in regards to tonicity – Isotonic– Hypertonic – Hypotonic

Quick Refresher!

• What is a solution?

• Solute vs. solvent?

• Example?-

Isotonic Solutions• Same amount of solute outside the

membrane as there is inside.

• Effect: NOTHING

Blood CellPlant Cell

11,397x

Hypertonic Solutions

• Solution contains MORE SOLUTE than the cell, water flows out of the cell.

• Effect: cell shrinks/shrivels

“Plasmolysis”“Crenates”

Hypotonic Solutions• Solution contains LESS SOLUTE than the

cell, water flows into the cell.

• Effect: cell swells or bursts! /

• (remember the grocery store misters?)

Animations

• http://www.biologyjunction.com/tonicity%20animations.htm

High or low Solute?

Cell in ________ Solution

Cell in ________ Solution

Cell in ________ Solution

H2

OH2

O

H2

OH2

OH2

OH2

O

Real Life Application

• Turn to the person sitting next to you. In the next few slides you will see real life scenarios using the 3 types of solutions we have discussed. For each scenario you and your partner should determine what type of solution is being described as well as what will happen.

Scenario 1

• What type of solution is the freshwater?

• What is going to happen to the cells of the fish?

A salt water fish is put into a freshwater aquarium.

Scenario 2

• What type of solution is in the IV?

• What is going to happen to the cells of the human?

A patient is given an IV, which contains the perfect balance of glucose

Scenario 3

• What type of solution is this salt?

• What is going to happen to the cells of the slug? (don’t do this to the poor slugs )

Your garden is infested with slugs so you go around pouring salt on them

Practice

• By yourself or with a partner (anyone), work on the diffusion problems.

• First try to do this by yourself, then verify your answers with a partner. Try to help each other. If you are confused, raise your hand and I will come help you!!

• If you finish early, try to answer the “Think about it” questions on my desk! If you don’t finish, please finish it for homework.

3-2-1 Exit Slip

• On a SEPARATE sheet of paper…

• List 3 things you learned today• List 2 things you are confused

about• List 1 thing you found interesting