Exchange with the Exchange with the EnvironmentEnvironmentBell Work:1/4/13Bell Work:1/4/13

What would happen to a factory if its What would happen to a factory if its power were shut off or its supply of raw power were shut off or its supply of raw materials never arrived?materials never arrived?

What would happen if the factory couldn’t What would happen if the factory couldn’t get rid of its garbage?get rid of its garbage?

Look at page 78!Look at page 78!

ObjectivesObjectives Explain how materials move through Explain how materials move through

simple diffusion. (SPI 0707.1.5)simple diffusion. (SPI 0707.1.5) Diffusion/Osmosis Demo, Lab, & NotesDiffusion/Osmosis Demo, Lab, & Notes

Table of ContentsTable of Contents: : 62. Diffusion and Osmosis Notes62. Diffusion and Osmosis Notes

Challenge Question? Challenge Question? What cell organelle allows things to move What cell organelle allows things to move

in and out of the cell? in and out of the cell?

What things are allowed in and out of the What things are allowed in and out of the cell? cell?

Discuss the questions with your Elbow Discuss the questions with your Elbow Partner. Partner.

Blowing BubblesBlowing Bubbles• Soap bubbles have

properties, such as flexibility, that are similar to cell membranes.

• Components of soap film and of cell membranes move around freely because they are made of proteins and lipids (fats).

What is Diffusion?What is Diffusion? The movement of particles from regions The movement of particles from regions

or areas of _________ concentration or areas of _________ concentration (crowded) to areas of ________ (crowded) to areas of ________ concentration (less crowded) is called concentration (less crowded) is called ____________. ____________.

Look at Figure 1 on pg. 78!Look at Figure 1 on pg. 78! The dye moved from an area of high The dye moved from an area of high

concentration and spread to the area of concentration and spread to the area of low concentration.low concentration.

Ex: when oxygen diffuses into the cell Ex: when oxygen diffuses into the cell and carbon dioxide diffuses out.and carbon dioxide diffuses out.

highlow

diffusion

Diffusion of WaterDiffusion of Water Diffusion also happens with and between Diffusion also happens with and between

living cells.living cells. The cells of organisms are surrounded by The cells of organisms are surrounded by

and filled with fluids that are made mostly of and filled with fluids that are made mostly of ________.________.

The diffusion of water through a The diffusion of water through a _____________ (partially allows things _____________ (partially allows things through) membrane is so important that it through) membrane is so important that it has been given a special name- has been given a special name- __________.__________.

Look at Figure 2 on pg. 79!Look at Figure 2 on pg. 79!

water

osmosis

semipermeable

Question...Elbow PartnerQuestion...Elbow Partner In diffusion and osmosis, why do the In diffusion and osmosis, why do the

particles move from areas that are particles move from areas that are more crowded to areas that are less more crowded to areas that are less crowded?crowded? For a cell to survive, the amount of For a cell to survive, the amount of

molecules need to be the same on both molecules need to be the same on both sides of the cell membrane. If the cell sides of the cell membrane. If the cell does not pump out all of its extras to even does not pump out all of its extras to even things out, this could be very bad. The cell things out, this could be very bad. The cell can swell up and explode. can swell up and explode.

Listen to this…

Moving Small ParticlesMoving Small Particles In a cell, the movement of particles across a cell membrane In a cell, the movement of particles across a cell membrane

_________ the use of energy by the cell is called _________ the use of energy by the cell is called __________ ___________.__________ ___________.

During passive transport, particles move from an area of During passive transport, particles move from an area of _______ concentration to an area of _______ _______ concentration to an area of _______ concentration.concentration.

Examples:__________ & __________Examples:__________ & __________ A process of transporting particles that requires the cell to A process of transporting particles that requires the cell to

use energy is called ________ ____________. use energy is called ________ ____________. Active transport usually involves the movement of particles Active transport usually involves the movement of particles

from an area of _______ concentration to an area of from an area of _______ concentration to an area of _______ concentration._______ concentration. This happens a lot in neurons. The membrane proteins This happens a lot in neurons. The membrane proteins

are constantly pumping ions (atoms or molecules that are constantly pumping ions (atoms or molecules that have a + or – electrical charge) in and out to get the have a + or – electrical charge) in and out to get the membrane of the neuron ready to transmit electrical membrane of the neuron ready to transmit electrical impulses. impulses.

withoutpassive transport

high low

Diffusion Osmosis

active transport

lowhigh

Moving Large ParticlesMoving Large Particles The active transport by which a cell surrounds a large The active transport by which a cell surrounds a large

particle, such as a large _________, and encloses the particle, such as a large _________, and encloses the particle in a vesicle to bring the particle into the cell is particle in a vesicle to bring the particle into the cell is called _______________.called _______________.

Vesicles are _____ formed from pieces of cell Vesicles are _____ formed from pieces of cell membrane.membrane. Ex: when iron diffuses into the cell using active Ex: when iron diffuses into the cell using active

transport because the iron molecules are too large.transport because the iron molecules are too large. When large particles, such as ________, leave the cell, When large particles, such as ________, leave the cell,

the cell uses an active transport called the cell uses an active transport called ______________. ______________.

During exocytosis, a vesicle forms around the large During exocytosis, a vesicle forms around the large particle, carries the particle to the cell membrane, fuses particle, carries the particle to the cell membrane, fuses with the cell membrane, and releases the particle with the cell membrane, and releases the particle outside of the cell. outside of the cell.

protein

endocytosissacs

wastes

exocytosis

What do you know?What do you know?

Describe how each of the following materials Describe how each of the following materials would get through the cell membrane and would get through the cell membrane and into a cell:into a cell:

1.1. Pure waterPure water2.2. Sugar entering a cell that already contains a Sugar entering a cell that already contains a

high concentration of particleshigh concentration of particles3.3. Sugar entering a cell that has a low Sugar entering a cell that has a low

concentration of particlesconcentration of particles4.4. A proteinA protein

(osmosis)

(active transport)

(passive transport)(endocytosis)

Diffusion LabDiffusion Lab1.1. Fill beaker halfway with water. Teacher will add 20 Fill beaker halfway with water. Teacher will add 20

drops of iodine to the water.drops of iodine to the water.2.2. CAREFULLYCAREFULLY place two heaping spoonfuls of place two heaping spoonfuls of

cornstarch into a plastic bag.cornstarch into a plastic bag.3.3. CAREFULLYCAREFULLY add 25 ml of water in the bag of add 25 ml of water in the bag of

cornstarch, keeping solution in the corner of the bag. cornstarch, keeping solution in the corner of the bag. Seal the bag. Move the corner of the bag between Seal the bag. Move the corner of the bag between your fingers to mix the cornstarch and water together. your fingers to mix the cornstarch and water together.

4.4. Place the bag in the beaker and wait. Place the bag in the beaker and wait. 5.5. Check the bag and record your observations after 5, Check the bag and record your observations after 5,

10, and 15 minutes. 10, and 15 minutes. 6.6. While waiting, fill out the lab paper, both front and While waiting, fill out the lab paper, both front and

back. If you don’t finish, it will be homework. back. If you don’t finish, it will be homework.

Diffusion Lab Questions1. The plastic bag is semipermeable to

which substance?2. Why did the iodine enter the bag?3. Why didn’t the starch enter the

beaker?4. How is the plastic bag like the cell

membrane?5. What is the definition of the word

“diffusion”?