Exchange with the Exchange with the EnvironmentEnvironmentBell Work: 1/10/14Bell Work: 1/10/14

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 Lab & NotesDiffusion/Osmosis Lab & Notes

Teacher DemoTeacher Demo• 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).

• The Video…• A bubble is full of air. It floats on the carbon dioxide layer

just like a helium balloon floating in the air. You might expect that the air in the bubble would cool and contract near the dry ice, but the bubble actually expands slightly. The soapy wall of the bubble allows carbon dioxide to pass through but does not allow air molecules inside the bubble to get out. Why?

46. Diffusion Lab46. Diffusion 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 50 ml of water in the bag of add 50 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, discuss and describe the science While waiting, discuss and describe the science terms in your own words with your group.terms in your own words with your group.

Diffusion Lab Questions

1. 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”?

Bell Work: 1/13/14Make sure the following questions are answered on your

lab page in your scientist notebook.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”?

After you answer the above questions, complete the following questions on your bell work sheet:

• Pg. 81 #7; use pg. 80 to help you answer the questions.

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 NotesDiffusion/Osmosis Notes

Let’s connect the dots…Let’s connect the dots… Cell membraneCell membrane Diffusion labDiffusion lab

47. Diffusion & Osmosis Notes47. Diffusion & Osmosis NotesWhat 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. Why?low concentration. Why?

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

EquilibriumEquilibrium• Sugar molecules, initially Sugar molecules, initially

in a high concentration in a high concentration at the bottom of a at the bottom of a beaker, will move about beaker, will move about randomly through randomly through diffusion and eventually diffusion and eventually reach equilibrium.reach equilibrium.

• At equilibrium the sugar At equilibrium the sugar concentration will be the concentration will be the same throughout the same throughout the beaker.beaker.

• Diffusion occurs Diffusion occurs naturally because of the naturally because of the kinetic energy the kinetic energy the molecules possess.molecules possess.

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 does not pump out all of its extras to even things out, this could be very bad. even things out, this could be very bad. The cell can swell up and explode. The cell can swell up and explode.

Listen to this…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._______ concentration to an area of _______ 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 When large particles, such as ________, leave the

cell, the cell uses an active transport called cell, 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, particle, carries the particle to the cell membrane, fuses with the cell membrane, and releases the fuses with the cell membrane, and releases the particle outside of the cell. particle 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)