Exchange with the Environment Bell Work: 1/5/15  What would happen to a factory if its power were shut off or its supply of raw materials never arrived?  What would happen if the factory couldn’t get rid of its garbage?  Look at page 78!

Objectives  Explain how materials move through simple diffusion. (SPI )  Diffusion/Osmosis Lab & Notes

Teacher 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?

47. Diffusion Lab 1.Fill beaker halfway with water. Teacher will add 20 drops of iodine to the water. 2. CAREFULLY place two heaping spoonfuls of cornstarch into a plastic bag. 3.CAREFULLY add 50 ml of water in the bag of cornstarch, keeping solution in the corner of the bag. Seal the bag. Move the corner of the bag between your fingers to mix the cornstarch and water together. 4.Place the bag in the beaker and wait. 5.Check the bag and record your observations after 5, 10, and 15 minutes. 6.While waiting, answer the following questions in your scientist notebook.

Diffusion Lab Questions 1. 1.The plastic bag is semipermeable to which substance? 2. 2.Why did the iodine enter the bag? 3. 3.Why didn’t the starch enter the beaker? 4. 4.How is the plastic bag like the cell membrane? 5. 5.What is the definition of the word “diffusion”?

48. Diffusion & Osmosis Notes What is Diffusion?  The movement of particles from regions or areas of _________ concentration (crowded) to areas of ________ concentration (less crowded) is called ____________.  Look at Figure 1 on pg. 78!  The dye moved from an area of high concentration and spread to the area of low concentration. Why?  Ex: when oxygen diffuses into the cell and carbon dioxide diffuses out. high low diffusion

Equilibrium Sugar molecules, initially in a high concentration at the bottom of a beaker, will move about randomly through diffusion and eventually reach equilibrium. Sugar molecules, initially in a high concentration at the bottom of a beaker, will move about randomly through diffusion and eventually reach equilibrium. At equilibrium the sugar concentration will be the same throughout the beaker. At equilibrium the sugar concentration will be the same throughout the beaker. Diffusion occurs naturally because of the kinetic energy the molecules possess. Diffusion occurs naturally because of the kinetic energy the molecules possess.

Diffusion of Water  Diffusion also happens with and between living cells.  The cells of organisms are surrounded by and filled with fluids that are made mostly of ________.  The diffusion of water through a _____________ (partially allows things through) membrane is so important that it has been given a special name- __________.  Look at Figure 2 on pg. 79! water osmosis semipermeable

Bell Work: 1/6/15 Make sure the following questions are answered on your lab page in your scientist notebook. 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”? 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.

Question...Elbow Partner  In diffusion and osmosis, why do the particles move from areas that are more crowded to areas that are less crowded?  For a cell to survive, the amount of molecules need to be the same on both sides of the cell membrane. If the cell does not pump out all of its extras to even things out, this could be very bad. The cell can swell up and explode.  Listen to this… Listen to this… Listen to this…

Bell Work: 1/14/14   Use the sheet in your group’s colored folder for bell work. Do not write on the sheet.   Write the question, letter, and draw the picture of the correct answer on your bell work sheet. Justify.

Objectives  Explain how materials move through simple diffusion. (SPI )  Diffusion/Osmosis Notes

Moving Small Particles  In a cell, the movement of particles across a cell membrane _________ the use of energy by the cell is called __________ ___________.  During passive transport, particles move from an area of _______ concentration to an area of _______ concentration.  Examples:__________ & __________  A process of transporting particles that requires the cell to use energy is called ________ ____________.  Active transport usually involves the movement of particles from an area of _______ concentration to an area of _______ concentration.  This happens a lot in neurons. The membrane proteins are constantly pumping ions (atoms or molecules that have a + or – electrical charge) in and out to get the membrane of the neuron ready to transmit electrical impulses. without passivetransport highlow Diffusion Osmosis activetransport low high =

Moving Large Particles  The active transport by which a cell surrounds a large particle, such as a large _________, and encloses the particle in a vesicle to bring the particle into the cell is called _______________.  Vesicles are _____ formed from pieces of cell membrane.  Ex: when iron diffuses into the cell using active transport because the iron molecules are too large.  When large particles, such as ________, leave the cell, the cell uses an active transport called ______________.  During exocytosis, a vesicle forms around the large particle, carries the particle to the cell membrane, fuses with the cell membrane, and releases the particle outside of the cell. protein endocytosis sacs wastes exocytosis

What do you know? Describe how each of the following materials would get through the cell membrane and into a cell: 1.Pure water 2.Sugar entering a cell that already contains a high concentration of particles 3.Sugar entering a cell that has a low concentration of particles 4.A protein (osmosis) (active transport) (passive transport) (endocytosis)

49. Osmosis & Diffusion of an Egg

CAN PLANTS THINK? Watch this…