Hmmmmm…. If you were stranded in the middle of the ocean, would you drink the salt water?
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Transcript of Hmmmmm…. If you were stranded in the middle of the ocean, would you drink the salt water?
Hmmmmm…. If you were stranded in the middle of the
ocean, would you drink the salt water?
Salty Potatoes!1. Grab 3 slices of potatoes and 2 beakers.2. Pour 100mL of water into EACH beaker.3. Pour 2 spoonfuls of salt into ONE beaker4. Place one potato slice into each beaker,
leave one potato slice on a paper towel. 5. In your journal, predict what will happen to
the size and texture of the potato at the end of class.
The Cell Membrane & Transportation of Molecules
Objectives:1.To describe the role and structure of the cell membrane. 2.Predict how molecules will enter and leave the cell.
About Cell Membranes
1. All cells have a cell membrane
2.Functions:
a.Controls what enters and exits the cell to maintain an internal balance called homeostasis
b.Provides protection and support for the cell
Picture of a real cell membrane.
About Cell Membranes (continued)
3. Structure of cell membrane
Lipid Bilayer -2 layers of phospholipidsa.Phosphate headb.Fatty acid tailsc.Proteins embedded in
membrane
Phospholipid
Lipid Bilayer
About Cell Membranes (continued)
4. Selectively permeable: Allows some molecules in and keeps other molecules out
Pores
Outside of cell
Inside of cell (cytoplasm)
Lipid Bilayer
Proteins
Transport Protein Phospholipids
Sugar chains
Structure of the Cell Membrane
Go to Section:
Membrane movement animation
Polar heads love water
Non-polar tails hide from water.
Fluid Mosaic Model of the
cell membrane
Hmmmmm…. If you were stranded in the middle of the
ocean, would you drink the salt water?
Reflection In your journals make a chart and fill in:
O W LThis is what I OBSERVED
That is what I WONDER
This is what I LEARNED
Hmmmmm…. If you were stranded in the middle of the
ocean, would you drink the salt water?
Video www.brainpop.com “Passive Transport” “Gills”
Passive vs Active Transport Objectives:
1. Identify the characteristics of Passive and Active Transport that the cell membrane uses.
2.Set up a lab and observe an example of passive transport.
Passive Transport cell uses no energy molecules move randomly Molecules spread out from an area of
high concentration to an area of low concentration.
HighLow
high
low
Weeee!!!
Active Transport
•cell uses energy
•actively moves molecules to where they are needed
•Movement from an area of low concentration to an area of high concentration
•Low High high
low
This is gonna
be hard work!!
Animations of Active Transport & Passive Transport
Types of Active Transport
Proteins embedded in the bilipid layer move molecules from a LOW to HIGH concentration.
Sodium Potassium Pumps
Passive Transport:
1. Diffusion: random movement
of particles from high to low
Diffusion continues until all molecules are evenly spaced (equilibrium is reached)-Note: molecules will still move around but stay spread out.
http://bio.winona.edu/berg/Free.htm
Simple Diffusion
Animation
Diffusion & Dialysis Tube Lab It is very difficult to measure or see diffusion actually
occurring in cells because of the small size of most cells. Dialysis tubing is a manmade semi-permeable membrane that is used to treat people who have kidney failure. It acts similarly to a real plasma membrane. The driving force behind dialysis is the concentration difference between two solutions on opposite sides of the membrane. Which molecule will diffuse across the semi-permeable
membrane? Iodine or Starch?
OsmosisObjectives:1.Collect results from yesterday’s lab and
conclude whether iodine or starch diffused through the membrane.
2.Explain the process of osmosis and describe the three ways it can affect the size of a cell.
Diffusion & Dialysis Tube Lab Results
2. Osmosis: diffusion of water
Water moves from high to low concentrations
•Water moves freely through pores.
•Solute (green) too large to move across.
Osmosis animation
Hypotonic Solution
Hypotonic: There is MORE water in the solution than inside the cell.
Result: Water moves from the solution to inside the cell. Animals cells swell and burst, plants cell swell up and do not burst.
• Osmosis Animations for
isotonic, hypertonic, and
hypotonic solutions
Hypertonic Solution
Hypertonic: There is LESS water in the solution than inside the cell.
Result: Water moves out of the cell and the cell shrinks.
• Osmosis Animations for
isotonic, hypertonic, and
hypotonic solutions
shrinks
Isotonic Solution
Isotonic: The concentration of water is equal inside and outside the cell. (Equilibrium homeostasis)
Result: Water moves equally in both directions and the cell remains same size!
• Osmosis Animations for
isotonic, hypertonic, and
hypotonic solutions
Osmosis in Red Onionhttp://www.teachertube.com/viewVideo.php?video_id=135394
Hypertonic or Hypotonic?
What type of solution are these cells in?
A CB
Hypertonic
Isotonic
Hypotonic