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Warm Up (Silent)1/28
What two molecules make up the phospholipid bilayer?
The Cell Membrane
Hydrophobic
Hydrophilic
Hydrophilic
ALL cells are microscopic!
Cells never get as big as the Blob.
Cells can’ t be big because…….Surface area won’ tallow enough material to enter ( O2, water, food) to keep the cell interior alive.
Cell Membrane Questions
Answer the questions on the handout. Use your notes to help you answer the questions.
DRAW a portion of the cell membrane on a plain piece of paper. It should be NEAT, FREEHAND, LABELED, AND COLORED. Use the picture on page 78 of the blue book as a pattern
Getting through the Membrane
The Membrane is Selectively PermeableSelective = ChoosesPermeable = Passes through
The membrane chooses which molecules pass through
Concentration
Just like people, molecules don't like to be crowded.
Concentrated = Crowded
Diffusion - Spreading Out
Diffusion - molecules naturally move from high concentrated areas to low concentrated areas.
Equilibrium - when molecules are evenly spread out.
OsmosisWater molecules also doesn't like to be crowded. Osmosis - Movement of water from high concentration of water to a low concentration of water, across a cell membrane.
Osmosis Problems1. Elevator = 80% capacity of people 2nd Floor = 5% capacity of people
2. Beaker = 60% water, 40% salt Dialysis Tube = 20% water, 80% salt
3. Beaker = 10% water, 90% sugar Egg = 60% water, 40% other molecules
4. Beaker = 100% water Egg = 50% water, 50% sugar
Osmosis Problems1. Elevator = 80% capacity of people 2nd Floor = 5% capacity of peopleWill claustrophobic people move into or out of the elevator when it stops at the 2nd floor? 2. Beaker = 60% water, 40% salt Dialysis Tube = 20% water, 80% saltWill water move into the tube or out of the tube? 3. Beaker = 10% water, 90% sugar Egg = 60% water, 40% other moleculesWill water move into the egg or out of the egg? 4. Beaker = 100% water Egg = 50% water, 50% sugarWill water move into the egg or out of the egg?
Osmosis in Red Onions (Plant Cells)
Demo
Egg in Vinegar!
Celery in water and salt water
Dialysis tubing and starch solution
Osmosis worksheet
Answer the questions on the handout. Use your notes to help you answer the questions.
