Diffusion and Osmosis

What is diffusion?

• When molecules move from a low concentration to a high concentration

• When molecules move from a high concentration to a low concentration.

• When there is no movement of molecules

• When molecules move everywhere regardless of concentration

Which gummy bear was left overnight in salt water?

• Larger bear

• Smaller bear

If you are stranded at sea why is it safer to drink urine than sea water?

• One cup of sea water has enough sodium to poison you.
• Sea water is hypertonic to your cells and will only further dehydrate you.
• Sea water is too isotonic to your cells and you will absorb too much water.
• The salt will cause high blood pressure and you will die from a stroke.

A student noticed that placing wilted lettuce in a bowl of cool water caused the lettuce to become more crisp and firm. What is the best explanation for his observation?

• Water moved into the lettuce cells by active transport.
• Water moved into the lettuce cells by osmosis.
• Salt moved into the lettuce cells by diffusion.
• Water moved out of the lettuce cells by osmosis.

Where is there a low concentration of dye?

• at the bottom of cup
• in the color
• at the top of cup 
• no concenteraion gradient

Permeable means

• things can pass through
• the concentration levels are different
• it is permanent
• things are stuck

Osmosis is specifically.....

• diffusion of water molecules through a semi-permeable mebrane from an area of low concentration to an area of high concentration

• the diffusion of particles from an area of high concentration to an area of low concentration

• diffusion of water molecules through a semi-permeable membrane from an area of high concentration to an area of low concentration

• the diffusion of particles from an area of low concentration to an area of high concentration

Equilibrium is when....

• there is a large amount of substance on the inside of the cell and a small amount in the outside solution

• there is a small amount of substance on the inside of the cell and a large amount in the outside solution

• there is an equal amount of substance on either side of the cell membrane

• there are no particles on either side of the the cell membrane

During osmosis

• water moves from high to low concentration
• large or oddly shaped molecules move across a cell membrane
• water moves when energy is used
• proteins are built

In the given scenario what will happen?  An egg is placed in pure water for 48 hours.

• The egg will gain water and swell.
• Water will move in and out of the cell equally, and the cell with neither shrink nor swell.
• The egg will lose water and shrink.