Passive transport notes

Monday November 12^th

Molecules naturally move from an area of High concentration to Low concentration.

If I wanted to increase the rate of diffusion of salt molecules in water what are three things I could do?

1.  Increase the temperature of the water

2.  Add pressure

3.  Either add more salt, or decrease the amount of water (both of which would increase the salt concentration)

Once there is an equal concentration of salt molecules throughout the beaker, how are the molecules now moving? Randomly (remember - molecules are ALWAYS moving!!)

What is the name of the state they are now in?

Dynamic Equilibrium (Dynamic meaning that while the molecules are not moving from high to low concentration since the concentration is equal everywhere, the molecules are still dynamic - still moving)

After this we continued with notes on passive transport.  While doing these notes I set up the following demonstration to show iodine moving across a semi permeable membrane.

 Below is an image of a bag full of corn starch. In just water it remains white. When placed in iodine - the iodine molecules were able to move across the membrane into the bag. We know this because the corn starch turned a bluish black color. In the presence of iodine, complex carbohydrates turn this color.

Bag in water

Bag once placed in iodine