Kinetic energy, a root of energy stored in cells, causes molecules to hit into each other and move in new directions. Diffusion is the result of this contact. Diffusion is the random movement of molecules to an area of lower concentration from an area of higher concentration. Osmosis is a type of diffusion. This is the diffusion of water through a selectively permeable membrane from a region of higher water potential to a region of lower water likely. Water potential is the measure of free energy of water in a solution. A living system also contains an active transport to make movement of particles like ions that move against their concentration gradient.
The energy source ATP is used during this process to move the particles across the cell membrane. This experiment takes place to measure the diffusion of small molecules through dialysis tubing. This tubing acts as a selectively permeable membrane, allowing larger molecules to pass through, but slowly. Dialysis is the movement of a solute through a selectively permeable membrane. When the two solutions on either sides of the membrane are equal and no net movement is detected, the solutions are isotonic. This means that the solutions have the same concentration of solutes. If two solutions differ in the concentration of solutes that each has, the one with more solute is hypertonic. The solution that has less solute is hypotonic
Experiment 1: Diffusion
1. Elodea plant 2. Zipper plant 3. Hypotonic solution 4. Hypertonic solution 5. Light microscope
Experiment 2: Osmosis
1. 4 slides 2. Potato 3. Hypotonic solution 4. Hypertonic solution
Experiment 3: Ferrous
1. Ferrous Sulfate 2. Potassium Ferricyanide 3. Slides 4. A Ruler
* We, as a group, needed two potato slices, water, and a salt. * A potato slice was dropped into the tap water and the other slice into the salt. * Allow the potato slices to stand in the bowl for a minimum of 30 minutes. * At 0 minute nothing happened to both potato slices.
* After 10 minutes, the potato in water (hypotonic) became puff up and firm. * The potato in NaCl got smaller and wet. * After 20 minutes, the results of both potato slices were the same as 10 minutes results. At 30 minutes the potato in hypotonic became rigid.