1. 10/11/10 BIOL 1441-030 Wed 11:00 – 12:50 LS 200 BIOL 1441-033 Thu 3:00 – 4:50 LS 207 BIOL 1441-037 Fri 11:00 – 12:50 LS 200 Heath Blackmon LS 459 Office Hours: 10:30-12:00 Tue and Thu heath.blackmon@mavs.uta.edu

2. Osmosis and Diffusion

3. Diffusion The movement of molecules or ions from an area of higher concentration to an area of lower concentration Typically refers to the movement of a solute within a solvent.

4. Diffusion 3 factors influence diffusion 1. Temperature: increase will increase the speed of diffusion because it increases the motion of molecules 2. Molecule Size: larger molecules diffuse more slowly because it is harder for it to move through the spaces in the medium 3. Concentration gradient: if the difference between the concentrations of high and low regions are greater, then diffusion proceeds faster.....therefore, diffusion slows as the concentrations approach one another.

6. Osmosis The diffusion of water molecules across a semi- permeable membrane. Water moves from high concentration to low concentration Solution with higher concentration is hypertonic in relation to the other solution Solution with the lower concentration is hypotonic in relation to the other solution If solutions are equal, then they represent isotonic solutions Rem: these terms are relative and only used in comparison...much like taller, shorter, thicker, thinner

7. Osmosis At equilibrium, water is moving across the membrane at equal rates. This would be exhibited in an isotonic situation.

10. The procedure for the egg experiment begins on page 79. Each table will use one egg. You will take measurements every 15 minutes for one hour. You will exchange data with an adjacent table for the other solution. You will use this experiment and your observations of Elodea to write your lab report. The procedure for dialysis tubing experiment is on page 90.

11. Exercises Perform Exercise 2 and Exercise 3. Write your hypothesis for each experiment Perform the experiments Record your data... You will be producing a line graph with your egg data Write a lab report using the “Instructions for Writing a Lab Report” on the IntroLabs home page You need three references, with at least two of them being primary.