1 / 12

AP Lab 4: Osmosis and Diffusion

AP Lab 4: Osmosis and Diffusion. Purpose. 1. Investigate processes of diffusion and osmosis in a model membrane system, and 2. Investigate effect of solute concentration on water potential as it relates to living plant tissues. Key Concepts.

bena
Télécharger la présentation

AP Lab 4: Osmosis and Diffusion

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. AP Lab 4: Osmosis and Diffusion

  2. Purpose 1. Investigate processes of diffusion and osmosis in a model membrane system, and 2. Investigate effect of solute concentration on water potential as it relates to living plant tissues.

  3. Key Concepts • Diffusion: The mvmt of materials from high to low concentrations…passive transport = no energy. • Osmosis: Mvmt of water from high to low.

  4. Key Concepts

  5. Key Concepts: Water Potential • Tendency of water to leave one place in favor of another. • PP: amt of pressure in cell • SP: solute concentration: As solute is added, value for solute potential becomes more negative  decreases wp.

  6. Key Concepts: Molarity • 1 M Sucrose: 342.3 g/mol + 1000 mL (1 L) • 1 M NaCl: 58.44 g/mol + 1000 mL (1 L) • To make a 0.5 M, cut the grams amount by ½.

  7. Procedure Pt 1 • 1) Tie off one end of a wet dialysis bag. Fill with a 10 mL sugar/salt solution of a concentration (like 1M NaCl). Tie off and weigh. • Fill cup with diff. sugar/salt concentration (like 0.5M NaCl). • Let sit for 30 mins. • Reweigh

  8. Procedure Part 2 • 1) Obtain 6 wet dialysis bags. • 2) Fill with different concentrations of sucrose. Weigh to get initial weights (OM, 0.2 M, 0.4 M, 0.6 M, 0.8 M, 1 M) • 3) Place dialysis bags in distilled water. • 4) Wait and then weigh bags to see what happened. Graph results. • Hint: Be sure that the entire dialysis bag and tie are submerged!

  9. Procedure Part 3 • 1) Like Ex 2, but w/ potatoes. 1st weigh potatoes. • 2) Put potatoes (no skin) in solutions of varying sucrose concentrations. • 3) Calculate weight gain or loss.

  10. Procedure Part 4 • Use the value for the molar concentration of the potato cores that you obtain in Exercise 3 to determine the water potential for the potato cells. • Calculate water potential (pressure potential on open beaker is zero).

  11. Procedure Part 5 • Watch the effect of placing an onion cell into a solution that has a lower or higher concentration of water than the cell.

More Related