Cell Function and Diffusion

How to follow Lab Instructions… thoroughly! Example: Instructions for how to clean up after your dog! By Contributor - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=961254 To pick up after your dog, use your hand To pick up after your dog, use your hand that you covered with a plastic bag (turned inside-out).

How to follow Lab Instructions… Read entire list of Instructions. Gather materials. Label them. Follow Procedure step by step. Check off each completed step. Record data Analyze and conclude. Clean-Up!

Diffusion Movement of molecules from a higher to a lower concentration until equilibrium is achieved Dependent on temperature, size of molecules, and type of medium (solid, semi-solid, liquid, air) By JrPol - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=4586487

Types of Diffusion Air Liquid Semi-solid Semi-permeable membrane (Osmosis) Dialysis tubing Copyrighted free use, https://commons.wikimedia.org/w/index.php?curid=1353812 By Mike aus dem Bayerwald - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=7549241 By M.Mack - HS-Mannheim, Institut für technische Mikrobiologie, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=5239374

Diffusion Diffusion of methylene blue in agar (semi-solid) versus water (liquid) In which medium did the dye diffuse the fastest? © Kornelia Fillmer, CC BY-SA 3.0 https://photos.google.com/share/AF1QipNI7F0Ivn98mkVbccZHaZLZUf5g2B-0MeWxZig4RiIHK_ki4B0g4poDhu0I4mKdbg?key=R3h4N1MyMlFCRERIODBOczdrZEd5b3lVaFBJRXF3

Osmosis – Diffusion of Water across semi-permeable membrane 1. Where is the concentration of the solutes higher? = Hypertonic = Hypotonic = Hypertonic Semi-permeable membrane The other side must be Hypotonic

Hypertonic, Hypotonic, Isotonic -Tonicity, it’s all relative - Ted By pixabay.com, CC0 Public Domain, https://pixabay.com/en/boy-happy-teen-guy-dude-teenager-154336/ Jim Bill Is Jim tall?

Water moves. Always from “o” to “er” If solute molecules are too large and can’t move through membrane, then… Water moves. Always from “o” to “er” Water moves from Hypotonic to Hypertonic H2O Hypotonic Hypertonic

So same concentration on both sides In the end: Isotonic! So same concentration on both sides Number of solute molecules on either side do not change (they did not move!) H2O moved, making left side smaller (shrink) and right side bigger (expand, turgid or even burst) Isotonic Isotonic

Where is the concentration of solute higher? => Hypertonic => other side = Hypotonic Water moves from Hypotonic to Hypertonic From ‘o’ to ‘er’ What will happen? Hemolysis in animal cells (burst); Turgid in Plant cells H2O Hypertonic Hypotonic

Where is the concentration of solute higher? => Hypertonic => other side = Hypotonic Water moves from Hypotonic to Hypertonic From ‘o’ to ‘er’ What will happen? Hemolysis in animal cells (burst); Turgid in Plant cells 0.5% NaCl 0.9% NaCl H2O Hypertonic Hypotonic

Where is the concentration of solute higher? => Hypertonic => other side = Hypotonic Water moves from Hypotonic to Hypertonic From ‘o’ to ‘er’ What will happen? Crenation in animal cells (shrivel); Plasmolysis in Plant cells 1.5% NaCl 0.9% NaCl H2O Hypertonic Hypotonic

Tonicity Isotonic Hypertonic Hypotonic Relative concentration of solute (particles) or solvent (water) outside the cell compared to inside 3 Types Isotonic Hypertonic Hypotonic

Tonicity and red blood cells Check out tubes of prepared red blood cell (RBC) solutions RBCs are floating either in Hypertonic, Isotonic, or Hypotonic solution By Osmotic pressure on blood cells diagram.svg: LadyofHatsderivative work: Antoni Salvà (talk)This vector image was created with Inkscape. - Osmotic pressure on blood cells diagram.svg, GFDL, https://commons.wikimedia.org/w/index.php?curid=7861851

Tonicity and red blood cells By Zephyris - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=18401754

Tonicity and Elodea Cells Hypotonic Tap water Turgid – Turgor Pressure Hypertonic In 10% NaCl solution Water has left the cell across the plasma membrane Notice how cell membrane has shrunk away from cell wall and chloroplasts are all clustered in middle Plasmolysis By Cimice50 (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/a/a9/Cloroplasti_Elodea.jpg © Kornelia Fillmer, CC BY-SA 3.0 https://photos.google.com/share/AF1QipNHRhg4AkNftwXMWAa7Si_lRLAjOlcWMvdtckFrv6fSCVYYXP6l70Y21yd_o47orA?key=VVV4M052OGk5R2FENWNHU0tMNjMxOWJjekFFMEtn

Tonicity Plant Cells By LadyofHats - did it myself based on [1], [2] ,[3] and [4]., Public Domain, https://commons.wikimedia.org/w/index.php?curid=1685428

Testing for the presence of Starch and Glucose © Kornelia Fillmer, CC BY-SA 3.0 https://goo.gl/photos/oaz31khEprECqHDa9 Adding Iodine to water turns the color slightly amber (looks like tea) In the presence of Starch, the color turns dark Adding the blue Benedict’s reagent to a sample turns the color to blue. Heating the sample for 5 minutes will turn the sample orange if glucose is present. © Kornelia Fillmer, CC BY-SA 3.0 https://goo.gl/photos/oaz31khEprECqHDa9 © Kornelia Fillmer, CC BY-SA 3.0 https://goo.gl/photos/AMciWwwrF5HRJhLf7 © Kornelia Fillmer, CC BY-SA 3.0 https://goo.gl/photos/AMciWwwrF5HRJhLf7

Next Lab Read Exercise 5 in Lab Manual Post Lab Quiz 4 now open Deadline: Day before next Lab at 9:00pm © Kornelia Fillmer, CC BY-SA 3.0 https://goo.gl/photos/8Kh1Yv8Zf2oB7xkk6

Changes to the 1e Lab Manual Page 38 9. “Which solute did not diffuse across the dialysis membrane from the beaker?” Change the word “from the beaker” to “out of the tube” Page 38 add this questions: “10. If you would have tested the beaker liquid after waiting the 5 minutes in step 6 with Benedict’s reagent, heating the testing solution would have turned its color from blue to orange. Why?”

Activities Station A Station D* Station B Station C A: “To Do” page 36 Diffusion Semisolid “To Do” page 36 Diffusion Liquid (60 sec) B: “DEMO” page 37 – 38 Dialysis bags C: “To Do” page 40 Red Blood Cells D: “To Do” page 42 Plant Cell Tonicity* * Group “D” starts the potato strip for the entire class and records start time. Other groups skip this station until the 1 h wait time is over to record results. Station A Station D* Station B Station C