Red Onion Cell Plasmolysis Lab

Notes/Bellwork: Thurs,.Oct 6, 2016: write the following: Plasmolysis: process in plant cells where the plasma membrane pulls away from the cell wall due to water through osmosis. Turgor Pressure (turgidity): the main pressure of the cell contents against the cell wall in plant cells and bacteria cells. Osmotic Pressure: pressure that must be applied to prevent osmotic movement across a selectively (semi) permeable membrane

IN PLANTS: Because of the Cell Wall… Turgor Pressure (turgidity): the main pressure of the cell contents against the cell wall in plant cells and bacteria cells, determined by the water content of the vacuole, resulting from osmotic pressure,

When this happens, cells are no longer rigid and the plant loses structure, giving the "wilty" appearance. http://www.youtube.com/watch?v=H6N1IiJTmnc&feature=related

Salt solutions affect cells. When a cell is in a hypotonic solution water will enter the cell and in will swell osmosis onion cell. When the cell is in a hypertonic solution water will leave the cell and it may shrink or go through something called plasmolysis.

Materials: red onion epidermis forceps dropper distilled water, 5% or higher NaCl (table salt) solution paper towels microscope slide cover slip

For the Substitute: For Friday start the slide show after this slide Have the students write down the bell work and then show them the answer slide The click on the link and show the youtube videos oon the subject

Bellwork: Fri. Oct. 7, 2016 1. ___ = red onion cells in distilled H2O 2. ___ = red onion cells in salt H2O 3. ___ = cells with the greatest turgor pressure 4. ___= plasmolyzed cells On your lab: A: indicate relative proportions of salt & water inside & outside the onion cells when placed in distilled water solution - use arrows to show which way water moves.. B :indicate relative proportions of salt & water inside & outside the onion cells when placed in the saline (salt) solution - use arrows to show which way water moves.. A B

Bellwork: Fri. Oct. 7, 2016 LABEL THIS ON YOUR LAB: 1. _A__ = red onion cells in distilled H2O 2. _B__ = red onion cells in salt H2O 3. _A_ = cells with the greatest turgor pressure 4. _B_= plasmolyzed cells LABEL THIS ON YOUR LAB: A: indicate relative proportions of salt & water inside & outside the onion cells when placed in distilled water solution - use arrows to show which way water moves.. B :indicate relative proportions of salt & water inside & outside the onion cells when placed in the saline (salt) solution - use arrows to show which way water moves.. A B

http://www.kscience.co.uk/animations/plasmolysis.htm http://www.youtube.com/watch?v=gWkcFU-hHUk

Now finish the lab, done forget to label your cell with: The cell wall (in all six circles) The cell membrane (in all 6 circles) The direction the water is moving (in all six circles) Make sure you shade in the cell purple as you see it.

END for Friday

Label and put into your notebooks… nucleolus

Physical changes in the potato cores 0% sucrose 10% sucrose 20% sucrose Day 1 Day 2 Change Length 3cm 3.2cm +0.2cm ----- 2.7cm -0.7cm Diameter 1.5cm 1.6cm +0.6cm 1.4cm -0.1cm Mass 1.2g 1.4g +0.2g 1g -0.2g Volume 1mL 1.2mL +0.2mL .98mL -0.2mL Which solution was hypertonic to the potato? How did you know? Which solution was hypotonic to the potato? Which solution was isotonic to the potato?

be http://www.youtube.com/watch?v=gWkcFU-hHUk http://www.kscience.co.uk/animations/animal_cell.htm