Red Onion Cell Plasmolysis Lab NotesBellwork Wed Oct
Red Onion Cell Plasmolysis Lab
Notes/Bellwork: Wed. Oct 9, 2019: write the following: Plasmolysis: plant cell: when the cell membrane pulls away from the cell wall because water leaves cell by osmosis. Turgor Pressure (turgidity): main pressure of cell contents against cell wall in plant & bacteria cells. Osmotic Pressure: pressure applied to prevent osmotic movement across a selectively (semi) permeable membrane (build up cell or turgor pressure) turgor pressure
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=H 6 N 1 Ii. JTmnc&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 Na. Cl (table salt) solution paper towels microscope slide cover slip
Bellwork: Thurs. Oct. 10, 2019 1. ___ = red onion cells in distilled H 2 O A 2. ___ = red onion cells in salt H 2 O 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. . B
Bellwork: Thurs. Oct 11, 2019 1. _A__ = red onion cells in distilled H 2 O A 2. _B__ = red onion cells in salt H 2 O 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 B
• http: //www. kscience. co. uk/animations/plas molysis. htm • http: //www. youtube. com/watch? v=g. Wkc. FU -h. HUk
Now finish the lab, don’t 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
Label and put into your notebooks… nucleolus
be • http: //www. youtube. com/watch? v=g. Wkc. FU -h. HUk • http: //www. kscience. co. uk/animations/ani mal_cell. htm
Old stuff
Physical changes in the potato cores 0% sucrose 10% sucrose Day 1 Day 2 Change Day 1 Day 2 Length 3 cm 3. 2 cm +0. 2 cm 3 cm Diameter 1. 5 cm 1. 6 cm +0. 6 cm 1. 5 cm 20% sucrose Change Day 1 Day 2 Change ----- 3 cm 2. 7 cm -0. 7 cm ----- 1. 5 cm 1. 4 cm -0. 1 cm Mass 1. 2 g ----- 1. 2 g Volume 1 m. L 1. 2 m. L +0. 2 m. L 1 m. L ----- 1 m. L 1. 4 g +0. 2 g 1 g . 98 m. L -0. 2 m. L 1. Which solution was hypertonic to the potato? How did you know? 2. Which solution was hypotonic to the potato? How did you know? 3. Which solution was isotonic to the potato? How did you know? -0. 2 g
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