Red Onion Cell Plasmolysis Lab NotesBellwork Tues Oct

Red Onion Cell Plasmolysis Lab

Notes/Bellwork: Tues. Oct 10, 2017: write the following: Plasmolysis: plant cell process where plasma membrane pulls away from the cell wall due to water leaving the cell through osmosis. Turgor Pressure (turgidity): main pressure of the cell contents against the cell wall in plant 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=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

• http: //www. kscience. co. uk/animations/plas molysis. htm • http: //www. youtube. com/watch? v=g. Wkc. FU -h. HUk

Bellwork: Wed. Oct. , 2017 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: Wed. Oct. 11, 2017 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

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 +0. 2 g 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 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