Some fab real time osmosis videos to set the mood! Osmosis in Cells Some fab real time osmosis videos to set the mood!

5 days ago Today Group Starter Activity Mr and Mrs Martinez went on holiday to Acapulco for a few days. When they came back their favourite plant looked like this! Explain the changes in terms of water movement 5 days ago Today

Why is osmosis important? Plants rely on the movement of water through them: Water always moves to areas of lower water concentration. Root hairs take in water from the soil by osmosis.

Plants- Water moving in We say that the cell is turgid. Water moves into a plant cell. The cell wall stops the cell from bursting. Turgid cell. Vacuole is filling all the space and pushing against cell wall SQA LO: Turgid, flaccid,plasmolysed- root hairs, cells to xylem vessel This is useful as it gives plant stems support

Cell turgor pressure

Plants- Water moving out When water moves out of the plant cell vacuole, by osmosis, it becomes flaccid Flaccid cell. Vacuole is much smaller and taking up less space If a lot of water leaves the cell, the cytoplasm starts to peel away from the cell wall and we say the cell has undergone plasmolysis.

Plasmolysis

Osmosis in Plant Cells (ie concentrated solution outside) Low water concentration outside the cell (ie concentrated solution outside) Equal water concentrations inside & out (ie equal solute concentrations inside & out) High water concentration outside the cell (ie pure water or dilute solution outside)

Animals- Water moving in Animal cells have no cell wall to stop the swelling, just a flexible cell membrane. If an animal cells are put in pure water (HWC) they take in water by osmosis until they burst. Add about contractile vacuole for osmoregulation (joat w/s p9) In eg Paramecium- features of both animal and plant cells? haemolysed normal turgid then burst

Animals- Water moving out If an animal cells are put in a concentrated solution (LWC) they lose water by osmosis until they become shrunken or haemolysed. haemolysed normal http://zoology.okstate.edu/zoo_lrc/biol1114/tutorials/Flash/Osmosis_Animation.htm

Quick Quiz- Osmosis What is a partially permeable membrane? Which substance moves by osmosis? What happens to plant cells that take up water by osmosis, and what do you call the cell? What happens to plant cells that lose water by osmosis, and what do you call the cell? What does ‘haemolysed’ mean? How does it happen? A membrane that only lets small molecules through it Water, H2O The cells become ‘full’ of water and are called turgid The cytoplasm comes away from the cell wall and the cells are called plasmolysed. Animals cells which have lost water become shrunken and are called haemolysed.

Now try your osmosis practice problems!