Osmosis: Plant Cell Movement (PDF)

SLS Activity 2-1 Observe these plants What are some observable characteristics of these plants? Are they alive or dead? Why?  SLS Activity 2-2 The rose of Jericho Watch the video via the link on SLS - https://vimeo.com/ 25485145...

SLS Activity 2-1 Observe these plants What are some observable characteristics of these plants? Are they alive or dead? Why?  SLS Activity 2-2 The rose of Jericho Watch the video via the link on SLS - https://vimeo.com/ 25485145 Think-Pair-Share Why were the changes observed upon addition of water? Osmosis The net movement of water molecules from a region of higher water potential to a region of lower water potential across a partially permeable membrane. Red circle – water molecules Purple circle – solute molecules (eg. sugar molecules) Osmosis Water potential Refers to the tendency of water molecules to enter or leave solutions by osmosis is denoted by the Greek letter ψ (psi) and is expressed in units of pressure called megapascals (MPa). The potential of pure water is designated a value of zero Comparing water potential: Hypertonic, Hypotonic, Isotonic Hypotonic = less (solute) These are terms Isotonic = equal used relative to Hypertonic = more another solution!! Example: The cell sap of the potato cell is isotonic to the sucrose solution OR The cell sap of the potato cell has an equal water potential to the sucrose solution The cell sap of a leaf cell from the rose of Jericho is hypertonic compared to water ______________  SLS Activity 2-3 The rose of Jericho Based on your prior knowledge of the effects of osmosis on plant cells, draw & explain the expected appearance of a leaf cell in the rose of Jericho before & after the addition of water.  Net movement of Vacuoles expand, Water has a water molecules pushing the contents higher W.P. than occurs from water of the cytoplasm the cell sap of into cell sap of the against the cellulose via osmosis cell wall. Cells plant cells’ plant cells across vacuoles partially-permeable become turgid, membranes causing uncurling of the leaves Direction Compare of Process Effect movement What led to the ‘resurrection’ of the rose of Jericho? Which solution is hypertonic/hypotonic/isotonic to the RBC?  There is net Cell shrinks in size, RBC has a movement of water and assumes a higher W.P. molecules from RBC spiked form in than the via osmosis into solution across a shape. Cell becomes solution it partially-permeable crenated (process: was placed in membrane crenation). Direction Compare of Process Effect movement What led to the shrivelling of the red blood cell? Why is osmosis important in living things? Water uptake to allow Regulation of blood water plants to remain upright potential by kidneys Think-Pair-Share: What are some other examples of osmosis in living systems (plants & animals)? Why is osmosis important? Think about this! Should limp vegetables be thrown away immediately?