empirically in many cultures long before people knew about cells or osmosis. Now, students can use their understanding of osmosis to predict that drying and salting food will prevent or reduce the growth of spoilage-causing bacteria and molds. Follow-Up Activities Cell Membrane Structure and Function () This minds-on activity includes two hands-on experiments and numerous analysis and discussion questions to help students understand how the molecular composition and organization of a cell membrane result in its selective permeability. Students learn how the phospholipid bilayer and membrane proteins play key roles in the cell membrane function of regulating what gets into and out of the cell. Specific topics covered include ions, polar and nonpolar molecules; simple diffusion through the phospholipid bilayer; facilitated diffusion through ion channels or carrier proteins; active transport; exocytosis and endocytosis. (This activity is aligned with NGSS.) You may want to have your students carry out a follow-up osmosis experiment, using one of the following options: Analyze osmosis in Elodea or moss cells and osmosis across dialysis tubing; see "Diffusion and Osmosis" (available at ). Analyze osmosis across dialysis tubing, in pieces of potato, and in onion skin; see "Osmosis and Diffusion" (available at ). Use microscopes, Elodea and various chemicals to study osmosis and rates of diffusion across the cell membrane of molecules of different size and hydrophobicity; see "Diffusion across Biological Membranes" ( ). Should you drink sports drinks? When? Why? (). The questions in this activity help students to understand the effects of consuming sports drinks and when and how the consumption of sports drinks can be beneficial or harmful. This activity provides the opportunity to review some basic concepts related to osmosis, cellular respiration, mammalian temperature regulation, and how our different body systems cooperate to maintain homeostasis. Sources for Figures in Student Handouts Figure in question 14 adapted from Biology A Guide to the Natural World, 5th edition, – by Krogh All other figures were drawn by the author. Appendix A Common Hypothesis about the Mechanism for Osmosis – Na+, Cl-, and the water molecules that are bound to these ions cannot cross the selectively permeable membrane. Only free water molecules (water molecules that are not bound to ions or other dissolved substances) can cross the selectively permeable membrane.
empirically in many cultures long before people knew about cells or osmosis. Now, students can use their understanding of osmosis to predict that drying and salting food will prevent or reduce the growth of spoilage-causing bacteria and molds. Follow-Up Activities Cell Membrane Structure and Function () This minds-on activity includes two hands-on experiments and numerous analysis and discussion questions to help students understand how the molecular composition and organization of a cell membrane result in its selective permeability. Students learn how the phospholipid bilayer and membrane proteins play key roles in the cell membrane function of regulating what gets into and out of the cell. Specific topics covered include ions, polar and nonpolar molecules; simple diffusion through the phospholipid bilayer; facilitated diffusion through ion channels or carrier proteins; active transport; exocytosis and endocytosis. (This activity is aligned with NGSS.) You may want to have your students carry out a follow-up osmosis experiment, using one of the following options: Analyze osmosis in Elodea or moss cells and osmosis across dialysis tubing; see "Diffusion and Osmosis" (available at ). Analyze osmosis across dialysis tubing, in pieces of potato, and in onion skin; see "Osmosis and Diffusion" (available at ). Use microscopes, Elodea and various chemicals to study osmosis and rates of diffusion across the cell membrane of molecules of different size and hydrophobicity; see "Diffusion across Biological Membranes" ( ). Should you drink sports drinks? When? Why? (). The questions in this activity help students to understand the effects of consuming sports drinks and when and how the consumption of sports drinks can be beneficial or harmful. This activity provides the opportunity to review some basic concepts related to osmosis, cellular respiration, mammalian temperature regulation, and how our different body systems cooperate to maintain homeostasis. Sources for Figures in Student Handouts Figure in question 14 adapted from Biology – A Guide to the Natural World, 5th edition, by Krogh All other figures were drawn by the author. Appendix – A Common Hypothesis about the Mechanism for Osmosis Na+, Cl-, and the water molecules that are bound to these ions cannot cross the selectively permeable membrane. Only free water molecules (water molecules that are not bound to ions or other dissolved substances) can cross the selectively permeable membrane.
OsmosisTeachPrep.docx