1. Can you die from drinking too much water? Water intoxication, or water poisoning, is a potentially deadly condition. How can drinking too much water kill you?

2. Remember – materials move across the cell membrane because of concentration differences. Diffusion occurs when molecules move from a high concentration to a low concentration. – Molecules like water, oxygen, & CO2 can move across cell membranes with diffusion. Osmosis is the diffusion of water from a low solute concentration to a high solute concentration.

3. Solvent vs. Solute In a sugar/water solution, which one is the solute & which is the solvent? Water is the SOLVENT; sugar is the SOLUTE.

4. Osmosis – movement of water from a low solute concentration to a high solute concentration Water wants to move towards the highest concentration of dissolved solutes. Will the water molecules flow to one side of this beaker? If so, which side?

5. The Environment Around the Cell The solute concentration in the solution surrounding a cell is important! – Too little or too much solute in a cell’s environment could cause cell death. There are 3 types of solutions a cell could be in: – Isotonic – Hypertonic – Hypotonic

6. Cell Tonicity

7. The solute concentration in a solution determines whether water will flow into or out of a cell.

8. Isotonic Solution The same concentration of solute on both sides of the cell membrane – Water will continue to move into & out of the cell at an even rate.

9. Hypotonic Solution Lower concentration of solute outside of the cell than inside of the cell – Higher concentration of free water molecules outside the cell – Water will move into the cell. Water flows into the cell towards the high concentration of solute.

10. Hypertonic Solution Higher concentration of solute outside of the cell than inside of the cell – Higher concentration of free water molecules inside the cell – Water will move out of the cell. Water flows out of the cell towards the high concentration of solutes, causing the cell to lose water.

11. What type of environment is this cell in? A.Hypertonic B.Hypotonic C.Isotonic D.Osmotic Hypertonic! Water will move out of the cell towards the higher concentration of salt. 20% salt 10% salt

12. A.Hypertonic B.Hypotonic C.Isotonic D.Osmotic Hypotonic! Water will move into the cell towards the higher concentration of salt. 10% salt 20% salt

13. A.Hypertonic B.Hypotonic C.Isotonic D.Osmotic Isotonic! There are equal concentrations of salt in & out of the cell, so water will move in & out at an even rate. 10% salt

14. Animal Cell Plant Cell If a cell takes in too much water, it will swell & may burst. If a cell loses water, it will shrink & lose shape.

15. HypotonicIsotonicHypertonic

16. Wilting Wilting occurs when a plant doesn’t get enough water & it begins to lose its shape. At the cellular level, what causes this? Plant cells store water in their vacuoles. When a cell loses water, the cell begins to shrink & lose its shape. Is this caused by a hypertonic, hypotonic, or isotonic solution? HYPERTONIC

17. How can drinking too much water kill you? Water intoxication occurs when a person drinks so much water, that there is an extra amount of water in the body fluids outside of cells.

18. Water Intoxication Water intoxication occurs when the water concentration is too high in the body fluids. The cells will take in tremendous amounts of water to try to get the levels back to normal. The cells will swell with water & will eventually burst. Is this caused by a hypertonic, hypotonic, or isotonic solution? HYPOTONIC

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