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Osmosis. Honors Biology. Osmosis. Remember – a semi-permeable membrane MUST be present, otherwise it’s just diffusion 3 types of solutions. 3 examples of Osmosis. Cells have molecules of solute (salt, sugar, etc.) inside them.
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Osmosis Honors Biology
Osmosis • Remember – a semi-permeable membrane MUST be present, otherwise it’s just diffusion • 3 types of solutions
3 examples of Osmosis • Cells have molecules of solute (salt, sugar, etc.) inside them. • Cells will either lose water, gain water, or have an equal flow of water DEPENDING ON how much water AND solute is outside the cell.
1. Hypertonic • Has too many particles (solute) (“too hyper”) • Too sweet, too salty • A cell placed in a hypertonic solution - water would flow OUT of the cell, causing it to shrivel and perhaps die • Think of water moving TOWARDS the area with the most solute
Hypertonic • In animal cells (shrivels) • In plant cells (plasmolyzed = shrink on inside only) The outside of the cell is “hypertonic” relative to the inside of the cell.
2. Hypotonic • Means not enough solute (or too much water) • A cell placed in a hypotonic solution - water would flow INTO cell, causing it to swell, and perhaps burst/die • Cell would have more solute (salt) relative to the outside of the cell
Hypotonic • In animal cells (lysis = burst) • In plant cells (turgid = swollen) • Outside of cell is “hypotonic” relative to inside Plant cell - cell walls keep cell from bursting
Ways to remember • If cell placed in hypertonic solution - “you are too hyper, go outside and play = water flows out” • If cell placed in hypotonic solution - “if you don’t come inside you will get hypothermia = water flows into cell”
3. Isotonic • Means equal concentration of solute compared to the cell • When a cell is placed in an isotonic solution, equal amounts of water enters and exits cell • Cell size remains constant
Isotonic • Flaccid = means “loose” (plant cells) • Just called “normal” in animal cells
Hyper and Hypo Water moves “toward” area that has more solute (particles).
These are relative terms • Be careful! If a cell is placed into a hypertonic solution: • The solution is hypertonic relative to the cell • The cell is hypotonic relative to the solution
Practice 1. If this cell (50% solute) is placed into a solution (that is 80% solute), which way will water flow? What is the solution? The cell? What % water is the cell? The solution?
Another practice 2. This cell is 60% solute and is placed in a solution that is 45% solute. Which way will water flow? What is the solution? The cell? What % water is the cell? The solution?