the terms used to describe solutions and how those solutions are transported through biological membranes.
       Experimentation on organisms to determine the effects of changing solute concentration on biological membranes.
       Anticipating (i.e. hypothesizing) the experimental results of an experiment based on the knowledge you are
       presented with.  Will a potato placed in distilled water gain or lose weight?
       Analyzing and interpreting the results of an experiment by creating a Graph or Figure.

In the first week you have been exposed to a key biological concept:

All living cells must adapt to or regulate the movement of fluids through their membrane.

Also, you have learned and implemented a scientific experiment just as many researchers do in modern science.  Continue
and concretize your learning by studying the material below.

Optional readings (in the Discover Biology textbook):
pp. 107-110, 519-520, and 521-525.

                                           Osmosis Study Guide

1. What is the difference between simple diffusion and osmosis?

2. If there is net movement of water from solution A to solution B, then solution B is (hypo, hyper, isotonic) to solution A?

3. During osmosis water particles move in only one direction. (T/F)

4.  When viewing a de-shelled egg, you notice that the egg is swelling up.  What is causing the cells to
swell?  From this information you can conclude that the solution outside the cells is of what tonicity to the solution inside
the cells.

5.  A potato cell is isotonic in a solution of 70% water/ 30% sucrose.  It is placed in a solution of 20% water/ 80% sucrose.
Water will move _________(into/out of) the cell?

6.  If I drink pure water, is it dangerous? Why/Why not?

Other Links on the Web

Animated Osmosis-Portland State University's site on osmosis.
 

If you absolutely must have some recreation but know that you still need to study some biology, rent the animated comedy
Osmosis Jones.  Warning:  you probably will not learn very much about diffusion and osmosis

answers to study guide:

    1.Diffusion is the random movement of water or other particles that is driven by collisions with one another. Osmosis
       is a type of diffusion that is more selective than random diffusion because there is a membrane involved that allows
       the movement of water but not other particles.  The results of osmotic diffusion is that water attempts to equilibrate
       its own concentration by moving towards areas of higher solute concentration.
    2.hypotonic
    3.False.  Because osmosis is a type of diffusion the water is randomly moving in all directions- BUT, the net movement
       of water is always down its concentration gradient.  tricky, tricky..
    4.The egg cells are likely swelling due to the movement of water into the cell.  The solution outside the cells is
       hypotonic (i.e. solute concentration is lower outside) to the inside of the cell.
    5.Because the sucrose concentration outside the potato cell increases from the isotonic state of 30% to 80%, the
       water inside the cell will osmotically diffuse out of the cell.
    6.Yes, prolonged exposure to pure water can be dangerous!  Because the solute concentration within your cells is
       higher (hypertonic) than pure water, the water will osmotically diffuse into your cells causing them to burst or lyse.
       You have seen the effects of this after swimming when your skin becomes waterlogged.
 
 

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