Spring.wmf (18300 bytes) Plant Physiology (Biology 327)  - Dr. Stephen G. Saupe;  College of St. Benedict/ St. John's University;  Biology Department; Collegeville, MN  56321; (320) 363 - 2782; (320) 363 - 3202, fax;    ssaupe@csbsju.edu

Water Properties Quiz

Short Answer Questions

  1. Water is a liquid at room temperature.  Explain why this is unusual and then explain why it occurs.
  2. Explain why a bellywhopper into a pool of ammonia wouldn�t hurt as much as one in water.
  3. Water is transparent to light.  Explain why this is biologically important.
  4. How does water affect the shape of molecules?


Fill-in-the-Blank Question:

1   Term for a negative pressure
2   Air bubbles that escape from a liquid under reduced pressure
3   Mass movement of molecules from one area to another following a pressure gradient
4   Random movement of individual molecules from one area to another
5   Integral proteins in the membrane that acts as a channel for water passage
6   Movement of water up a thin tube
7   Universal solvent
8    Substance dissolved in a solvent

Cohesion/Adhesion Matching For each of the following, indicate if it is an example of cohesion (C), adhesion (A), or both (B)

1   attraction of likes
2   attraction of unlikes
3   water molecules hydrogen bond to one another
4   water is absorbed by a paper towel
5   water moves up a thin column


Sketching Question   Assume the circle below represents a sodium ion.  Draw in water molecules to represent the hydration shell surrounding this ion. 



 Multiple Choice Questions

1.  A lake is an example of a ________ environment.
          a.  hydric       b.  mesic       c.  xeric

2.  Succulent leaves, thick cuticle, stomata sunken in chambers and reduced leaf size is characteristic of a plant living in a _________ environment.
          a.  hydric       b.  mesic       c.  xeric

3.   Some insects can "walk on water" because:
            a.  water is adhesive           c.  water has a high surface tension
            b.  water is transparent       d.  water can expand as it freezes

 4.  Which of the following bonds is most likely to be �polarized?�
          a.  C � H                 d.  O - H
          b.  C � C                 e.  H - H
          c.  O - O

Calculation/Conversion Question:  Megapascal is the metric unit for water potential.  It is a pressure unit.  1 MPa is approximately equal to 10 atmospheres or 10 bars or 147 pounds per square inch.  Convert the following.

1 Racing bicycle tire (120 psi) =   MPa
2 Automobile tire (35 psi) =   MPa
3 Typical plant cell pressure (0.5 MPa) =   psi
4 Home plumbing pressure (30 psi) =   MPA
5 Water pressure under 15 feet (0.05 Mpa) =   psi

Water Property Matching
Match each of the following with the appropriate property of water. 

a. Density decreases on crystallization e.  High surface tension
b.  Heat of fusion     d.  Specific Heat
c.  Heat of vaporization  f.   Tensile strength
1   explains why people perspire and plants transpire
2   explains why desert plants are succulents
3   explains why raindrops are round
4   explains why water acts like it has a skin
5   explains why water can move up a thin tube
6   ice floats
7   involved in cooling organisms
8   used by desperate farmers to protect fruit crops from frost damage
9   thermal buffer
10   water is a thermal buffer
11   water resists evaporation
12   water resists freezing
13   water resists temperature changes


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Last updated:  02/13/2009     � Copyright  by SG Saupe