Study Guide 3
Last revised: Tuesday, January 29, 2002
Topic: Chemicals in the Cell II.
Chapters 3 and 4.


Chapter 3. This short chapter deals with properties of water, including the concept of dissociation, acids and bases, pH, buffers, and molarity.

  1. Terms. Be able to recognize and correctly apply the following terms:
    Adhesion
    Cohesion
    Surface tension
    Specific heat
    Solvent
    Solute
    Hydrophilic
    Hydrophobic
    Molecular weight (Formula weight)
    Mole
    Hydrogen ion (H+)
    Hydroxyl ion (OH-)
    Acid
    Base
    pH
    Buffer
    Weak (partial) dissociation
    Strong (full) dissociation


  2. Water is very polar. One result of this is that water interacts with itself to form extensive weakly-bonded structures. What type of bond is involved?
  3. What's the difference between adhesion and cohesion?
  4. Compare the specific heat of water with that of other liquids such as alcohol. Is it higher, the same, or lower? Why?
  5. Relative to the previous question, imagine an organism whose interior liquid was 70% alcohol instead of water. What effect would this difference have on the organisms ability to dissipate heat generated during metabolism or activity?
  6. Identify four properties of water that are of significance to life.
  7. How is pH defined? How is a mole defined?
  8. What is the pH of pure water? What is the concentration of H+? Of OH–?
  9. Is a pH of 6 more acid or less acid than a pH of 7? How many more H+ ions are present at pH 3 than at pH 7? What is the concentration of H+ in a pH 3 solution?
  10. The atomic weights of several elements are: C = 12 daltons; O =16 daltons, H =1 dalton. How many grams of pure acid (CH3COOH) are needed to make 1 liter of solution 0.2 molar in acetic acid?
  11. How does a strong acid differ from a weak acid? How does a base differ from an acid? Give an example of each.
  12. If the (H+) concentration of a neutral, buffered solution were suddenly made
    10-8 M, what would be the result (choose one)?
    (a) there would be more H+ than at neutral pH;
    (b) the buffer would dissociate to release more H+;
    (c) the buffer would soak up more H+



Chapter 4. This short chapter introduces properties of Carbon and the basic "rules" for building organic molecules. It also describes the handful of important functional groups found in biological molecules. These groups are like molecular "signatures" -- once you know them, you can look at a molecular structure and actually guess some of its properties and where it might be found in a cell. Learn them!

  1. Terms. Be able to recognize and correctly apply the following terms:
    Organic molecule
    Inorganic molecule
    Branched chain
    Unbranched chain
    Ring (cyclic) molecules
    Isomer
    Enantiomer
    Hydroxyl group
    Carbonyl group
    Aldehyde
    Ketone
    Carboxyl group
    Amino group
    Sulfhydryl group
    Phosphate group

  2. What are isomers? Why are isomers important in biology?
  3. Be able to recognie the difference between structural isomers, geometric isomers, and enantiomers
  4. What is a hydrocarbon?
  5. Certain groupings of common elements are best understood as “functional groups”, with characteristic properties. What are the names and “signature features” of each of the following functional groups?
    —C—H
    —O—H
    —C=O
    —COOH
    —NH2
    —SH
    —O—PO3=

[ top ][ Study Guide Index Page ][ Practice Quiz Index Page ][ Bio 107 home page ][ Dr. Terry home ][ Univ. of Conn. ]