Chapter 2:   Chemistry of Life

I. Nature of Matter 

A. Atoms
       Smallest division of matter that retain properties of elements.  Made of 3 subatomic particles:

1.Electrons: Outside nucleus; negative charge.
2.Protons: In nucleus; positive charge.
3.Neutrons: In nucleus; no charge.

Draw Atom of Helium

B. Bonds
Bonds: Combine two or more atoms.
       
      1. Covalent Bonds: Sharing of electrons between two nonmetals.
        
        2. Ionic Bonds: Bond between a metal and nonmetal 

The Periodic Table: Metals to left of stairs, Nonmetal to right of stairs

Ionic or Covalent?
NaCl

H2O

Li2O

CO2

II. Water

Water – The solvent of life. 
              Draw charges on water molecule:

Properties of Water:
A. Unequal sharing of electrons due to oxygen’s strong pull on negative electrons.  Called hydrogen bond, or polar bond.

B. Water is excellent solvent (dissolves things) because of its charged molecules (interact with other charged particles, like little magnets).

C. Water has high specific heat, or ability to store heat energy.

D. Water is cohesive, meaning its molecules stick to one another 

III. Aqueous Solutions

A.  Mixture:  Two or more substances mixed together but not chemically bonded  
           together.
      
      1. Solutions: Substances uniformely distributed.

Types of Solutions
0.	Solvent – the main ‘ingredient,’ often does the dissolving (water is the most universal solvent in the world)
1.	Solute – What is dissolved.

2.	Acids – Special solution with hydrogen ions in solution – hydrogen ions are the most reactive ions known.
3.	Bases – Solutions with hydroxide ions in solution (OH  ).
4.	pH – The scale used to measure acids/bases 1 acid/ 7 neutral / 14 base
5.	Strong acid plus strong base – neutral water 

IV. Chemistry of Living Things

A.     Inorganic Compounds – compounds not formed by living things (usually don’t  
                                                    contain carbon – exception is carbon dioxide.

B.  Organic – Organic means ‘made by living things.’ Most organic compounds  
         contain carbon. Carbon has four electrons in its valence cloud, wants to form 4   
          bonds.  It has the ability to form huge molecules and long chains.

C.   Polymers – Special type of compounds made of smaller monomers.

V. Compounds of Life – 

All organic molecules can be broken into four categories:
Carbohydrates, Lipids, Proteins, Nucleic Acids

A.	Carbohydrates: As the name implies (“carbo” for carbon and “hydrate” for water) these compounds often have a ratio of 1 carbon per 1 H20 molecule.  
       Examples: sugars, starch, wood (cellulose)

       The monomer?  a monosaccharide (like glucose)

     The polymer? disaccharide up to polysaccharide. 

       1. Sugars:  Immediate energy for cell (glucose) or, at least, quickly used   
          energy.
    
          Glucose: 
           A monosaccharide

        2. Polysaccharide: Many monosaccharides covalently bound together.

          Example: Starch, a polysaccharide, acts as long-term stored energy for   
                            plants.

         Example: Glycogen, a polysaccharide, acts as long-term stored energy for   
                           animals.

B.  Lipids:  Used as energy stores (high energy per gram).  Many carbon-hydrogen bonds (ratio of H:O greater than 2:1)
1. Examples: Fats, waxes, oils

2.  Useful for cell membranes, stored energy, insulation.

     3. Saturated fat: Maximum hydrogens; all single bonds; limit to 10% of your diet.

      4. Unsaturated fat: At least one double bond; usually liquid at room temperature; healthier fats.

Stolen from: http://kentsimmons.uwinnipeg.ca/cm1504/lipids.htm

                           

C.    Proteins: These contain nitrogen.  Useful as they make enzymes.

  1.  Examples: hair, muscle, enzymes

  2.   Monomer? Amino acids (we must obtain 8 essential AA in our diet)

  3.  Polymer? Polypeptide chain (protein)

        4. Enzyme: a biological catalyst that speeds up a chemical reaction (makes life      possible).  Follow in class and learn the model (look at page 41 in the textbook)

D.  Nucleic Acid – Used to store genetic information (DNA, RNA)

VI.  Enzymes

   A.Enzyme: a biological catalyst that speeds up a chemical reaction but isn’t used   
                        up in the reaction.
   
   B.Reactants: Enter a reaction.
       Products: The products resulting from a  reaction.
  
  C.   CO2 + H2O   C6 H12 O6 + O2

   D. Enzyme Vocabulary:
         1. Substrate: What enters the reaction.
         2. Active Site: Where the substrates react with  enzyme. 
         3.  Enzyme: Protein that isn’t altered in the  
                       course of the reaction.

E. What affects enzymes?
     1. Heat: Heat increases molecular motion, changing shape of enzyme.
      2.  pH: Acid and bases can digest bonds, changing shape of enzyme.
      3. Boiling: Extreme heat can denature an enzyme, permanently altering the molecule.