Most of the organic molecules you have been introduced to at this point have consisted of only carbon and hydrogen. Molecules consisting only of carbon and hydrogen are called hydrocarbons. These molecules are not very reactive and are nonpolar (do not dissolve in water). They will burn is the presence of oxygen when a high amount of activation energy is introduced. Gasoline and smaller gas molecules consists of hydrocarbons. 

 Biological molecules have distinctive properties which allows than to operate in their unique manner. These distinctive properties of organic molecules depends not only the hydrocarbons but also molecular components attached to the carbon skeletons. The molecular components are calle called functional groups. These functional groups will be involved in chemical and physical properties unique to the various biological macromolecules such as type of chemical reactions they may undergo and the solubility of that molecules in  water. There are six functional groups that are important in the chemistry of living things. Read the pages indicated by A-7 and study behavioral objectives 23 and 24. In your notes construct a table identifying the top six functional groups, draw their structural formula and list a few properties for each group. 

   hydrogen -H 

  hydroxyl  -OH 

  carboxyl  -COOH 

  amino  -NH₂ 

  phosphate  -H₂ PO₄ 

  methyl    -CH₃ 

  aldehyde    -CHOH 

                    O 
                     " 
  ketone-  C-C-C-C 
 

  sulfhydryl   -SH 

Some of the properties of these functional groups are: amino group consists of nitrogen, can bind with a  hydrogen bond thus making it a base, 

 hydroxyl group consists of a hydrogen bonded to an oxygen which in turn is bonded to a carbon skeleton, organic compounds containing hydroxyl groups are called alcohols, water is attracted to the hydroxyl groups thus making alcohols soluble in water (examples ethanol alcohol ((drinking alcohol - vodka, wine, etc.)) , methyl alcohol (wood alcohol) 

 aldehyde group consist of a carbon atom joined to an oxygen atom by a double bond and is located on the end  of a carbon chain 

 carboxyl group consists of an oxygen atom  double bonded to a carbon that is also bonded to a hydroxyl group (COOH), these are always fond on the end of a carbon chain and have acid properties 

 phosphate group consist of a phosphate anion attached to a carbon skeleton 

         O
          | 
 C-O-P=O  
          |
         O

methyl group consists of a hydrocarbon group (contains only hydrogen and carbon) and thus makes the molecule hydrophobic (nonpolar), these molecules will not mix with water. 

 sulfhydryl groups form covalent bonds with one another stabilizing protein chains. 

 In your notes draw each of these functional groups attached to a carbon skeleton. 

 Examine behavioral objective 24 and study the pages indicated by A-8 Write in your notes a paragraph explaining differences between an alcohol and a hydroxide. 

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2. Identify the functional group on the carbon skeleton shown in the  top figure. 

 Functional groups found in biological molecules. 

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3. Identify the functional group on the carbon skeleton shown in the second figure propanal. 

 Functional groups found in biological molecules. 

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4. Identify the functional group on the carbon skeleton shown in the third figure acetone. 

 Functional groups found in biological molecules. 

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5. Identify the functional group on the carbon skeleton shown in the fourth figure acetic acid. 

 Functional groups found in biological molecules. 

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6. Identify the functional group on the carbon skeleton shown in the fifth figure methylamine. 

 Functional groups found in biological molecules. 

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This is the end of lesson five. During synthesis and hydrolysis water will be split from separate molecules containing the following functional groups:(-OH and -OH), (-NH2 and -COOH), and (-OH and -COOH). This will be explained in the next lesson. Click here to go to the Miniunit Alpha Lesson Page and then continue on to lesson seven, concerning the synthesis and hydrolysis of biological polymers.  

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