Functional Groups

 Functional groups are groups of organic molecules that react in predictable ways  We use them to understand biochemical reactions between carbohydrates, fatty acids, proteins and nucleic acids

Condensation reactions - dehydration synthesis  Take a look at the reaction drawn here  Name the functional groups involved  This is a reaction that bonds two glucose molecules together and produces maltose and water

Dehydration synthesis between two hydroxyl groups  Hydroxyl groups characterize alcohols and sugars  They are polar and participate in the the synthesis reactions that build starches from simple sugars  This diagram continues where the previous one left off - the synthesis of maltose from two glucose molecules

Dehydration synthesis of sucrose  In this example, one glucose is replaced with fructose  The reaction is the same though, because the functional groups are both hydroxyl - like the 2 glucose molecules

Carbonyl groups  Carbonyl groups are also polar  They can be found at the end of the carbon chain, or in the middle  They are characteristic groups in ketones and aldehydes  Simple sugars contain polar carbonyl groups - they are either ketose sugars (fructose) or aldose sugars (glucose)

Carboxyl Groups  These polar groups are characteristic of organic acids  They are particularly important to fatty acids - the long carbon chains are unreactive and non- polar, but dehydration synthesis reactions can occur at the functional group end

Amino Groups  Amino groups are basic and polar and characterize amino acids, the building blocks of protein  What is the second functional group that characterizes amino acids?

Amino acids and peptide bonds  These two groups are critically important in the formation of proteins  Peptide bonds form between the two functional groups - another example of dehydration synthesis

Phosphate groups and sulfhydryl groups  Phosphate groups are responsible for bonding with hydroxyl groups in the backbone of DNA molecules  Sulfhydryl groups react with each other, forming covalent bonds in proteins