Table of Contents
Macromolecule Links
Macromolecule Games
Biology Links
Honors Biology Home
Functional groups are the basis of individual function for almost all macromolecules. 
They are only add-ons to molecules, but functional groups almost completely change how a molecule is used.
Many of them even polarize the molecule they are part of, causing it to dissolve in water.
Lipids Carbohydrates
Functional groups are probably used the most in lipids of all macromolecules.  This is because, not only do the functional groups allow lipids to bond, creating fats and oils, but they make some lipids polar, and others not.  This quality defines whether or not a lipid will mix with water.  Polarization (whether a molecule has a charge or not, defining whether or not it mixes with water) such as this is used by phospholipids which are polarized lipids that form a cell membrane when placed in water. 

Fats and oils are triglycerides (one glycerol bonded with three fatty acids).  They are used as long-term energy-storage compounds in plants and animals.
The use of phospholipids is to aid the formation of cells by forming a bilayer or cellular membrane.

steroids vary in function greatly depending on their attachments.  For instance, aldosterone regulates the sodium content of the blood but testosterone, the male gender hormone that maintains male characteristics, is just one or two functional groups away.  For more on lipid structure click here!		 Carbohydrates, or sugars, are almost entirely made of funtional groups.  The functional group hydroxyl, even allows glucose to bond into a chain by the use of condensation (the joining of two similar molecules that gives off H2O, or one molecule of water).  In fact, just a few functional groups are the difference between glucose and fructose. 

Cells use carbohydrates, esecially glucose, as an immediate energy source.  Glucose is stored as starch in plants and as glycogen in animals.

In addition to energy, carbohydrates are also used in the form of chitin for cell walls.
Another function of carbohydrates is as chitin in the exoskeleton (shell) of many animals. 

Some of these animals are crabs, crawfish, and most insects.  This chitin, usually taken straight from these shells, is used for a number of things such as artificial skin, waterproof paint, and even some contact lenses!  For more on chitin click here! All types of macromolecule use functional groups.
Nucleic Acids
Proteins
Nucleic acids, being very long chains of bases, sugars, and phosphates, would not be able to form into DNA without the use of functional groups.  This is because the functional groups allow the nucleic acids to use hydrgen bonds (bonds weaker than normal because they us the attraction of hydrogen atoms), the method in which  DNA replicates. 

These hydrogen bonds also keep the DNA together until they are separated by the right enzyme (a substance that speeds ub a reaction by splitting or bonding two molecules).  For more on nucleic acid structure click here!

Nucleic acids are used mainly in cells for synthesizing protins in the cell, but DNA is also used for cellular replication because it stores the genes needed for the cell to split.
The need of functional groups.to protiens can not be stressed enough.  The protein's only part, the amino acid, relies 100% on functional groups. 

The only reason for this is that all twenty of the types of amino acids have the same exact two functional groups, a carboxyl group and an amino group.  These two groups are the only way of knowing whether or not  a molecule is an amino acid.

The sequence of amino acids determines the shape of the protein and the shape of a protein can greatly affect and determine it's function.  See amino acids bond here!

 Many proteins are ensymes that speed up chemical reactions.  The enzyme, insulin, for instance, is a hormone that regulates the glucose (a sugar) in the blood.  Hemoglobin, however, transports oxygen through the blood.
LINKS
1) a chart of functional groups
2) another chart of some of the functional groups
3) a description of some of the functional groups
Hosted by www.Geocities.ws

1