Organic Molecules

• When scientists speak about organic compounds, they are talking about molecules made of carbon--an atom that bonds to other atoms in ways that form complex three-dimensional structures. These bonds are called stable covalent bonds, which means they share electrons freely. Oxygen and hydrogen are most likely to bond with carbon, but other elements that bond to carbon include nitrogen, phosphorous, calcium, potassium, sulfur, sodium and chlorine.
  
  

Monomers and Polymers

• The smaller organic compounds--like simple sugars, fatty acids and amino acids--are called monomers. While these molecules are important, organisms often need bigger macromolecules called polymers, which are composed of many monomers joined together. The very definition of a monomer is a molecule that can be bonded to the same molecule in order to form larger ones. Reactions are catalyzed by the combination of enzymes--proteins that make substances react faster than they would on their own--and energy that the organism consumes. Enzymes can rearrange molecules, split them apart or transfer entire electrons and molecular groups.
  
  

Condensation and Hydrolysis

• Enzymes catalyze many kinds of specific monomer reactions. One reaction, condensation, splits apart an oxygen-hydrogen group from one molecule and hydrogen from the other. The exposed sites of the molecules bond to each other, and the split atoms form water as a byproduct. Another reaction known as hydrolysis does the opposite. Enzymes split a molecule apart, then use water to attach a hydroxyl group and hydrogen atom to the exposed sites.
  
  

Nucleotides and Protein Construction

• Proteins are constructed because of DNA nucleotides, which consist of two intertwining strands and four different base pairs. These base pairs are the sequences of molecules that look like rungs on a ladder. They are code for specific amino acids, which are synthesized into proteins when aligned into a sequence. Proteins often form enzymes and cell structures. They are the most fundamental of the organic molecules.
  
  

The Importance of Organic Molecules

• Organic molecules can provide structure, facilitate communication between cells, catalyze reactions and maintain energy. The assemblage of organic molecules denotes the composition of the organism. The differences between organisms are usually the differences in function that occur at the cellular level. Different enzymes and proteins will produce variations that will help an organism live and survive.