Hydrophobic and hydrophilic forces are interactions that serve to keep chemical groups positioned close to one another. Such associations are vital for the structure of the components of microorganisms.

Hydrophobic ("water hating") interactions are created because of the uncharged nature of the involved chemical groups. An example of such a chemical group is CH₃. All the bonds around the carbon atom are occupied. The chemical group is described as being nonpolar. Thus, a water molecule--a polar molecule--is unable to establish an association with the non-polar chemical group. This tends to create instability in the network of water molecules, and so is undesirable. The repulsive force of the surrounding water molecules acts to force hydrophobic regions into an association with like regions. The effect tends to be the formation of a hydrophobic "pocket" or "envelope" in a protein or a carbohydrate molecule or matrix.

Hydrophilic...