A fun site, that is suitable for the middle school, high school, and college levels. Each of the chapters is authored by experienced educators expert in their area of presentation. The IMB Jena Image Library of Biological Macromolecules contains visual and other information on three-dimensional biopolymer structures. In addition, general information on the architecture of biopolymer structures is available. The information deposited there can be a bit overwhelming for the beginner.
Some animations are very good.
I have noticed however, some errors. This site contains a huge list of compounds. Contains structure, composition and other information regarding many compounds. A lot of information, arranged into separate set of handouts. There are no details, but good summary of what should be known.