Biochemistry http://www.queenoflub.com/biochem/
Explanations, with images and animations, covering the basics of biochememistry. Written by a high school, ex-AP Biology and AP Chemistry student.
Cell Fractionation http://www.freewebs.com/ltaing/
About the methods used to separate the organelles and components of a cell. With pictures and a description of homogenization and centrifugation.
Cells Are Us http://peer.tamu.edu/curriculum_modules/Cell_Biology/index.htm
Middle school online curriculum about cells. The five units include: levels of organization, interacting with the outside world, creating energy for the cell, coding and translating instructions, and making protein machinery do things. Offers notes and graphics.