A series of hydrogen ion buffers covering the pKa range 6.15-8.60. Most of these buffers are amino acids. The synthetic buffer 4-2hydroxyethyl-1-piperazineethanesulfonic acid, HEPES, has gained widespread use recently.
The preservation of animal cells in liquid nitrogen, which may be seen under biology microscopes, is now a routine practice. Damage associated with freezing has been prevented […]

With the use of biology microscopes, it can be observed that living cells maintain an internal composition very different from, but highly dependent upon, their milieu. This is due to a combination of active and passive transport. In particular, cells respond by changes in size and shape to changes in the osmotic activity of […]