2006-07-26 04:34:45 · 2 answers · asked by Ngozika N 1 in Science & Mathematics ➔ Biology
If you apply a method of chemical fixation and your fixative contains alcohol, you have to expect visible deformities due to severe shrinkage caused by cell dehydration. A 10 to 30% decrease of overall size is not unusual! If your fixative contains heavy metal ions such as zinc (Zn2+) or mercury (Hg2+) they may coagulate and precipitate proteins in granular form. Tannin, arsenic, detergents and acids may be components of a fixative (especially in the formulae of the good old days!) and their deleterious effects depend on the concentration and the duration of the fixation. Nevertheless, many still prove to be very useful and even unique in some specific conditions. For example, osmic acid (OsO4) is a perfect fixative for fatty substances and is preferred as a secondary fixative of samples for electron microscopy. Unfortunately osmic acid and some other fixatives are extremely toxic and should only be accessible and safely used in professional laboratories.
2006-07-26 06:09:47 · answer #1 · answered by yason 2 · 0⤊ 0⤋
You fall over and laugh a lot!
2006-07-26 11:38:10 · answer #2 · answered by TAFF 6 · 0⤊ 0⤋