What's a MICROSOME?

[Stefan Schneider]

In article <4g5m3i$gje at ds2.acs.ucalgary.ca>, ckwcheng at acs4.acs.ucalgary.ca 
says...
>
>OOPS!  I made a mistake in my posting.   I've been looking all
>over for the definition of a MICROSOME, not microbody.  Are they
>the same?
>
>I need some help.
>
>Cal

Hi,
earlier, any compartments of cells with a size at the limit of visibility 
in a normal microscope were referred to as microsomes. Today the term 
microsome means a quiet heterogenious fraction of different particles 
which is won out of decomposed cells by centrifugation.
The fraction contains besides anorganic crystals (often present in plant 
cells) sphaerosomes (spheric particles with a lipid monolayer of a size of 
about 1 micrometer), microbodies (a little smaller than the sphaerosomes 
and with a lipid bilayer membrane). The microbodies are classified by 
their biochemical function: Lysosomes containing lytic enzymes, 
Glyoxisomes with enzymes for the activation of storage-lipids and 
Peroxisomes (Katalase activity). In addition the fraction reffered to as 
microsomes contains fragments of the endoplasmatic reticulum with 
ribosomes.
I hope this helps Ciao...