Needed:Information about aging and death of organisms (human, animals)

Steve Chambers steve at
Fri Jul 7 00:41:44 EST 1995

In <AC20DB9F966833A01 at> Anne.Lilie at (Anne Lilie) writes:

Hi Anne

This is quite a shopping list of questions!  And I hope it'll stimulate 
some discussion for you.  I'll (I hope) start the ball rolling by 
answering them as succinctly as I can.

>-What exactly happens when an organism ages? 

It varies from organism to organism, and for each organism there are a
_huge_ number of changes associated with aging.

>Does the metabolism slow down,

Usually, but there's no reason for us to _assume_ that that's a bad thing.
Indeed, there are many reasons to think that a reduced metabolism may be

>and therefore reduces the intake of oxidation and water (which leads to
>hydration of the skin etc..)?
>-And why does the organism loose water (newborn 90% but adult 80%)?

I imaging that this is largely a function of increased fat %, rather than 
anything else.  However, connective tissue Xlinking and general conn. tiss.
disorder may be a factor.

>-Why do some people age later and some sooner? 

Variability in biological function is the norm - rather than the exception.

>Is the "aging clock" build in the cell?

There is certainly some form of clock in most cells which influences the
aging (or more correctly the cellular senescence) of those cells.  Whether
this has any influence on the aging of whole organisms has yet to be

>-Are all tissues (cells) affected? 

No - at least not significantly so within the lifetime of any multicellular
organisms that I'm aware of.

>Where (in which cells) does the aging process start? Or does it start 

Aging is an amalgam of many processes.  Some of them start the moment a 
cell comes into existence.  

>Are only certain tissues affected?

Effects to only some tissues have so far been shown to influence age-
dependant mortality.  

>-During the aging process, how do the molecules react and in which way do
>they change their composition?

Aging processes are many and varied.  Some of the more important "molecule
changing" agents are; reactive oxygen species and other free radicals,
glycosylation and other crosslinking reactions.

>-What is death? During the aging process have the molecules changed
>gradually,  that in the end, they just cant react anymore or very little
>with each other, and then just start falling apart (causing the organism,
>to get less and less resistant to illness...)?

>Thank you, waiting for your answers,

I've crossposted this to bionet.molbio.ageing and  Check
these newsgroups out - these matters are discussed regularly there. 


(I_lurk,_therefore_I_am!_\  ,,,                           Steve Chambers
                           (o o)          steve at

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