Natural Science Forum / Biology / Microbiology / December 2004

Umm... do you have any citations indicating that chemistry is different?

I agree with Al here... with regard to chemistry, there is nothing
special about life. It's all just chemistry.

No no no ... physics is a special case of chemistry :) :)

Bruce

------------------------------
Health nuts are going to feel stupid someday, lying in hospitals
dying of nothing.

-Redd Foxx

Caution ===== followups may have been changed to relevant groups
(if there were any)

This is exactly the reason why people tend to turn to gods.

What you must understand is that life isn't created on a daily basis.
Life is continuous. The sperm and egg is alive, and the zygote is
living; when it eventually transforms into a baby it's just a matter of
growth, not going from unliving to living. There aren't really
mysterious forces in play here, it's just a matter of utilizing (with
enzymes) the atoms in food to create the molecules that make up our
cells. The mechanics is well-known and characterized, but it is still
amazing, especially as you start to really dive deep into it, but it's
never so amazing that you have to create divine beings to answer it.

Yes. The atoms are the same, the molecules, however, are not. Two
different molecules made up of the same atoms can have completely
different properties. Our basic set of atoms can in theory create an
infinite number of different molecules all with different properties. We
could even break it further down, passed the atoms down to protons and
electrons and whatever. The amount of components is lowered even
further, but they can all be arranged in a much larger repertoire to
make up our arsenal of atoms.

I don't understand this sentence. But I can comment on parts of it.
First of all, let's not use the words miraculous and cosmic. There is
nothing miraculous going on, and cosmos has really nothing to do with
it. The bonds between atoms and molecules are well-defined and
characterized, so it's inappropriate to call them mysterious. The
evolution from inert matter to catalytic organic molecules to what we
could define as living cells, is intricate and not fully understood. But
there are no steps that circumvent our understanding of chemistry.

The cell cycle is well understood. We know the basics in why a cell
divides. and how a differentiated multicellular organism develops.
Please pick up a molecular biology book.

The complexity is not infinite, but it's way beyond our ability to
precisely describe any organism in the most intricate detail
(positioning of every atom and so forth). What we do, though, is focus
on certain phenomena, e.g. cell division, and when this is basically
understood, we cross-link it to other phenomena and thereby gain an
integrated model.

Trond Erik

Google "mitogenetic radiation".

http://www.21stcenturysciencetech.com/articles/mitogenetic.html

There is no mysterious force. It's too complex to write out here -
there's many textbooks on the topic. The single cell divides into two,
and they divide into four. Cells divide, and as they do they begin to
differentiate into sligthly different cells depending on various
chemical signals they recieve (or dont recieve). This causes expression
of different genes and their products are proteins which carry out
different functions in the cells. Hence the different cells play
different roles, and form all the parts of the body that are required to
give the function that you see in the child (and adult)

What is the question? You need to keep going down in scale. Organism, to
cell, to organelle, to cellular components like enzymes, to the
molecules that make up the enzymes. I really think you need to
understand how enzymes carry out biological reactions to help facilitate
the construction of cellular components, the production of energy, etc.
Also, learn about energy flow in biological systems, and that enzymes
help facilitate reactions that would not normally occur because they are
energetically unfavourable. This is one difference between living and
non-living things. Cellular reproduction, when you look closely enough,
is just a complex biochemical reaction. Perhaps you should choose a
small component of the activities of a cell, and follow it through to
the smallest detail we have available.

PS: Write an email to the molecular biology company 'Roche' and ask them
for the Biochemical Pathways posters... they'll send them to you for
free, and you'll see a small summary of some of the molecules that are
transformed from one to the other for use in the cell and some ezymes
that carry out the process (:

Yes, that's right. But that "mainly" is important - there's many other
elements in there as well, but not nearly as much. For example, the
protein 'haemoglobin' in your blood cells contains iron atoms. All
proteins are made up of long strings of amino acids all covalently
joined together, and every cysteine amino acid, for example, contain a
suphur atom. The cellular instructions, DNA, is joined together by
phosphorus atoms etc.

Yes, but they dont come together spontaneously. There are enzymes in the
body, and spontaneous chemical reactions, that assemble them to form
very specific substances. For example, the enzyme DNA polymerase is a
protein which is folded up in such a way that it can 'manufacture' DNA.
It takes single nucleotides (relatively simple small chemicals) and
links them together to create DNA. That piece of plastic you were
talking about forms from the same atoms, but not the same molecules.
This question of yours indicates to me that you also need to do some
reading on the difference between atoms and molecules, and how molecules
are formed from the atoms (by this, I do not mean how the atoms are
physically placed in the molecule and what bond types hold them there
but how they actually come to be there in the first place). You need to
differentiate between atomic structure and molecular structure.

I'm not completely sure what you mean here... but i'll have a guess (:

DNA is also non-living. All molecules in the body are non living.
Realise that there's nothing really 'mystical' about 'life'.
Scientifically, it's just an word that we have used to describe a
phenomenon that has been observed. Once you go below the level of the
cell (or maybe organelle if you're not a microbiologist!), certainly to
the molecular level anyway, I'm not sure that 'life' has any meaning
anymore. Just complex biochemical reactions.

The reason that the cell divides is already understood. You dont need a
microscope to see it. It is not something to do with the atoms. Once
again, it's the particular set of biochemical reactions that occur
inside the cell that cause it to happen.

Certainly not infinite. Just quite complicated. But you only need to
consider a single cell to examine life. Even more simply you can study a
single bacterium. Complex life forms are just large groups of these
cells working together and performing different roles that all aid one
another somehow.

Maybe, but who knows what the future may hold. (: We can certainly store
frozen single cells for a long time (:

PS: Just to get you thinking even further... Having started to consider
what it is that causes 'life', now you might like to examine the science
behind ageing and death. This is just as interesting a topic, and is
still far from being understood (:

Scott.

You're complicating the problem by oversimplifying it.  You don't
start
with a single cell and get a baby.  You start with a single cell, and
feed it complex organic molecules, in a conditioned environment, for
nine months, to get a baby.  That single cell isn't a sudden
development.  It's the cumulative effect of simpler forms.

Similarly, life didn't spring from some inorganic molecules one warm
spring day.  It's been building on self-replicating, carbon-based
molecules over a very long time.  There is no one split-second, before
which, everything was water, salt and minerals, and after which was a
simple life form.  Likewise, simple organic molecules are the building
blocks, over the long-term (eveolving into life forms) and the
short-term (what'd you eat today), of larger complex
living things.

The replication of DNA, and the catalysis of proteins are a bit more
dependant on weaker chemical bonds (hydrogen bonding, van der waals)
than the ionic and covalent bonds of inorganic chemistry.  That's part
of the limitations of describing life entirely as a chemical process,
living things work within a limited range of conditions, outside of
which, the reactions fail, and the living thing dies.  You can't
reverse the "death reaction" because another living thing starts
rotting the carcass -- before the brain even dies.

Chemistry is the same in industry or living things, but when industry
wants fixed nitrogen, it uses platinum and pressure -- not a vat of
legume nodules.

Oh, one last thing for the divine watchmaker crowd -- if someone
offered me a camera designed and manufactured like the vertebrate eye,
I'd send it back.  Life is as magical as Santa Claus stories -- you
have to have them both, but no one can explain why.

You may have intended that just to be colorful. But I also worry that
it is making the matter difficult for you. Humans are not infinitely
complex. They are only slightly more complex than somewhat simpler
organisms.

The cellular development of a worm can be described in great detail.
The molecular basis of some of the development of a fly can be
described in great detail. And we have at most 2-fold more genes than
either of those, and perhaps 10-100 fold more proteins. Virtually all
this understanding, and certainly all of it at the molecular level,
has come within recent decades, so it should not be surprising that
the understanding is incomplete. Further, doing this kind of research
on humans, or even on primates, is discouraged -- and is slow in the
limited cases where it can be done.

Another important issue is to realize how imperfect some of the
processes are that we often think about, even take for granted. Some
major percentage of fertilized eggs fail to develop, because they are
defective. Still, a small but significant percentage are born with
defects. At the molecular level, it is thought that something like a
third of the proteins we make are defective. When you realize these
things, and realize that they follow from the imperfections of
molecular interactions, you have a better perspective.

If you want to understand development and life processes, study
biology -- in detail. There are huge amounts of info out there, with
more coming in. It can take pages or even a book to explain one step.
One cannot answer how life develops in short messages.

bob

Yes, that's the problem! We all have to choose a definition... I
certainly don't regard viruses, virions, viroids or prions as 'alive',
and that's why my definition includes metabolism (:

Scott.

Uhmmmm, let's examine this closely,

1.  You allegedly can't find two of my
letters supporting my charge upon accepted
science.

2.  You apparently don't have credentials
you're proud of.

3.  I'm not advancing any theory, new or not.

4.  And, you're queer, aren't you (otherwise,
do you claim extraterresterial beings are
controlling your brain?)?

 Mark (It's not _me_;, it's _them_  :-)