Biology Reference
In-Depth Information
with the sugar within the bacterium. We look at the enzymes which break down
the sugars or at the metabolic pathways, but we look at those in toto; they are
still pathways for the consumption of sugar of a certain sort within a cell. Now,
to gain enhanced insight, we may look toward more detailed descriptions of the
behavior; e.g., we might be interested in the rates at which various sugars are
consumed. As we specify the behavior more exactly, we need an explanation
of how the components function within the cell. If we think, e.g., of
E. coli
as
a set of macromolecules, we need to know what the capacities of the enzymes
are, and also how these enzymes behave
in vivo
. This is accomplished when
we refer to lower level theories, which constrain the mechanisms that belong to
higher levels of organization.
To know how the parts interact within the given system, we can compare
a variety of different systems with a similar organization and constitution. We
might, for example, compare protein synthesis in
E. coli
with protein synthesis in
a pint of beer. This would be an inappropriate comparison, given the differences
in the systems. We might also compare protein synthesis on different media or
in differing temperature regimes. An enzyme has a specific affinity for its sub-
strates, which can be assessed
in vitro
, quite apart from living organisms, which
sometimes serves as a measure of the enzyme's affinities in the living organism
(cf. Boogerd et al., 2005). This last means of analysis, if successful, would
suggest a reduction to constituent behavior in simpler systems. In Fig. 3, we
see that background theories refer to the behavior of non-interacting molecules,
which are located at a lower level of organization L
−
3.
Grades of resolution
G+1
G G-1
G-3
Example:
cellular behavior to be mechanically explained.
Level of single cells
Behavior of cells as behavior of molecular systems
Behavior of non-interacting molecules
L+1
L
L-1
L-
3
Behavior to be explained is at L
Grade of Resolution is at G-3
Parts in isolation at Grade of Resolution G-3 are at Level L-3
Figure 3
Changing levels of organization within a given grade.
We may focus, on, say, molecular details, with the aim of explaining the capacities of molecules,
or the behaviors of cells. This is clearly a change in the characteristic entities, and so a change in
the level of organization.
