Information Technology Reference
In-Depth Information
(Define-growing-point (make-red-branch length)
(Material red-stuff)
(Sixe 5)
(Tropism (and (away-from red-pheromone)
(And (keep-constant pheromone-1)
(Keep-constant pheromone-2))))
(Avoids green-pheromone)
(Actions
(Secrete 2 red-pheromone)
(When ((<length 1)
(Terminate))
(Default)
(Propagate (- length 1) )))))
In this program the starting growing point is referred to as “red.” Throughout the
process determined by the program, a new branch of red particles (material red
stuff) must be grown. The direction along which the branch grows is determined by
tropism—the repulsion from the red starting point, the repulsion from the top
(pheromon1), and the repulsion from the bottom (pheromon2) backbone, which
are assumed to have already been formed.
The same principle governs the formation of the remaining elements of the
inverter, as shown in Fig.
7.2
. On the basis of inverter circuits various logical
devices can be created. Therefore, the authors of the concept believe that the
technology of amorphous computing can be effectively used for the development
of information processing devices based on industrially produced particles with the
desired properties.
At the same time, the authors of the concept lay the greatest hopes on the
symbiosis between the ideas of amorphous computing and cell engineering.
7.1.1 Some Details
Genetic information that determines the structure, function, and evolutionary path-
ways of a living organism is encoded in the molecules of the deoxyribonucleic acid,
DNA, which are located in the nuclei of cells. The basis of the DNA molecule is a
polymer chain with alternating groups of phosphoric acid and a sugar—deoxyri-
bose (Fig.
7.3
). In view of the structural features of these molecular groups (i.e., the
values of angles between the bonds of the atoms within them), these polymer chains
form helical structures. Attached to each ribose group is one of the four nitrogenous
bases: adenine (A), thymine (T), guanine (G), or cytosine (C). In general, the group
consisting of the phosphoric acid residue, deoxyribose, and the base is called
nucleotide. A remarkable property of these bases is that by means of hydrogen
bonds, the pairs A-T and G-C can form stable groups whose sizes along one of the
axes are surprisingly similar (Fig.
7.4
). Therefore, these pairs form bridges that
connect the strands of DNA into a stable double helix. The A-T and G-C pairs and
the structures based upon them are called complementary. During reproduction
(replication) of DNA molecules the double helix unfolds and the molecule of the
enzyme DNA polymerase attaches to each strand. This enzyme determines the type
