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determined by a part of the genome, the stretch of DNA sequence corresponding to
this protein, located in the cell nucleus. Protein synthesis is spatially separated in
the cell and occurs in other cell formations—ribosomes. The information about the
structure to be synthesized is transferred to the ribosome by another molecule—
RNA—whose structure exactly matches to the structure of the corresponding DNA
region. The synthesis of the RNA molecule, i.e., the readout (transcription) of
information, is performed by the enzyme RNA polymerase. It splits the double-
stranded DNA molecule and uses it to synthesize a copy of the section of DNA—an
RNA molecule corresponding to the synthesized protein. This region is recognized
by the enzyme RNA polymerase using a specific label in the DNA chain—a
molecular group called the promoter. The enzyme attaches to the promoter and
starts transcription at this point of the chain. At the same time, intracellular
processes in the self-organizing system of the cell are complex and multifunctional.
In particular, the start of transcription depends on the presence or absence of
another protein, called operator. It can block the promoter, which prevents the
attachment of RNA polymerase to the DNA strand and blocks RNA transcription.
The cells of living beings are complex biological devices whose functioning is
based on a large number of biochemical reactions occurring in them. Cells spon-
taneously divide, reproducing themselves in a set of identical copies. At the same
time, the methods of cell engineering techniques developed in recent decades allow
to change the program of functioning of the cell, affecting its genetic apparatus.
This, in principle, creates the possibility to use the cells as particles of amorphous
systems that can perform complex functions such as sensor cells, actuator cells, etc.
Of substantial interest for amorphous computing is the use of cellular material
for the formation of information processing devices. One of the possibilities being
actively discussed today is the creation of cells serving as signal inverters.
It is known that cell life is ensured by constant synthesis of proteins involved in
its metabolism. The synthesis occurs in specialized cell structures—ribosomes.
Based on these mechanisms of protein synthesis in the cell, the participants in the
project “amorphous computing” G. Sussman and T. Knight proposed a biochemical
approach to the creation of digital information processing devices. It is based on the
idea of a biochemical signal inverter (Fig.
7.5
). Suppose that the protein Z is being
synthesized, with the RNA polymerase reading its structure from the corresponding
section of the DNA chain. At the same time, if there exists a protein A, which is the
operator of the process, the synthesis of protein Z may be terminated. Thus, the
system of transcription is an inverter controlled by the protein A. The authors of this
idea believe that designing interrelated chains of protein synthesis in the cell, one
can build digital logical devices of sufficiently high complexity.
The discussed possibilities of creating digital devices are the main prospective
practical applications of the principles and technology of amorphous computing
discussed in the literature today. It must be noted that in general they make an
ambiguous impression. The starting point of the concept is a distributed dynamic
system of particles. Such systems operate with a high degree of parallelism of
operations. Nevertheless, based on amorphous systems it is proposed to create
digital devices with sequential execution of operations.
