The Architecture of Life
A universal set of building rules seems to guide
the design of organic structures, from simple
carbon compounds to complex cells and tissues
by Donald E. Ingber
Life is the ultimate example of complexity at work.
An organism, whether it is a bacterium or a baboon, develops
through an incredibly complex series of interactions involving
a vast number of different components. These components, or
subsystems, are themselves made up of smaller molecular
components, which independently ex- hibit their own dynamic
behavior, such as the ability to catalyze chemical reactions.
Yet when they are combined into some larger functioning units
such as a cell or tissue—utterly new and unpredictable properties
emerge, including the ability to move, to change shape and to grow.
Although researchers have recognized this intriguing fact
for some time, most discount it in their quest to explain life's
fundamentals. For the past several decades, biologists have
attempted to advance our understanding of how the human body
works by defining the properties of life it's critical materials
and molecules, such as DNA, the stuff of genes. Indeed, biologists
are now striving to identify every gene in the complete set, known
as the genome, that every human being carries. Because genes are
the blueprints for the key molecules of life, such as proteins, this Holy
Grail of molecular biology will lead in the near future to a catalogue of
essentially all the molecules from which a human is created.
Understanding what the parts of a complex machine are made of,
however, does little to explain how the whole system works, regardless
of whether the complex system is a combustion engine or a cell. In other
words, identifying and describing the molecular puzzle pieces will do little
if we do not understand the rules for their assembly.
That nature applies common assembly rules is implied by the
recurrence at scales from the molecular to the macroscopic
of certain patterns, such as spirals, pentagons and triangulated
forms. These patterns appear in structures ranging from highly
regular crystals to relatively irregular proteins and in organisms
as diverse as viruses, plankton and humans. After all, both organic
and inorganic matter are made of the same building blocks: atoms of
carbon, hydrogen, oxygen, nitrogen and phosphorus. The only
difference is how the atoms are arranged in three-dimensional space.
This phenomenon, in which components join together to form larger,
stable structures having new properties that could not have been
predicted from the characteristics of their individual parts, is
known as self-assembly. It is observed at many scales in nature.
In the human body, for example, large molecules self-assemble into
cellular components known as organelles, which self-assemble into
cells, which self-assemble into tissues, which self-assemble into
organs. The result is a body organized hierarchically as tiers of
systems within systems. Thus, if we are to understand fully the
way living creatures form and function, we need to uncover these
basic principles that guide biological organization.
Despite centuries of study, researchers still know relatively little
about the forces that guide atoms to self-assemble into molecules.
They know even less about how groups of molecules join together to
create living cells and tissues. Over the past two decades, however,
I have discovered and explored an intriguing and seemingly fundamental
aspect of self-as-sembly. An astoundingly wide variety of natural
systems, including carbon atoms, water molecules, proteins,
viruses, cells, tissues and even humans and other living creatures,
are constructed using a common form of architecture known as tensegrity.
The term refers to a system that stabilizes itself mechanically because
of the way in which tensional and compressive forces are distributed and
balanced within the structure.
http://www.childrenshospital.org/resear ... Ingber.pdf