Biochemistry

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Fifteen to twenty billion years ago, the universe arose
as a cataclysmic eruption of hot, energy-rich sub-atomic particles. Within seconds, the simplest elements (hydrogen and helium) were formed. As the universe
expanded and cooled, material condensed under the in-fluence of gravity to form stars. Some stars became enormous and then exploded as supernovae, releasing
the energy needed to fuse simpler atomic nuclei into the
more complex elements. Thus were produced, over bil-lions of years, the Earth itself and the chemical elements found on the Earth today. About four billion years ago,
life arose—simple microorganisms with the ability to ex-tract energy from organic compounds or from sunlight, which they used to make a vast array of more complex
biomolecules from the simple elements and compounds
on the Earth’s surface.
Biochemistry asks how the remarkable properties
of living organisms arise from the thousands of differ-ent lifeless biomolecules. When these molecules are iso-lated and examined individually, they conform to all the physical and chemical laws that describe the behavior

of inanimate matter—as do all the processes occurring
in living organisms. The study of biochemistry shows
how the collections of inanimate molecules that consti-tute living organisms interact to maintain and perpetu-ate life animated solely by the physical and chemical laws that govern the nonliving universe.

Yet organisms possess extraordinary attributes,
properties that distinguish them from other collections
of matter. What are these distinguishing features of liv-ing organisms? A high degree of chemical complexity and
microscopic organization. Thousands of differ-ent molecules make up a cell’s intricate internal structures (Fig. 1–1a). Each has its characteristic
sequence of subunits, its unique three-dimensional
structure, and its highly specific selection of
binding partners in the cell.
Systems for extracting, transforming, and
using energy from the...
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