Page 100 - The Miracle in the Cell

THE MIRACLE IN THE CELL
Enzymes

Many complex events take place in our bodies every second. So
detailed are they, that at every step, their complex reactions need to be
regulated by super overseers to bring about order: the enzymes. In every
living cell, hundreds of enzymes are found, each with its own special
duty: breakdown of nutrients, production of energy from nutrients,
production of macromolecular chains from simple molecules, and
innumerable other similar processes.
Enzymes play a vital role in all cellular functions, from protein
synthesis to energy production. If not for these enzymes, not one of
your bodily functions, from the simplest to the most complex, would
operate; or else they would slow down and stop altogether. You would
not be able to breathe, eat or digest anything, see, or speak. The result
in either case would be death.
We can compare enzymes' speeding-up of body processes to an
example from everyday life. The few seconds' time it takes to read a
sentence under normal circumstances would, without any enzymes,
take ten years. The enzymes that play a role in bodily reactions are at
least as rapid as this example.
The relationship between an enzyme and the substance it affects
is like that between a lock and key. An enzyme and the substance it
binds to, join together in a complex three-dimensional manner (see
Figure 5.3). Each has been created to fit the other in the most appro-
priate ways (see Figure 5.4). What's more, this harmony comes about
at a speed so dizzying that in one second, one enzyme can bind to 300
substances, one after the after, changing each one into the desired form
and then separating from it (see Figure 5.5).
In short, cells live thanks to enzymes, and each cell produces the
enzymes it needs for itself, in the required amounts.
All of this should cause an intelligent person to ask how it is that
a cell can tell when a substance is needed and calculate its require-
ments? Does the cell itself design these enzymes that work faster than

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