Redefining Reality - The Intellectual Implications of Modern Science

Recall that cells have nuclei, and inside the nuclei are
chromosomes that contain the DNA, the instruction manual for
the entire enterprise. The DNA is in the form of a double helix
that unravels itself; in cell division, the two halves split off, and
each re-creates the other side.
As a result, we have two copies of the DNA molecules, each
of which can form the genetic material needed in the two cells
that split out of the progenitor.
At the ends of chromosomes are telomeres, which are the genetic
equivalent of hems on a pair of pants.
Every time a cell divides, the end of the chromosome gets
ripped off, leaving a series of meaningless repetitions of the
base pairs in the DNA. This is genetic code that carries no
information, making it disposable. Indeed, that is exactly its
purpose. But with each passing generation, a little bit more of
the telomere is shaved off, making it shorter.
When the telomere is gone, the meaningful genetic information
gets ripped off, making it impossible for the cell to do its
job because it no longer has the full manual. With the end of
the telomere, the cell dies, unable to replace itself through
replication. The effects of cell death in the body are the signs
we all recognize as aging.
Telomere length is affected by environment and lifestyle choices.
Smoking, emotional stress, and lack of exercise are all associated
with shortened telomeres, while regular exercise, a plant-based diet,
and stress management are associated with longer telomeres. But
even those with longer telomeres still have them shortened over
time. Aging and death work at a slower pace, but the process still
leads to an inevitable end.
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