DNA is a pretty simple molecule when you
consider its awesome role in life. DNA
(deoxyribonucleic acid) gets its name from its
The center of every DNA molecule is a sugar
called Deoxyribose. Like other single-unit
sugars, it has 6 carbon atoms. Like all sugars I
can think of, its name ends in "ose." This
sugar ring is attached to other sugar rings by
phosphate groups to make long chains.
The reason that DNA can carry information is
because the other thing attached to the sugar is
one of 4 bases: adenine (A), thymine (T),
guanine (G), and cytosine (C). Each base
is made of different atoms, so they
interact with each other in specific ways. G
and C bond with each other and A and T bond with
each other. This makes the two chains into one
double chain that's like a ladder with the bases
as the rungs. This seems like a simple thing, but
it allows DNA to make copies of itself. That's
why DNA can be passed from one generation of cells
to the next.
Here's how it works. Suppose you
wrote "secret code" on a piece of paper, then
wrote a mirror image of each letter on another
piece of paper. If you gave the backwards copy to
a friend, he or she could make a mirror image of
each letter and be back to the original message.
If I have a string that says AATCGC, the
only bases that will line up with it will be
TTAGCG. Then when this second string is
copied, it will give me AATCGC.
To learn more:
one A lined up with a C by accident (a
"mutation"), what would happen to all future
copies of this strand of DNA?
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