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| Carbon
atom |
The Building Block
of Life: the "Carbon" Atom
Carbon is the most vital element
for living beings, because all living organisms
are constructed from compounds of carbon. Numerous
pages would not be enough to describe the properties
of the carbon atom, which is extremely important
for our existence. Nor has the science of chemistry
yet been able to discover all of its properties.
Here we will mention only a few of the very
important properties of carbon.
Structures as diverse as the
cell membrane, the horns of an elk, the trunk
of a redwood, the lens of the eye, and the venom
of a spider are composed of carbon compounds.
Carbon, combined with hydrogen, oxygen, and
nitrogen in many different quantities and geometric
arrangements, results in a vast assortment of
materials with vastly different properties.
So, what is the reason for carbon's ability
to form approximately 1.7 million compounds?
One of the most significant
properties of carbon is its ability to form
chains very easily by lining carbon atoms up
one after another. The shortest carbon chain
is made up of two carbon atoms. Despite the
unavailability of an exact figure on the number
of carbons that make up the longest carbon chain,
we can talk about a chain with seventy links.
If we consider that the atom that can form the
longest chain after the carbon atom is the silicon
atom forming six links, the exceptional position
of the carbon atom will be better understood.1
Diamond, which is a very valuable stone,
is a derivative of carbon, which is otherwise
commonly found in nature as graphite.
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The reason for carbon's ability to form chains
with so many links is because its chains are not
exclusively linear. Chains may be branched, as
they may also form polygons.
At this point, the form of the chain plays a
very important role. In two carbon compounds,
for example, if the carbon atoms are the same
in number yet combined in different forms of chains,
two different substances are formed. The abovementioned
characteristics of the carbon atom produce molecules
that are critical for life.
Some carbon compounds' molecules consist of just
a few atoms; others contain thousands or even
millions. Also, no other element is as versatile
as carbon in forming molecules with such durability
and stability. To quote David Burnie in his book
Life:
Carbon is a very unusual element. Without the
presence of carbon and its unusual properties,
it is unlikely that there would be life on Earth.2
Concerning the importance of carbon for living
beings, the British chemist Nevil Sidgwick writes
in Chemical Elements and Their Compounds:
Carbon is unique among the elements in the number
and variety of the compounds which it can form.
Over a quarter of a million have already been
isolated and described, but this gives a very
imperfect idea of its powers, since it is the
basis of all forms of living matter. 3
The class of compounds formed exclusively from
carbon and hydrogen are called "hydrocarbons".
This is a huge family of compounds that include
natural gas, liquid petroleum, kerosene, and lubricating
oils. The hydrocarbons ethylene and propylene
form the basis of the petrochemical industry.
Hydrocarbons like benzene, toluene, and turpentine
are familiar to anyone who's worked with paints.
The naphthalene that protects our clothes from
moths is another hydrocarbon. Hydrocarbons combined
with chlorine or fluorine form anaesthetics, the
chemicals used in fire extinguishers and the Freons
used in refrigeration.
As the chemist Sidgwick stated above, the human
mind is insufficient to fully understand the potential
of this atom that has only six protons, six neutrons
and six electrons. It is impossible for even a
single property of this atom, which is vital for
life, to form by chance. The carbon atom, like
everything else, has been created by Allah perfectly
adapted for the bodies of living beings, which
Allah encompasses down to their very atoms.
What is in the heavens and in the earth belongs
to Allah. Allah encompasses all things. (Surat
an-Nisa': 126)
Intermolecular
Bonds:Weak Bonds
The bonds combining
the atoms in molecules are much stronger than
these weak intermolecular bonds. These bonds can
help the formation of millions, and even billions
of kinds of molecules.
Well, how do
molecules combine to form matter?
Since molecules
become stable after their formation, they no longer
swap atoms.
So, what holds them together?
In an effort to answer this question, chemists
produced different theories. Research showed that
molecules are able to combine in different ways
depending on the properties of the atoms in their
composition.
These bonds are very important for organic chemistry,
which is the chemistry of living beings, because
the most important molecules constituting life
are formed due to their ability to form these
bonds. Let us take the example of proteins. The
complex three-dimensional shapes of proteins,
which are the building blocks of living things,
are formed thanks to these bonds. This means that
the weak chemical bond between molecules is at
least as necessary as the strong chemical bond
between atoms for the formation of life. Certainly,
the strength of these bonds must be of a certain
measure.
We can continue with the protein example. Molecules
called amino acids combine to form proteins, which
are much larger molecules. The atoms forming amino
acids are combined by covalent bonds. Weak bonds
combine these amino acids in such a way as to
produce three-dimensional patterns. Proteins can
function in living organisms only if they have
these three dimensional patterns. Therefore, if
these bonds did not exist, neither would the proteins,
or, therefore, life exist.
The "hydrogen" bond, a type of weak
bond, plays a major role in the formation of materials
that bear great importance in our lives. For instance,
the molecules forming water, which is the basis
of life, are combined by hydrogen bonds.
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