Carbon Compounds

Element such as carbon, oxygen, phosphorus, sulfur, nitrogen and hydrogen are all important elements in making up living organisms. However, carbon is perhaps one of the most important atoms in the biological world. Of the ten million biological molecules that have been discovered carbon has been found in every single one. Carbon is special, allowing it to do more than the other atoms can, leading to a distinct variety in carbon-based molecules.

WHY IS CARBON SPECIAL?

Bonding Properties

One of the many ways that carbon is considered unique is related to its unique bonding properties, matched by no other atom. Carbon, have an atomic number of 6, has four valence electrons allowing it to form four very strong, usually covalent bonds with four other molecules. In addition carbon can form pairs of double or even triple bonds with other atoms allowing the strength of the bonds it forms in molecules to be enhanced exponentially. Another element, silicon, also has four valence electrons allowing it some of the same properties of carbon. However, it only interacts with a few other atoms, not the multitudes that carbon does. It also usually does not tend to form double and triple bonds like carbon, and forms into crystal lattice structures instead of long chains like carbon-based molecules do. In addition, silicon tends to be too large to fit together with other smaller atoms, unlike carbon, who can happily go on bonding with a multitude of other atoms.

Polarity and Shape

Carbon based molecules also come in a variety of different shapes that can also affect the polarity of the molecule. Depending on the Δ Electronegativity of the molecule, an asymmetrical shape can cause a molecule to be polar or non polar. Carbon also is a notably very stable atom, allowing little change in structure depending on the temperature. This allows carbon based molecules to not only be stable, but can allow reactivity at certain temperatures. Carbon can form long chains, with up to millions of carbons connected together. It can also form ring shaped structures and support branching, where the molecule spreads out like a tree. Its shape also allows carbon to form isomers with its different shapes, specifically three kinds, structural, geometric and optical. Structural isomers contain the same molecular formula, however they have a different molecular structure. Geometric isomers are caused due to carbons tendency to double bond with other atoms. As a result of its inflexibility, geometric isomers are formed. If the functional groups of these molecules are on the same side, they are called “Cis” isomers while if they are on opposite sides they are called “Trans” isomers. The last kind of isomer is the optical isomer. These isomers are formed if a carbon atom is attached asymmetrically to four different atoms but are mirror images of each other. These can either be Laevus, used by the cell, or Dexter, not used by the cell and perhaps are lethal to it.

Use in Functional Groups and Biomolecules

As mentioned earlier, the multitude of properties that carbon provides for molecules makes it an essential building block in biomolecules. The variation in structure, the polarity, and the interactions with other atoms all come into play when building structures such as carbohydrates, nucleic acids, proteins, and lipids, all building blocks of life.