Question

Describe why carbon is the key element in forming structural components of cells. Discuss carbons atomic structure in your answer.

Answer 1

Carbon forms four bonds in a tetrahedral arrangement around the carbon nucleus. This allows a carbon to bond to another carbon or other elements with a great variety of shapes. Links with oxygen, hydrogen, nitrogen, calcium, or phosphorus form with carbon making up the linking element between all others. Functional groups are special arrangements of atoms in a group that provide a certain type of characteristic reactivity to a molecule.

Carbon has an unparalleled ability among elements to catenate (form covalent chains of the same element). Carbon can from a chain that is linear or branched or form ring structures while also bonding with functional groups containing other elements. Another structural option in building organic molecules is carbon can form double, single or even triple bonds with another carbon.
Catenated carbon structures or catenae are the basis of organic chemistry.
http://en.wikipedia.org/wiki/Catenation

Carbon chains can alternate single and double bonds to form conjugated electron systems that absorb solar energy at specific wavelengths. These molecules function as pigments. The greater the number of conjugated multiple bonds in a molecular compound, the longer the wavelength of the light that the compound will absorb.

Chlorophyll is a very large conjugated Tetrapyrrole pigment and essential to photosynthesis and the fixation of carbon as an organic. Molecules that contain carbon bound to hydrogen are classed as organic because living organisms can further modify & use them to build other carbon based metabolic molecules.

When people say that we're carbon-based life forms, they mean that all of our important macromolecules (proteins, carbohydrates, lipids, and nucleic acids) are built using chains or rings of fixed carbon and hydrogen atoms augmented with a large number of chemical functional groups able to react.

Answer 2

yahoo answers :)
@Zebrasandsparkles914