Scale: 10^-9 meters = 1 nm = 1 nanometer

The Structure of DNA

The central molecule in this image represents the carbon tetrahedral bond. Since the carbon atom has four electrons in its outer shell, it can form bonds with four other atoms or molecules, including other carbon atoms. The ability of carbon to form long chains and rings provides the molecular complexity required for life.

The carbon bond is so important to life that chemistry is divided into two branches, organic and inorganic. Organic chemistry is the branch of chemistry devoted to carbon-hydrogen molecules – the chemistry of life. The image represents a portion of a molecule of DNA. One complete coil of DNA is about 3 nm in length and about 1 nm wide. Genes and chromosomes are the blueprint of all life on earth and are made up long strands of DNA.