Metagenomics: Exploring the Microbial World

All the genomes listed on my page Genome Sizes describe the complete genome of a single species. For bacteria and archaeons, this means that the organism was grown in pure culture to provide the DNA for sequencing.

But it is now clear that the microbial world contains vast numbers of both groups that have never been grown in the laboratory and thus have escaped study. Soil, water, and the contents of our large intestine are examples of habitats that

ATP (Adenosine triphosphate)

ATP is a nucleotide that performs many essential roles in the cell.

  • It is the major energy currency of the cell, providing the energy for most of the energy-consuming activities of the cell.
  • It is one of the monomers used in the synthesis of RNA and, after conversion to deoxyATP (dATP), DNA.
  • It regulates many biochemical pathways.


When the third phosphate group of ATP is removed by hydrolysis, a substantial amount of free energy is released. The