Atom Gallery

HIV reverse transcription enzyme

HIV reverse transcription enzyme. Molecular models of the reverse transcriptase enzyme found in HIV (the human immunodeficiency virus). The foreground model shows the helices and arrowed sheets representing the enzyme's shape (secondary structure). The background model shows the 7844 atoms (spheres) of the molecular structure. Reverse transcriptase is an enzyme that is a key part of the process of producing DNA (deoxyribonucleic acid) from the instructions contained in a strand of RNA (ribonucleic acid). Many viruses, including HIV, consist of a core of RNA, and this reverse transcription is how HIV infects human cells. This enzyme is from the HIV-1 form of HIV, the virus that causes AIDS (acquired immune deficiency syndrome)

© LAGUNA DESIGN/SCIENCE PHOTO LIBRARY

Bose-Einstein condensate simulation

Bose-Einstein condensate simulation. Computer simulation of vortices forming within a spinning Bose-Einstein condensate (BEC). A BEC is a state of matter that can arise at very low temperatures. Atoms are trapped using laser beams and magnets, and supercooled almost to absolute zero. At these temperatures, the atoms all have the same quantum energy state, and are indistinguishable. They coalesce, behaving as if they were one single super atom. During the process, two laser beams are rotated rapidly around each other, causing a stirring action that generates vortices in the atom cluster and facilitates the formation of the condensate. This simulation helped to confirm that BEC's are superfluids - a kind of liquid/gas that flows without friction

© NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY/SCIENCE PHOTO LIBRARY

Molecular orbitals

Molecular orbitals. Computer model of a mixture of molecular orbitals. The electrons in molecules can be arranged in different patterns, giving rise to different energies. These patterns, or molecular orbitals, can co-exist within the rules of quantum mechanics. This leads to the concept of mixing the molecular orbitals to model the overall behaviour of the molecule. This mixing is seen here as the overlapping mix of colours and lines of potential energy surface. This pattern is an example of caustics, the patterns arising when overlap is observed. This model was created as an artwork by Professor Eric Heller

© ERIC HELLER/SCIENCE PHOTO LIBRARY