Information flow, biological systems

The major direction of information flow in biological systems is from DNA to RNA to protein. However, there are instances in which RNA is copied into a complementary DNA strand by the process dubbed reverse transcription by the enzyme known as the reverse transcriptase . This mechanism is used by retroviruses including the HIV virus, whose infectious particles contain RNA as the genetic material. The virus particles contain a virally encoded reverse transcriptase which, following infection, copies the viral RNA into DNA. The resultant DNA copy is incorporated into the genome of the infected cell. 

According to the central dogma of molecular biology, the flow of information in living systems is summarized by the sequence... 

To obtain as complete a picture as possible of the kinetics, it is important to obtain a maximum time resolution. Many biological reactions occur in a very short time (in fact, down to picoseconds in vision and photosynthesis) so that slower, more traditional techniques such as stopped-flow often lack adequate time resolution. Under fortunate circumstances where the system studied is photosensitive, or where the free-energy change between reactants and products is sufficiently small, then the concentrated energy impulse from a laser is a marvelous tool that can provide a wealth of information concerning the system. The intent of the review is not to offer an exhaustive review of the literature, which would be an overwhelming task. Rather we hope to delineate areas where lasers have played an important role, to discuss the importance of these investigations, and to point to areas where their potential is still untapped. 

Information Flow in Biological Systems Classes of RNA Molecules Transcription Post-transcriptional... 

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