Information storage is a key component of a Turing Machine or state machine. While DNA is a long-term memory to store and transmit information over generations, short-term memories also exist within the cell. The Turing Machine formalism suggests that proteins and RNA may act as transient memory, together with other epigenetic information that is not coded in genes. Information contained in computer programs is subject to successive interpretations and translations from higher-level abstractions down to hardware instructions. In a living cell, similar computational processes can be observed at different levels of abstraction ranging from phenotype through genetic programs down to the underlying molecular interactions .
Further analogies might be useful to understand information handling in cells. In particular, the existence of a biological counterpart to Maxwell’s demon-like mechanisms could help to explain important observations in biology such as asymmetric cell division. Here, most of the damaged and old molecular components remain in the ‘mother’ cell while the ‘daughter’ receives the ‘younger’ proteins and organelles. How does the cell achieve such asymmetry during division? One hypothesis suggests that proteins are filtered by Maxwell’s demons that measure the state of encountered components – damaged or aged for instance – memorize this information, produce an action accordingly and reset their memory. Kinetic proofreading, which is an important mechanism to prevent errors during protein synthesis, can be also viewed as a process akin to Maxwell’s demon. Such arguments would stress the important role of the concept of information as a measurable quantity.
1. Condon A, Harel D, Kok NJ, Saloma A, Winfree E (2009) Algorithmic bioprocesses. Springer Science & Business Media
For an application of the Maxwell’s demon to biological problems, see:
Binder P, Danchin A (2011) Life’s demons: information and order in biology. What subcellular machines gather and process the information necessary to sustain life? EMBO Reports 12: 495-49
Computer scientist Charles Bennett compared the RNA polymerase with the read/write head of a Turing Machine and came up with considerations on energy dissipation during proofreading that shed new light on the physical dimension of the concept of information as a fifth category of Nature. For details, see:
Bennett CH (1973) Logical reversibility of computation. Ibm J Res Dev 17: 525–532
For a deeper incursion into the relationships between information and energy and the possibility to create molecular devices making use of information, see:
Serreli V, Lee CF, Kay ER, Leigh DA (2007) A molecular information ratchet. Nature 445: 523–527
Lutz E, Ciliberto S (2015) Information: from Maxwell’s demon to Landauer’s eraser. Physics Today 68: 30
About asymmetric cellular division, see:
Aguilaniu H, Gustafsson L, Rigoulet M, Nyström T (2003) Asymmetric Inheritance of Oxidatively Damaged Proteins During Cytokinesis. Science 299: 1751-1753