Appendix B
B.1 Information Flow
When a fluctuation occurs, a local order is established and a knowledge (for example
number of particles) of this local molecular system can be performed by a device
capable to process information faster than the relaxation time of the fluctuation.
Our objective is, without entering in the mechanisms of the process, (see Refs. [1]
and [2] for possible mechanisms) the “minimum” flow of information (bits/s) a
device would have to process in order to dissipate an ionic fluctuation in the solution
through a channel within the size of a biological one; and compare this result with
some of the already existent man made devices.
In doing so we make use of the relation between the entropy production and the
information lost (bits/s) when the fluctuation is dissipating in a volume of the size
of a biological channel, of course, the device would have to process information in
a faster way in order to decide whether this fluctuation would be utilize by de cell
or not. Procopio and Fornés [3], analyzed the possibility that nature occuring ionic
fluctuation could be utilize by the cell membrane system to lead a transient ionic
flow, and to eventually produce ion concentration gradients across the membrane.
It was found that there is a broad range of concentrations for which significant
fluctuations of them take place in enclosing volumes having diameters comparable
to the membrane thickness. In these cases, the dissipation of a fluctuation close to
the membrane could result in a transient net flow of the corresponding ionic species
through the channel. In order that a channel could correlate its state of aperture to
the phase of a nearby ion density fluctuation, a flow of information is required by
the second law of thermodynamics Brillouin [4] and Bennett [1].
Molecular entities such as biological channels, “carriers”, and eventually
ATPases, may be important molecular devices for an efficient processing of
information in the form of fast conformational changes. Such structures are
in principle capable of performing the coupling of fluctuating parameters as
concentration or density to fast molecular conformational changes. Studies
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
J. A. Fornés, Principles of Brownian and Molecular Motors, Springer Series in
Biophysics 21, https://doi.org/10.1007/978-3-030-64957-9
153
B.1 Information Flow
When a fluctuation occurs, a local order is established and a knowledge (for example
number of particles) of this local molecular system can be performed by a device
capable to process information faster than the relaxation time of the fluctuation.
Our objective is, without entering in the mechanisms of the process, (see Refs. [1]
and [2] for possible mechanisms) the “minimum” flow of information (bits/s) a
device would have to process in order to dissipate an ionic fluctuation in the solution
through a channel within the size of a biological one; and compare this result with
some of the already existent man made devices.
In doing so we make use of the relation between the entropy production and the
information lost (bits/s) when the fluctuation is dissipating in a volume of the size
of a biological channel, of course, the device would have to process information in
a faster way in order to decide whether this fluctuation would be utilize by de cell
or not. Procopio and Fornés [3], analyzed the possibility that nature occuring ionic
fluctuation could be utilize by the cell membrane system to lead a transient ionic
flow, and to eventually produce ion concentration gradients across the membrane.
It was found that there is a broad range of concentrations for which significant
fluctuations of them take place in enclosing volumes having diameters comparable
to the membrane thickness. In these cases, the dissipation of a fluctuation close to
the membrane could result in a transient net flow of the corresponding ionic species
through the channel. In order that a channel could correlate its state of aperture to
the phase of a nearby ion density fluctuation, a flow of information is required by
the second law of thermodynamics Brillouin [4] and Bennett [1].
Molecular entities such as biological channels, “carriers”, and eventually
ATPases, may be important molecular devices for an efficient processing of
information in the form of fast conformational changes. Such structures are
in principle capable of performing the coupling of fluctuating parameters as
concentration or density to fast molecular conformational changes. Studies
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
J. A. Fornés, Principles of Brownian and Molecular Motors, Springer Series in
Biophysics 21, https://doi.org/10.1007/978-3-030-64957-9
153