Search PubMed⌕ Search

Biomedical subjects

A V Melkikh

Publications and source records attributed to A V Melkikh.

8 recordsLinked to original sources
PubMed2006

Requirements on models and models of active transport of ions in biomembranes.

Requirements on models of the active transport of ions in biomembranes have been formulated. The basic requirements include an explicit dependence of the resting potential and intracellular concentrations of ions on the difference of ATP-ADP chemical potentials, a consideration of the reversibility of the ionic pump operation, a correlation between theoretical and experimental data on the resting potential and intracellular concentrations of ions for different types of cells, the pump efficiency approaching 100%, and a tendency of the resting potential to the Donnan potential if the active transport is blocked. A model satisfying the aforementioned requirements has been proposed by the authors as an example.

Adenosine Diphosphate↗
PubMedDate not supplied

[On the mechanism of generation of electrical potential differences in cell biomembranes].

A statistical model of active ion transport in biomembranes was developed. The model makes it possible to calculate both the value of membrane potential phi zero and the rate of ion concentrations inside and outside the cell. These values depend on the difference of chemical potentials of the ATP-ADP system and the permeability of the biomembrane for ions being transported. The calculated phi zero value approximately 200-250 mV is consistent with the data on proton pumps.

Adenosine Diphosphate↗
PubMedDate not supplied

[Model for the cell biomembrane electric potential during active transport of various ions].

A model of a stationary electrical potential on biomembrane was created. This model takes into account conformational changes in transport ATPase. N positive ions are transported simultaneously by the system of active transport. The model allows one to determine independently ion concentrations inside the cell and membrane electrical potential. It is shown that, to obtain the electrical potential, it is necessary to take into account organic negative intracellular ions. The effect of positive ions that are not transported by active transport systems on the potential value is discussed. The results obtained are in a good agreement with experimental data for various cells.

Algorithms↗
PubMedDate not supplied

[Can an organism select new valuable information from environment].

The process of selecting new information by the organism ("learning") was studied. To take a decision, key patterns have to be set a priori, and so knowledge accumulation (learning) based on pattern recognition is impossible. It was shown that the only physical process that, takes place during the emergence of an external signal is the triggering of a priori programmes. An equivalent biophysical scheme of pattern recognition and taking the decisions by the organism was developed in which a signal received by the receptor leads to the synthesis of one of possible catalysts. The catalyst starts up the corresponding thermodynamic process. The information contained in the organism does not change during this process.

Animals↗
PubMedDate not supplied

[Could life evolve by random mutations?].

The problem of the rate and mechanisms of evolution was considered. It was shown that organisms could not be formed by random mutations during real times of about one million years. It was concluded that deterministic models are necessary for the description of evolution.

Evolution, Molecular↗
PubMedDate not supplied

[Effectiveness of energy transformation during active transport of ions in a biomembrane].

A statistical model of active ion transport in biomembrane is presented. The coefficient of energy conversion for linear and nonlinear processes in this system is obtained. It is shown that in the linear case this coefficient equals to the one obtained in linear thermodynamics. Based on the maximum of this coefficient, the transport parameters for ions are found. The results of the statistical model are in good agreement with experiments on biological membranes.

Adenosine Triphosphate↗
PubMedDate not supplied

[Conformational mechanism for transforming energy during active ion transport in a biological membrane].

A statistical model of active transport of ions in the biomembrane is presented. The coefficient of energy conversion for linear and non-linear processes in this system is obtained. It is shown that in the linear case this coefficient is equal to that obtained in linear thermodynamics. On the basis of the maximum of this coefficient transport parameters for ions are found. The results of the statistical model are in a good agreement with the experiments on the biological membranes.

Biological Transport, Active↗