Discontinuous system: Difference between revisions
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{{MitoPedia | {{MitoPedia | ||
|description=In a '''discontinuous system''', gradients in [[continuous system]]s are replaced by differences across the length | |description=In a '''discontinuous system''', gradients in [[continuous system]]s are replaced by differences across the length, ''l'', of the diffusion path [m], and the local concentration is replaced by the free activity, ''α'' [mol·dm<sup>-3</sup>]. The length of the diffusion path may not be constant along all diffusion pathways, and information on the diffusion paths may even be not known in a discontinuous system. In this case (''e.g.'', in most treatments of the [[protonmotive force]]) the diffusion path is moved from the (ergodynamic) isomorphic force term to the (kinetic) [[mobility]] term. The ''synonym'' of a discontinuous system is '''compartmental system'''. In the first part of the definition of discontinuous system, three compartments are involved (the source compartment A, the internal boundary compartment with thickness ''l'', the sink compartment B). In a two-compartmental description, the thickness of the internal boundary comparment (''e.g.'', a semipermeable membrane) is reduced to a theoretical zero thickness. Similarly, the intermediary steps in a chemical reaction may be explicitely considered in an ergodnamic multi-comparment system; alternatively, the kinetic analysis of all intermediary steps may be collectively considered in the catalytic reaction ''mobility'', reducing the measurement to a two-compartmental analysis of the substrate and product compartments. | ||
|info=[[Force]] | |info=[[Force]] | ||
}} | }} | ||
== Compartmental description of diffusion (d): vectorial flux and force in a discontinuous system == | |||
''Work in progress'' | |||
::: '''Three compartments''' | |||
::::* ''J''<sub>d</sub> = -''u''·''α''·Δ<sub>d</sub>''F'' = -''u''·Δ<sub>d</sub>''Π''/''l'' | |||
::::::::* ''F''<sub>d</sub> = Δ''μ''/''l'' | |||
::::::::* ''α''·Δ''μ'' = ''RT·Δ''c'' | |||
::::* Free activity: ''α'' = ''RT''·Δ''c''/Δ''μ'' = Δ''c''/Δln''c'' (Gnaiger 1989) | |||
::: '''Two compartments''' | |||
::::* ''J''<sub>d</sub> = -''b''·''α''·Δ<sub>d</sub>''F'' = -''b''·Δ<sub>d</sub>''Π'' | |||
::::::::* ''F''<sub>d</sub> = Δ''μ'' | |||
::::::::* ''α''·Δ''μ'' = ''RT·Δ''c'' | |||
::::* Free activity: ''α'' = ''RT''·Δ''c''/Δ''μ'' = Δ''c''/Δln''c'' (Gnaiger 1989) | |||
{{MitoPedia concepts | {{MitoPedia concepts | ||
|mitopedia concept=Ergodynamics | |mitopedia concept=Ergodynamics | ||
}} | }} | ||
Revision as of 00:58, 18 September 2018
Description
In a discontinuous system, gradients in continuous systems are replaced by differences across the length, l, of the diffusion path [m], and the local concentration is replaced by the free activity, α [mol·dm-3]. The length of the diffusion path may not be constant along all diffusion pathways, and information on the diffusion paths may even be not known in a discontinuous system. In this case (e.g., in most treatments of the protonmotive force) the diffusion path is moved from the (ergodynamic) isomorphic force term to the (kinetic) mobility term. The synonym of a discontinuous system is compartmental system. In the first part of the definition of discontinuous system, three compartments are involved (the source compartment A, the internal boundary compartment with thickness l, the sink compartment B). In a two-compartmental description, the thickness of the internal boundary comparment (e.g., a semipermeable membrane) is reduced to a theoretical zero thickness. Similarly, the intermediary steps in a chemical reaction may be explicitely considered in an ergodnamic multi-comparment system; alternatively, the kinetic analysis of all intermediary steps may be collectively considered in the catalytic reaction mobility, reducing the measurement to a two-compartmental analysis of the substrate and product compartments.
Reference: Force
Compartmental description of diffusion (d): vectorial flux and force in a discontinuous system
Work in progress
- Three compartments
- Jd = -u·α·ΔdF = -u·ΔdΠ/l
- Fd = Δμ/l
- α·Δμ = RT·Δc
- Free activity: α = RT·Δc/Δμ = Δc/Δlnc (Gnaiger 1989)
- Three compartments
- Two compartments
- Jd = -b·α·ΔdF = -b·ΔdΠ
- Fd = Δμ
- α·Δμ = RT·Δc
- Free activity: α = RT·Δc/Δμ = Δc/Δlnc (Gnaiger 1989)
- Two compartments
MitoPedia concepts:
Ergodynamics