- high-resolution terminology - matching measurements at high-resolution
Discontinuous system
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, spacial direction varies (e.g., in a spherical particle surrounded by a semipermeable membrane), 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 systems, three compartments are considered: (1) the source compartment A, (2) the sink compartment B, and (3) the internal boundary compartment with thickness l. 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
- Force: ΔdF = Δμ/l
- Pressure: α3·Δμ = RT·Δc
- Free activity: α3 = RT·Δc/Δμ = Δc/Δlnc (Gnaiger 1989)
- Three compartments
- Two compartments
- Jd = -b·α·ΔdF = -b·ΔdΠ
- Force: ΔdF = Δμ
- Pressure: α·Δμ = RT·Δc
- Free activity: α = RT·Δc/Δμ = Δc/Δlnc (Gnaiger 1989)
- Two compartments
MitoPedia concepts:
Ergodynamics
