4.1. Units of WC models

Table 4.1 lists the units of each quantity in a WC model.

These units facilitate composition of multiple models of multiple cellular processes. In particular, these units represent dFBA models in volume (l) concentrations rather than in mass (gDCW) concentrations because this makes dFBA compatible with SSA and ODE models that are typically described in volume concentrations.

Table 4.1 Units of WC models.

Quantity	Attributes	Dimensions	Units	Units class
Time	wc_lang.core.Model.time_units	time	s	wc_lang.core.TimeUnit
Compartment density	wc_lang.core.Compartment.density wc_lang.core.Compartment.density_units	mass / volume	g l^-1	wc_lang.core.DensityUnit
Compartment volume	wc_lang.core.Compartment.volume wc_lang.core.Compartment.volume_units	volume	l^-1	wc_lang.core.VolumeUnit
Distribution of initial concentration of a species at the beginning of the cell cycle	wc_lang.core.Concentration.distribution wc_lang.core.Concentration.mean wc_lang.core.Concentration.std wc_lang.core.Concentration.units	molecule, molecule volume-1	molecule, M	wc_lang.core.ConcentrationUnit
Species count	wc_lang.core.Species.units	molecule	molecule	wc_lang.core.MoleculeCountUnit
Observable count	wc_lang.core.ObservableExpression.expression wc_lang.core.Observable.units	molecule	molecule	wc_lang.core.MoleculeCountUnit
Observable coefficient	wc_lang.core.ObservableExpression.expression	dimensionless	none	wc_lang.core.ObservableCoefficientUnit
Reaction participant	wc_lang.core.SpeciesCoefficient.coefficient	dimensionless	none	wc_lang.core.ReactionParticipantUnit
Reaction rate	wc_lang.core.RateLawExpression.expression wc_lang.core.RateLaw.units wc_lang.core.DfbaObjective.reaction_rate_units wc_lang.core.DfbaObjReaction.units	time-1	s-1,	wc_lang.core.ReactionRateUnit
Reaction flux bounds	wc_lang.core.Reaction.flux_min wc_lang.core.Reaction.flux_max wc_lang.core.Reaction.flux_bound_units	volume-1 time-1	M s^-1	wc_lang.core.ReactionFluxUnit
dFBA objective	wc_lang.core.DfbaObjectiveExpresssion.expression wc_lang.core.DfbaObjective.units	time-1	s^-1	wc_lang.core.DfbaObjectiveUnit
dFBA objective coefficient	wc_lang.core.DfbaObjectiveExpresssion.expression wc_lang.core.DfbaObjective.coefficient_units	time	s	wc_lang.core.DfbaObjectiveCoefficientUnit
dFBA objective species	wc_lang.core.DfbaObjSpecies.value wc_lang.core.DfbaObjSpecies.units	volume^-1 time^-1, gDCW^-1 time^-1	M s^-1 mol gDCW^-1 s^-1	wc_lang.core.DfbaObjSpeciesUnit
Function	wc_lang.core.FunctionExpression.expression wc_lang.core.Function.units	various	various
Parameter	wc_lang.core.Parameter.value wc_lang.core.Parameter.units	various	various
Stop condition	wc_lang.core.StopCondition.expression wc_lang.core.StopCondition.units	dimensionless	none	wc_lang.core.StopConditionUnit