Figure 1

Components of flux variability vs. uptake rate. v _x is the uptake rate of the external metabolite x. Δ _int (black line) is the internal variability, obtained under the constraints: ${\mathit{v}}_{\mathit{\text{gro}}}={\mathit{v}}_{\mathit{\text{gro}}}^{\mathit{\text{max}}}$ and ${\mathit{v}}_{\mathit{\text{ext}}}={\mathit{v}}_{\mathit{\text{ext}}}^{\mathit{\text{max}}}$. Δ _int  + Δ _ext (red line) is the internal and external variability, obtained under the constraint: ${\mathit{v}}_{\mathit{\text{gro}}}={\mathit{v}}_{\mathit{\text{gro}}}^{\mathit{\text{max}}}$. Δ _tot  = Δ _int  + Δ _ext  + Δ _gro (green line) is the total variability, including the internal, external and growth components acting together.