Intrinsic multiplicative noise drives larger absolute fluctuations in the ON state.

<p><b>A</b> Time evolution of the concentration for . Error bars denote the fluctuations size in each state, which is much higher in the ON state. <b>B</b> Fluctuations in the OFF steady state (filled symbols) and in the ON steady state (empty symbols) for the multiplicative noise model (red) and for the additive noise model (black). Fluctuations are measured as the standard deviation from the steady state. For the multiplicative noise model, fluctuations in the ON state are larger than in the OFF state. For the additive noise model, fluctuations in the OFF and ON states are similar. Standard deviations have been computed over samples of sizes ranging from 100 to 1000 repetitions of the corresponding Langevin dynamics at time t = 100. For the additive noise model we have used a different value for each , as explained in section 3 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031407#s2" target="_blank">Methods</a>.