(A) A TF binds to the operator site (O) and activates a gene with a certain probability. (B) For an active gene, RNAP can bind to the promoter, and the probability of activation is determined by the promoter strength [3]. Once this occurs, a transcript is produced and exists until it is degraded by ribonucleases. (C) Transcripts bind to ribosomes (RIB) and translation is initiated to form a protein, which itself degrades or is diluted. (D) An example time trace of the system was modelled by the Gillespie Algorithm [4]. The copy number of active genes fluctuates and the mRNA levels adjust to it depending on the relative timescales of changing gene activity and mRNA lifetime. Similarly, the protein levels adjust to the fluctuation in the mRNA, but with a certain amount of lag due to their slow degradation. (E) Division times are heterogeneous, leading to cell cycle desynchronisation within a colony. Moreover, this introduces heterogeneity into the sizes of newborns. (F) Molecules are partitioned into daughter cells based on a number of factors, such as their concentration, excluded cell volume etc. [5]. Moreover, successive divisions age the pole of the cell, causing it to accumulate damage (age shown above each pole). Poles accumulating age are the method by which we can describe the age of a single cell.