http://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej...
which disputes Lane's claim that bacteria size is limited because ATP production putatively only scales with the area of the cell membrane (necessitating eukaryotes with mitochondria):
> It has previously been pointed out that the plasma membrane serves as the only region for ATP synthesis in bacteria, and since this surface area scales sublinearly with volume it will be outpaced by anything that is proportional to volume (Lane and Martin, 2010). Previous analyses have thus suggested that bacteria are becoming less efficient on a per-protein or per-gene level (Lane and Martin, 2010). However, the surprising superlinear scaling of metabolic rate and the sublinear scaling of both genome size and protein content lead to an increasing efficiency for both components. Figure 4a gives the power per gene as a function of cell size showing that it is increasing superlinearly across bacteria....Thus, it would seem that bacteria are not limited by an energetic efficiency challenge but rather by an energetic surplus that demands ever faster rates of biosynthesis and eventually leads to a space limitation via the packing of ribosomes as discussed earlier.
http://www.nature.com/nature/journal/v531/n7592/full/nature1...