  Replication time is among the most important components of a bacterial cell's
reproductive fitness. Paradoxically, larger cells replicate in less time than
smaller cells despite the fact that building a larger cell requires increased
quantities of raw materials and energy. This feat is primarily accomplished by
the massive over expression of ribosomes, which permits translation of mRNA
into protein, the limiting step in reproduction, to occur at a scale that would
be impossible were it not for the use of parallel processing. In computer
science, spatial parallelism is the distribution of work across the nodes of a
distributed-memory multicomputer system. Despite the fact that a non-negligible
fraction of artificial life research is grounded in formulations based on
spatially parallel substrates, there have been no examples of artificial
organisms that use spatial parallelism to replicate in less time than smaller
organisms. This paper describes artificial cells defined using a
combinator-based artificial chemistry that replicate in less time than smaller
cells. This is achieved by employing extra copies of programs implementing the
limiting steps in the process used by the cells to synthesize their component
parts. Significant speedup is demonstrated, despite the increased complexity of
control and export processes necessitated by the use of a parallel replication
strategy.
