The growth laws of Schaechter,
Maaløe and Kjeldgaard are among the most
striking discoveries in bacterial growth physiology.
They found that cell composition (mass/cell, RNA/cell,
etc.) is a simple function of growth rate alone
irrespective of how that growth rate is established.
I will review the growth laws, and discuss recent
experiments that have uncovered new laws. A phenomenological
model is proposed that suggests the growth laws
arise from the partitioning of the protein synthesizing
machinery of the cell (the ribosomes), and furthermore
indicates a deep connection between growth rate
control and central metabolism. The impact of global
control mechanisms on endogenous and synthetic genetic
circuitry will be considered.