Proteins as RAM

If we could shock-freeze a single cell and then analyze the state of all of its macromolecules, the phosphorylation, GTP-binding etc. state of the proteins would give us an exact description of the cell s environment, its metabolic requirements, any stress it is exposed to etc. In other words, much as we can call DNA the cell s ROM, we can think of the regulatory proteins as its RAM. 

Only the latter function is much less obvious, as, in real life we cannot read the RAM of a cell in the way we sequence its DNA. It is the very nature of a transient, quickly changing working memory which makes this cellular function difficult to study. 

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