An X-ray of the cell

The same questions at every level

Function: What does it do? Mechanism: What happens, and in what sequence? Inputs and outputs: What material and energy does it use and produce? Coordination: How do the parts and neighbouring systems work together? Failure: What changes if an activity is lost? Origins: What precursor chemistry, transitions, hurdles and unanswered questions need investigation? Evidence: Which observations, annotations and experiments support the account?

Parts include proteins, RNAs, substrates, cofactors, ions and membranes. The genetic code describes a correspondence implemented by interacting molecules; it is not itself a protein. Present function and prebiotic origins are examined separately.