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The Ribosome's A, P, and E Sites

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State

An assembled ribosome has three tRNA sites: A accepts an incoming tRNA, P holds the growing peptide, and E releases a used tRNA.

Show

A charged tRNA enters site A, its amino acid is added to the chain at site P, and the emptied tRNA exits site E.

Watch for

These sites are fixed positions in one ribosome, not three ribosomes acting on different tRNAs.