Which of the following statements about regulation of the trp operon are true? When the Trp concentration in the cell is very low, 1. ribosomes stall at Trp codons in the attenuator. 2. RNA polymerase terminates transcription of the trp operon prematurely. 3. the secondary structure of the RNA transcribed from the leader region changes. 4. enzymes which catalyze the synthesis of Trp are made in greater abundance.

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When the Trp concentration in the cell is very low, ribosomes stall at Trp codons in the attenuator (1), causing the formation of a secondary structure in the RNA transcribed from the leader region (3) that allows the transcription to proceed uninterrupted. This results in enzymes which catalyze the synthesis of Trp are made in greater abundance (4). RNA polymerase does not terminate transcription of the trp operon prematurely (2) in this scenario.

Which of the Following Statements About Regulation of the Trp