Begin is the common term: to begin knitting a sweater. Commence is a more formal word, often suggesting a more prolonged or elaborate beginning: to commence proceedings in court. Initiate implies an active and often ingenious first act in a new field: to initiate a new procedure.
Structure of the trp operon. The trp operon is an operon â a group of genes that are used, or transcribed, together â that codes for the components for production of tryptophan. The trp operon is present in many bacteria, but was first characterized in Escherichia coli.The operon is regulated so that when tryptophan is present in the environment, the genes for tryptophan synthesis are not expressed.It was an important experimental system for learning about gene regulation, and is commonly used to teach gene regulation.he trp operon is present in many bacteria, but was first characterized in Escherichia coli. The operon is regulated so that when tryptophan is present in the environment, the genes for tryptophan synthesis are not expressed.
The regulation of translation by heme regulated inhibitor (HRI). Control of translation by heme is important in erythrocytes since these cells are enucleate and contain primarily globin mRNA. When the level of heme (required for the synthesis of biologically active hemoglobin) is low it would be inefficient for erythrocytes to synthesize globin protein.