Final Answer:
The trp operon consists of B) 2 genes to synthesize tryptophan in E. coli.
Step-by-step explanation:
The trp operon in E. coli is a cluster of genes involved in the synthesis of tryptophan. It consists of B) two main structural genes, trpE and trpA, which encode enzymes essential for different steps in the tryptophan biosynthetic pathway.
These genes work in conjunction to produce tryptophan. The trpE gene codes for the enzyme anthranilate synthase, and the trpA gene codes for the enzyme indole-3-glycerol phosphate synthase.
The operon also includes regulatory elements such as the trp repressor protein and the trp attenuator, which together regulate the expression of the structural genes based on the intracellular concentration of tryptophan. The trp operon's organization and regulatory mechanisms allow E. coli to efficiently synthesize tryptophan when it is scarce in the environment and to downregulate its production when tryptophan is abundant.
Understanding the genetic organization of the trp operon is fundamental in comprehending how bacteria regulate the synthesis of essential amino acids. In this case, the two structural genes, trpE and trpA, play pivotal roles in the enzymatic steps leading to tryptophan synthesis. This genetic arrangement highlights the efficiency and adaptability of bacterial systems in responding to their nutritional environment. In summary, the trp operon consists of two genes, trpE and trpA, orchestrating the biosynthesis of tryptophan in E. coli.