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Unformatted text preview: trailer sequences, which are not translated, occur at the beginning and end of the region. E. coli can synthesize 1700 enzymes. Therefore, this small bacterium has the genes for 1700 different mRNAs. Lactose, milk sugar, is split by the enzyme -galactosidase. This enzyme is inducible, since it occurs in large quantities only when lactose, the substrate on which it operates, is present. Conversely, the enzymes for the amino acid tryptophan are produced continuously in growing cells unless tryptophan is present. If tryptophan is present the production of tryptophan-synthesizing enzymes is repressed....
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- Fall '10