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A low level of expression of lac operon ...

A low level of expression of lac operon occurs at all the time. Can you explain the logic behind this phenomena.

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When expression of lac operon is completely lacking, permeases will not be formed. Permeases is necessary for transport of lactose from medium into cells. Due to failure of transport of lactose into cell, it will not act as inducer. Due to this, lac operon cannot be releived from its repressed state.
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