Repressor

... will not influence the gene). Trans means that it need not be on the same DNA strand(of course it can still be, it just isn't a requirement). The repressor gene acts in trans. It doesn't really matter where it is located, as long as it makes the repressor protein. Cheers. BTW, are you by any chance ...

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cis and trans elements are mostly used in regard with repressor gene cis if the repressor gene is on the same dna strand trans if it is on another one

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... cis-acting elements. I was assuming this was a question about transcription. If the "binding site" is something other than a promoter or repressor binding site, then whatever process this is, must have some sense of directionality to it. Upstream would be something "before" ...

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... lacI −. B. lacZ −. C. lacy −. D. lacZ − lacy −. E. lacI − lacZ −. The answer is A: PG is not an inductor, so it will not be able to inactivate the repressor. Therefore, only a bacterium that lacks a repressor can live in such a medium. E is obviously wrong, as it needs to have the enzyme to break ...

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... which carries out lactose transport to the cell, lacA encodes galactoside-transacetylase. Lac operon is under the control of LacI (repressor), which is inactive in the presence of lactose (inductor). There is a wide diversity of the chemical lactose analogs, for example: Orthonitrophenyl-β-D-galactoside ...

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