The main applications of normal-phase liquid chromatography are its use to separate

analytes that have low water solubility and those that are not amenable to reversed phase liquid chromatography.

TLS Online TPP Program

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#Unit 2. Cellular Organization

The lac operator is 21-bp sequence with twofold symmetric and is recognized by two subunits of Lac repressor

 

TLS Online TPP Program

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#Unit 2. Cellular Organization

Constitutive mutations occur at 8 positions in the operator between +5 and +17 called OC

TLS Online TPP Program

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#Unit 2. Cellular Organization

Repressor binds with O1and O3 tonhibit expression of lacZ

TLS Online TPP Program

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#Unit 2. Cellular Organization

Effects of mutations in the three lac operators

All three operators are essential for effective repression.

TLS Online TPP Program

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#Unit 2. Cellular Organization

OC are constitutive because repressor protein is unable to bind; this allows RNA polymerase to have unrestrained access to the promoter. 

TLS Online TPP Program

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#Unit 2. Cellular Organization

The Oc mutations are cis-acting/cis dominant, because they affect only the contiguous set of structural genes.