The promoter of the araBAD operon from E. coli is activated in the presence of arabinose and the absence of glucose and directs expression of genes encoding enzymes required for arabinose metabolism. Unlike the cases of lac and gal genes, where a repressor and an activator work together, here two activators work together: AraC and CAP

+ arabinose	AraC binds that sugar and adopts a configuration that allows it to bind DNA as a dimer to the adjacent half-sites, araI1 and araI2
– arabinose	the AraC dimer adopts a different conformation and binds to araO2 and araI1, there is no monomer at site araI2, and so the protein cannot activate the araBAD promoter (araPBAD). This promoter is also controlled by CAP.

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#Question id: 16087

#Unit 7. System Physiology – Animal

The sweat glands are activated by

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#Question id: 7701

#Unit 9. Diversity of Life Forms

The various taxonomic levels (for example, phyla, genera, classes) of the hierarchical classification system differ from each other on the basis of ________

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#Question id: 11911

#Unit 10. Ecological Principles

Michael Moulton and Stuart Pimm (1986) showed how the success of birds introduced to Tahiti or the Hawaiian Islands was dependent on the morphology of the species already present , find out the correct graph represents, morphological differences and the probability of invasion success ;

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#Question id: 7310

#Unit 5. Developmental Biology

Which statement best describes the mechanism for circadian rhythm?

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#Question id: 28079

#Unit 6. System Physiology – Plant

In molecules, two types of excited states can exist singlet and triplet  

(a) The singlet state is relatively long‐lived than triplet and have parallel spin

(b) The singlet state is relatively short‐lived than triplet and have antiparallel spin

(c) The triplet state is relatively long‐lived than singlet and have two parallel spin

(d) The triplet state is relatively long‐lived than singlet and have two anti-parallel spin

Which of the following is correct