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: 28929

#Unit 4. Cell Communication and Cell Signaling

In the cytosolic destruction complex, Ci becomes phosphorylated and is proteolytically cleaved by the ubiquitin-proteasome pathway, generating an N-terminal fragment Ci75, which functions as___

TLS Online TPP Program

#Question id: 28930

#Unit 4. Cell Communication and Cell Signaling

Hedgehog (Hh) presence causes__ 

a) binds to Smo, causing Smo to be endocytosed from the cell surface and degraded

b) binds to Ptc, causing Ptc to be endocytosed from the cell surface and degraded

c) degraded Ptc and relieving the inhibition of Smo

d) degraded Smo and relieving the inhibition of Ptc

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#Question id: 28931

#Unit 4. Cell Communication and Cell Signaling

Which of the following activity dissociates Fu-Cos2-Ci complex?

TLS Online TPP Program

#Question id: 28932

#Unit 7. System Physiology – Animal

Which one is correct predict about the connection of hypothalamus with the anterior as well as posterior pituitary ?

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#Question id: 28933

#Unit 7. System Physiology – Animal

Posterior pituitary releasing hormones is__

TLS Online TPP Program

#Question id: 28934

#Unit 7. System Physiology – Animal

Vasopressin and oxytocin each have a neurophysin associated with them in the granules in the neurons;

a) neurophysin I -oxytocin after secretion it function on breast

b) neurophysin II –vasopressin after secretion it function on kidney and blood vessels

c) neurophysin I -oxytocin after secretion it function on kidney and blood vessels

d) neurophysin II –vasopressin after secretion it function on breast