You are studying regulation of the yeast enzyme glutamine synthetase (GS), which is encoded by the GLN1 gene. You have isolated two mutants, designated gln2– and gln3–, that give decreased GS activity. Mating of either gln2– or gln3– haploids to wild type produces heterozygous diploids that show normal amounts of GS expression. When you cross either a gln2– or gln3– haploid to a gln1– strain the resulting diploids show normal expression of GS.              

 How many units of ß-galactiosidase would you expect to be expressed from deletion 4 in a gln2– mutant?

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#Question id: 34148

#Unit 7. System Physiology – Animal

Assertion (A): Prolactin stimulates the synthesis of casein and lactalbumin during lactation without acting directly on the cell nucleus.

Reason (R): The action of prolactin is dependent on intact microtubules, suggesting involvement of cytoplasmic transport or signaling components.

Choose the correct option:

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#Question id: 34149

#Unit 7. System Physiology – Animal

A scientist finds that infusion of growth hormone into the median eminence of the hypothalamus in experimental animals inhibits the secretion of growth hormone and concludes that this proves that growth hormone feeds back to inhibit GHRH secretion. Do you accept this conclusion?

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#Question id: 34150

#Unit 7. System Physiology – Animal

A 7-year-old boy is evaluated for short stature. His average circulating growth hormone level is within the normal range for his age, but levels of IGF-I are reduced. His growth failure is most likely due to a defect in:

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#Question id: 34151

#Unit 7. System Physiology – Animal

During childbirth, a woman suffers a serious hemorrhage and goes into shock. After she recovers, she displays symptoms of hypopituitarism. Which of the following will not be expected in this patient?

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#Question id: 34152

#Unit 7. System Physiology – Animal

Choose correct one.

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#Question id: 34153

#Unit 7. System Physiology – Animal

Iodide must also exit the thyrocyte across the apical membrane to access the colloid. This transport step is mediated by: