Activators can recruit factors needed for polymerase to initiate or elongate transcription. In all of these functions, the activator is merely recruiting proteins to the promoter. In bacteria, RNA polymerase is the only protein that needs to be recruited; this is not the case in eukaryotes. Indeed, in eukaryotes, a given activator might work in all three ways:

1.    Recruitment of nucleosome modifiers and remodelers	i.     “open” the promoter
2.    Recruitment of general transcription factors and mediators	ii.      That stimulate Pol II initiation and elongation
3.       Recruitment of protein complexes	iii.     To recruit PTEFb/SEC

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#Question id: 12072

#Unit 7. System Physiology – Animal

If the average hydrostatic pressure in the glomerular capillaries is 50 mm Hg, the hydrostatic pressure in the Bowman’s space is 12 mm Hg, the average colloid osmotic pressure in the glomerular capillaries is 30 mm Hg, and there is no protein in the glomerular ultrafiltrate, what is the net pressure driving glomerular filtration?

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#Question id: 12073

#Unit 7. System Physiology – Animal

The figure above shows the concentration of inulin at different points along the renal tubule, expressed as the tubular fluid/plasma ratio of inulin concentration. If inulin is not reabsorbed, what is the approximate percentage of the filtered water that has been reabsorbed prior to the distal convoluted tubule?

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#Question id: 12074

#Unit 7. System Physiology – Animal

Which of the following tends to increase potassium secretion by the cortical collecting tubule?

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#Question id: 12075

#Unit 7. System Physiology – Animal

A 48-year-old woman complains of severe polyuria (producing about 0.5 L of urine each hour) and polydipsia (drinking two to three glasses of water every hour). Her urine contains no glucose, and she is placed on overnight water restriction for further evaluation. The next morning, she is weak and confused, her sodium concentration is 160 mEq/L, and her urine osmolarity is 80 mOsm/L. Which of the following is the most likely diagnosis?

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#Question id: 12076

#Unit 7. System Physiology – Animal

Furosemide (Lasix) is a diuretic that also produces natriuresis. Which of the following is an undesirable side effect of furosemide due to its site of action on the renal tubule?

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#Question id: 12077

#Unit 7. System Physiology – Animal

 RU486 causes abortion if it is administered before or soon after implantation. What is the specific effect of RU486?