In E. coli, DNA Pol IV (DinB) or DNA Pol V (a complex of the proteins UmuC and UmuD0 ) performs translesion synthesis. 

TLS Online TPP Program

#Id: 5552

#Unit 7. System Physiology – Animal

The principal cells are the primary sites of action of the potassium-sparing diuretics, including spironolactone, eplerenone, amiloride, and triamterene

TLS Online TPP Program

#Id: 5553

#Unit 7. System Physiology – Animal

Intercalated cells play a major role in acid-base regulation and constitute 30 to 40 percent of the cells in the collecting tubules and collecting ducts

TLS Online TPP Program

#Id: 5554

#Unit 7. System Physiology – Animal

There are two types of intercalated cells: type A and type B

TLS Online TPP Program

#Id: 5555

#Unit 7. System Physiology – Animal

Type A intercalated cells  secrete hydrogen ions by a hydrogen-ATPase transporter and by a hydrogen-potassium-ATPase transporter are especially important in eliminating hydrogen ions while reabsorbing bicarbonate in acidosis

TLS Online TPP Program

#Id: 5556

#Unit 7. System Physiology – Animal

Type B intercalated cells have functions opposite to those of type A cells and secrete bicarbonate into the tubular lumen while reabsorbing hydrogen ions in alkalosis

TLS Online TPP Program

#Id: 5557

#Unit 7. System Physiology – Animal

The changes in osmolality and volume in the collecting ducts depend on the amount of vasopressin acting on the ducts.