Active drug transport true is ail except -
Ans. is 'c' i.e., Carrier transport is nonsaturable Active transporto As the name suggests active transport is active pumping of drug molecules through a membrane against concentration gradient by a molecular pump (carrier mediated% which requires energy to function.o So, active transport has following characteristics:1. Movement is against concentration gradient2. A molecular pump (carrier protein) is required.3. Energy is requiredo On the basis of energy utilization, active transport is divided to:Primary (Direct) active transportTransporter (carrier protein) binds ATP directly and energy is obtained directly by the hydrolysis of ATP. These transporters (carrier protein) belong to the superfamily of ATP binding cassettee (ABC) transporters whose intracellular loops have ATPase activity.Examples are Na+-K+ ATPase, H+ -K+ ATPase, Ca+2 ATPaseSecondary (Indirect) active transportThe energy to pump one solute is derived from the downhill movement of another solute, i.e. In secondary active transport, molecules are moved through a membrane as a result of the diffusion of other substance.When both molecules move in the same direction it is called svmport (cotransport), e.g. Na+- -glucose transporter in the intestine. Na+-:-iodide transporter in thyroid.When molecules move in opposite directions, it is termed as antiport (exchange transport) e.g. Na+-Ca+2 exchanger in myocardiumAbout option 'c'o Carrier transport (both facilitated diffusion and active transport) are saturable and follows the Michaelis- Menten kinetics.
Energy dependent
Make use of specific transporter protein
Carrier transport is nonsaturable
Carries the drug against the concentration gradient
Pharmacokinetics