Question

Drug transport across the biological membranes (membrane transport of the drug):

a) during active transport is limited, requires the input of energy (ATP) and can occur also against the electrochemical potential gradient of the drug
b) transport of drugs is mediated by membrane transporters located in intestinal, renal and hepatic epithelia where they function in the absorption and elimination of drugs
c) during facilitated diffusion is limited and can occur also uphill (against) electrochemical potential gradient of the drug
d) during passive diffusion is not limited and can occur also uphill (against) electrochemical potential gradient of the drug

Answer 1

Active transport requires ATP and can move drugs against their concentration gradient, unlike facilitated diffusion and passive diffusion, which move substances along the gradient.

Step-by-step explanation:

The correct answer to the question regarding drug transport across biological membranes is option (a): active transport is limited, requires the input of energy (ATP) and can occur also against the electrochemical potential gradient of the drug. This process involves membrane transporters that utilize ATP to move drugs against their concentration gradients. These transporters are found in vital organs such as the intestines, kidneys, and liver, where they play significant roles in absorption and excretion. On the other hand, facilitated diffusion (option c) and passive diffusion (option d) cannot occur 'uphill' against the concentration gradient without outside energy. These processes rely on the substance moving from an area of higher to lower concentration, without the input of cellular energy.