AP BIOLOGY

Detailed explanation-1: -As the dialysis fluid contains a glucose concentration equal to a normal blood sugar level, this prevents the net movement of glucose across the membrane as no concentration gradient exists. This is very important as the patients’ need to retain glucose for respiration.

Detailed explanation-2: -The formal definition of diffusion in dialysis is movement of solutes as a result of random molecular motions across a semipermeable membrane down its concentration gradient. With dialysis most of the toxin removal is accomplished by diffusion.

Detailed explanation-3: -Dialysis is a separation process in which concentration gradient works as a driving force to separate solute and solvent. Due to the concentration difference, diffusion arises and solute passes across the membrane. Unlike pressure-driven process, this process is slow.

Detailed explanation-4: -The concentrations of solutes (for example potassium, phosphorus, and urea) are undesirably high in the blood, but low or absent in the dialysis solution, and constant replacement of the dialysate ensures that the concentration of undesired solutes is kept low on this side of the membrane.