Question 1 Report
A technician uses dialysis tubing to model a stage of dialysis treatment. Fig. 1 shows the tubing filled with blood-like solution and immersed in fresh dialysis solution. The membrane allows small molecules through but not blood cells or proteins.
(a) State the name of the process by which urea moves out of the tubing. [1]
(b) Explain why the dialysis solution must contain no urea at the start of treatment. [2]
(c) Name one large component of blood that should stay inside the tubing. [1]
(a) Urea moves out of the tubing by diffusion. [1 mark]
(b) At the start, dialysis solution must contain no urea so that urea concentration is higher in the blood-like solution than in the dialysis solution. Urea can then diffuse out down its concentration gradient. [2 marks]
(c) One large component that should remain inside is a red blood cell. White blood cells, platelets, or proteins are also acceptable. [1 mark]
Everything you need to excel in your exams