During dialysis, the urea concentration in used dialysis fluid gradually approaches that in the blood.
Why does replacing the fluid increase the rate of urea removal?
it decreases the urea concentration difference across the membrane
it increases the urea concentration difference across the membrane
it increases the size of urea molecules passing through the membrane
it decreases the size of urea molecules passing through the membrane
45 exam-style questions on Edexcel GCSE Biology 7.4 Blood glucose and the urinary system, covering 7.4.1 Insulin and blood glucose control, 7.4.2 Glucagon and blood glucose regulation, 7.4.3 Type 1 and type 2 diabetes, 7.4.4 Structure of the urinary system, 7.4.5 Structure and function of the nephron, 7.4.6 ADH and water regulation, 7.4.7 Treatments for kidney failure, and 7.4.8 Production of urea in the liver. Each one has a worked solution and a mark scheme showing where the marks go.