Question

Blood plasma, glomerular filtrate and urine have different concentrations of solutes, such as glucose, protein and urea. explain the processes occurring in the kidney that cause differences in the concentrations of these solutes between blood plasma, glomerular filtrate and urine.

Answer 1

Blood plasma, glomerular filtrate and urine have different concentrations of solutes, such as glucose, protein and urea. Explain the processes occurring in the kidney that cause differences in the concentration of these solutes between blood plasma, glomerular filtrate and urine. (8)

- (filtrate formed by) ultrafiltration;
- glucose / amino acids / soluble components enter Bowman's capsule;
- proteins in blood plasma but not in filtrate / proteins not filtered out (of blood);
- glucose not in urine (normally);
- (selective) reabsorption (of glucose); in the proximal convoluted tubule; by active transport / microvilli increase surface area;
- little/no urea reabsorbed; means concentration increases / urea more concentrated in urine than in blood plasma;
- water reabsorbed from filtrate; by osmosis; in descending limb of nephron / in proximal convoluted tubule;