A scientist measures the concentrations of two substances in filtered fluid from a kidney tubule and in the urine from the same person.
The results are shown in the table.
| Substance | Concentration in filtered fluid in mmol per dm³ | Concentration in urine in mmol per dm³ |
|---|---|---|
| Glucose | 5.0 | 0.0 |
| Urea | 6.0 | 320.0 |
Compare the concentrations of glucose and urea in the filtered fluid and the urine. Explain how the results show that selective reabsorption has occurred.
85 exam-style questions on AQA GCSE Biology 5.3 Hormonal coordination in humans, covering 5.3.1 Human endocrine system, 5.3.2 Control of blood glucose concentration, 5.3.3 Maintaining water and nitrogen balance in the body, 5.3.4 Hormones in human reproduction, 5.3.5 Contraception, 5.3.6 The use of hormones to treat infertility (HT only), and 5.3.7 Negative feedback (HT only). Each one has a worked solution and a mark scheme showing where the marks go.