Each kidney contains about one million tiny tubules.
The Table shows the concentration of three substances in the blood plasma, in the liquid in the Bowman's capsule and in the urine of a healthy person.
Table
| Substance | Concentration in blood plasma in g\text{g}g per dm3\text{dm}^3dm3 | Concentration in liquid in Bowman's capsule in g\text{g}g per dm3\text{dm}^3dm3 | Concentration in urine in g\text{g}g per dm3\text{dm}^3dm3 |
|---|---|---|---|
| protein | 80 | 0 | 0 |
| glucose | 1.0 | 1.0 | 0 |
| urea | 0.3 | 0.3 | 20 |
Liquid flows through four parts of the kidney tubule.
Write the parts in the order that the liquid flows through them, starting with the Bowman's capsule.
Bowman's capsule collecting duct loop of Henlé proximal convoluted tubule
Explain why there is no protein in the liquid in the Bowman's capsule.
Glucose is in the liquid in the Bowman's capsule but not in the urine.
Explain why.
Calculate how many times greater the concentration of urea is in the urine than in the liquid in the Bowman's capsule.
Suggest why the concentration of urea increases as the liquid passes along the tubule.
72 exam-style questions on OCR GCSE Biology 3.3 Maintaining internal environments, covering 3.3.1 Importance of a constant internal environment, 3.3.2 The skin and body temperature, 3.3.3 Insulin and blood sugar, 3.3.4 Glucagon and blood sugar, 3.3.5 Type 1 and type 2 diabetes, 3.3.6 Osmotic changes in body fluids, 3.3.7 Kidneys and water balance, 3.3.8 Structure of the kidney and tubule, 3.3.9 ADH and kidney tubule permeability, and 3.3.10 Responses to temperature and osmotic challenges. Each one has a worked solution and a mark scheme showing where the marks go.