The table below shows the daily water budget (gained and lost) of a healthy domestic dog under normal conditions:
| Water gained | Volume (mL) | Water lost | Volume (mL) |
|---|---|---|---|
| Fluids consumed | 950 | Panting and evaporation | 510 |
| Water in food | 280 | In faeces | 90 |
| Metabolic water | 120 | In urine | □\square□ |
Assuming that the total daily volume of water gained equals the total daily volume of water lost, calculate the volume of urine produced by this dog in mL.
On a hot day, the dog's water loss through panting increases significantly. Explain how the dog's kidneys maintain water balance under these conditions, and describe the resulting effect on the concentration and volume of urine produced.
22 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.