中文（繁體）
中文（简体）
English
S5 Biology: Homeostasis (Paper 2)
S5 Biology: Homeostasis (Paper 2)
The second paper targets thermoregulation: responses to heat and cold, calculating heat lost by evaporation, the balance of production and loss, and the danger of abrupt cooling.
Direct answer Heat means vasodilation and sweating, cold means vasoconstriction and shivering; each gram of evaporated sweat removes 2.4 kJ; when production exceeds loss the surplus raises body temperature.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 25 |
| Difficulty mix | Foundation 4 · Intermediate 3 · Challenge 2 · Error redo 1 |
| Chapter | Chapter: S5 Biology: Homeostasis |
| Level | Four basic, three advanced, two challenge and one error-repair item |
02 Questions (10 items)
- FoundationWhat is normal human body temperature?
- FoundationWhat skin responses help lose heat in hot weather?
- FoundationHow does the body cut heat loss and raise heat production in cold weather?
- FoundationWhy does sweating cool the body?
- IntermediateDuring exercise heat production is 900 kJ/h and heat loss 700 kJ/h. What is the net heat gain?
- IntermediateEach gram of sweat removes about 2.4 kJ on evaporation. How much heat does 300 g remove?
- IntermediateResting heat production is 80 W and shivering can raise it fivefold. What is the shivering rate?
- ChallengeA person sweats 12 g per minute for 30 minutes. What mass of sweat is lost and how much heat is removed?
- ChallengeOne hour of exercise produces 2 000 kJ while 500 g of sweat removes 1 200 kJ. What other routes are needed and how much remains?
- Error redoA student says a fever should be treated by immediate immersion in ice water. Why is that unwise?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | About 37 °C | There is a daily swing of about one degree, but the core stays near 37 °C. |
| 2 | Vasodilation of skin blood vessels, more sweating and relaxed hair erector muscles | Vasodilation brings more blood near the skin surface so heat is lost to the air more readily. |
| 3 | Vasoconstriction reduces heat loss and shivering increases heat production | Vasoconstriction keeps blood in the core, while shivering makes muscles release extra heat. |
| 4 | Evaporating sweat absorbs heat from the skin and carries it away | Evaporation needs latent heat, which is taken from the skin, so the skin cools. |
| 5 | 200 kJ/h, so body temperature rises | Nine hundred minus seven hundred leaves two hundred, and the surplus raises body temperature. |
| 6 | 720 kJ | Three hundred times 2.4 gives 720 kJ, a large part of the work of restoring temperature. |
| 7 | 400 W | Eighty times five gives 400 W, which noticeably slows the fall in temperature for a short time. |
| 8 | 360 g, removing 864 kJ | Twelve times thirty gives 360 g, and multiplying by 2.4 kJ gives 864 kJ. |
| 9 | Radiation, convection and breathing must remove the remaining 800 kJ | Two thousand minus 1 200 leaves 800 kJ, which must come from other routes or the temperature keeps rising. |
| 10 | Ice water constricts skin vessels and blocks heat loss, and may trigger shivering; cooling should be gradual | A sudden cold shock triggers heat-conserving responses, which works against the aim of cooling. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Book an S5 Biology tutorTutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.
