📚 Effects of Smoking: KS3 CIE Exam Question & Mark Scheme | 吸烟的影响：KS3 CIE 考试题与评分标准
Smoking is one of the most important lifestyle factors covered in the KS3 CIE Biology syllabus. This article explains the key effects of smoking on the human body, provides a realistic exam question, and breaks down a full mark scheme so you can see exactly how marks are awarded.
吸烟是 KS3 CIE 生物学大纲中最重要的生活方式因素之一。本文将解释吸烟对人体的主要影响，提供一道真实考试题，并详细拆解评分标准，让你清楚了解分数是如何给出的。
Along the way you will revisit the gas exchange system, the circulatory system and cell biology, because the smoking topic is really a test of whether you can link these three ideas together in one extended answer. Read the science sections first, then attempt the exam question before you look at the mark scheme.
在阅读过程中，你会复习到气体交换系统、循环系统和细胞生物学，因为吸烟这一话题实际上是在考查你能否把这三个知识点串联在一个长答案中。建议先读完科学原理部分，再动手做考试题，最后才看评分标准。
1. Why Smoking Matters in KS3 CIE Biology | 为什么吸烟在 KS3 CIE 生物中重要？
Smoking is a classic topic because it links the gas exchange system, the circulatory system and cell biology in one real-world example. Exam questions often ask you to identify harmful substances in tobacco smoke and explain how they damage the body.
吸烟是一个经典话题，因为它将气体交换系统、循环系统和细胞生物学结合在一个实际例子中。考试题经常要求你识别烟草烟雾中的有害物质，并解释它们如何损害身体。
In CIE mark schemes, examiners look for specific scientific keywords such as 'tar', 'carbon monoxide', 'nicotine', 'cilia', 'mucus', 'haemoglobin' and 'carcinogen'. Using these terms accurately in a sentence is often enough to pick up marks.
在 CIE 评分标准中，考官寻找特定的科学关键词，如焦油（tar）、一氧化碳（carbon monoxide）、尼古丁（nicotine）、纤毛（cilia）、黏液（mucus）、血红蛋白（haemoglobin）和致癌物（carcinogen）。在句子中准确使用这些术语通常就足以得分。
s follows the pattern: substance → target organ or cell → effect → consequence for health.
这个话题频繁出现的另一个原因是，它奖励清晰的因果关系表述。优秀的答案总是遵循这样的模式：物质 → 目标器官或细胞 → 影响 → 对健康的后果。
| Key word 关键词 | Meaning 含义 |
| Tar 焦油 | Sticky mixture that settles in the lungs; contains carcinogens 沉积在肺部的黏性混合物，含致癌物 |
| Nicotine 尼古丁 | Addictive drug that stimulates the nervous system 作用于神经系统的成瘾性药物 |
| Carbon monoxide 一氧化碳 | Toxic gas that binds to haemoglobin 与血红蛋白结合的有毒气体 |
| Cilia 纤毛 | Tiny hair-like structures that sweep mucus upwards 把黏液向上扫动的微小毛状结构 |
| Carcinogen 致癌物 | A substance that can cause cancer 能引起癌症的物质 |
2. Harmful Chemicals in Tobacco Smoke | 烟草烟雾中的有害化学物质
Tobacco smoke contains thousands of chemicals, but for KS3 CIE you need to focus on three: nicotine, tar and carbon monoxide. Each one has a distinct target in the body and causes a distinct type of harm.
烟草烟雾含有数千种化学物质，但对于 KS3 CIE，你只需要关注三种：尼古丁、焦油和一氧化碳。每一种在体内都有不同的目标，并造成不同类型的伤害。
Nicotine is the addictive substance that acts on the nervous system. It stimulates the release of adrenaline, which increases heart rate and narrows blood vessels. Carbon monoxide is a toxic gas that binds to haemoglobin. Tar is a thick, sticky mixture that collects in the lungs and contains cancer-causing chemicals.
尼古丁是成瘾物质，作用于神经系统。它刺激肾上腺素释放，从而加快心率并使血管变窄。一氧化碳是一种有毒气体，会与血红蛋白结合。焦油是一种黏稠的混合物，会积聚在肺部，并含有致癌化学物质。
A useful revision habit is to sort every fact you learn under one of these three headings. If a fact cannot be filed under nicotine, tar or carbon monoxide, it is probably about the consequences of smoking rather than the chemicals themselves.
一个有用的复习习惯是：把你学到的每一个事实归入这三个标题之一。如果一个事实无法归入尼古丁、焦油或一氧化碳，那它很可能讲的是吸烟的后果，而不是化学物质本身。
3. Quick Recap: How the Gas Exchange System Works | 快速回顾：气体交换系统如何工作
Before you can explain the damage, you must be able to describe the normal structure. Air travels down the trachea, then through the bronchi and bronchioles, and finally reaches the alveoli in the lungs.
在解释损害之前，你必须能够描述正常结构。空气经气管下行，通过支气管和细支气管，最终到达肺部的肺泡。
Alveoli are ideally adapted for diffusion: there are millions of them, giving a very large surface area; their walls are only one cell thick, so the diffusion distance is short; they have a rich blood supply, which maintains a steep concentration gradient; and their surface is moist, so gases can dissolve.
肺泡非常适合扩散：数量以百万计，提供非常大的表面积；壁只有一层细胞厚，扩散距离很短；血液供应丰富，维持陡峭的浓度梯度；表面湿润，使气体可以溶解。
Oxygen diffuses from the air in the alveoli into the blood, where it combines with haemoglobin inside red blood cells. Carbon dioxide diffuses in the opposite direction, from the blood into the alveoli, and is breathed out.
氧气从肺泡中的空气扩散进入血液，在红细胞内与血红蛋白结合。二氧化碳则向相反方向扩散，从血液进入肺泡，然后被呼出。
Haemoglobin + Oxygen ⇌ Oxyhaemoglobin
The airways are lined with cells that produce mucus, which traps dust and bacteria, and with cilia, which beat in waves to sweep the mucus up towards the throat so it can be swallowed.
呼吸道内壁有分泌黏液的细胞，黏液可以捕获灰尘和细菌；还有纤毛，纤毛以波浪状摆动，把黏液向上扫向喉部，以便被吞咽下去。
4. Effects on the Lungs: Tar, Mucus and Cilia | 对肺的影响：焦油、黏液与纤毛
Tar is the substance responsible for most of the direct damage to the airways. It is sticky, so it settles on the lining of the trachea, bronchi and bronchioles, and it contains carcinogens that can trigger uncontrolled cell division and lead to lung cancer.
焦油是造成气道直接损害的主要物质。它很黏，会附着在气管、支气管和细支气管的内壁上，并且含有致癌物，可能引发细胞不受控制地分裂，导致肺癌。
Tar also paralyses the cilia and eventually destroys them. Without working cilia, mucus cannot be swept away from the lungs, so it accumulates and blocks the airways.
焦油还会使纤毛麻痹，最终将其破坏。没有正常工作的纤毛，黏液就无法从肺部被清除，于是积聚起来，堵塞气道。
The trapped mucus carries dust and bacteria deep into the lungs, which increases the risk of chest infections such as bronchitis. The body tries to clear the mucus by coughing, which is why many smokers develop a persistent 'smoker's cough'.
被滞留的黏液把灰尘和细菌带入肺部深处，增加了支气管炎等胸部感染的风险。身体试图通过咳嗽清除黏液，这就是为什么许多吸烟者会长期出现"吸烟者咳嗽"。
In the long term, tar and the other chemicals in smoke destroy the walls of the alveoli. The alveoli collapse and merge into larger, fewer air sacs, so the surface area for gas exchange falls sharply. This condition is called emphysema, and it makes breathing, especially during exercise, very difficult.
长期来看，焦油和烟雾中的其他化学物质会破坏肺泡壁。肺泡塌陷并融合成更大、更少的囊泡，气体交换的表面积急剧下降。这种疾病称为肺气肿，会使呼吸（尤其是在运动时）变得非常困难。
- Tar → paralyses and destroys cilia → mucus builds up → infections and coughing. 焦油 → 使纤毛麻痹并破坏纤毛 → 黏液积聚 → 感染与咳嗽。
- Tar → contains carcinogens → mutations in lung cells → lung cancer. 焦油 → 含致癌物 → 肺细胞突变 → 肺癌。
- Tar and other chemicals → alveoli walls destroyed → reduced surface area → emphysema. 焦油及其他化学物质 → 肺泡壁被破坏 → 表面积减少 → 肺气肿。
5. Carbon Monoxide and the Circulatory System | 一氧化碳与循环系统
Carbon monoxide is a colourless, odourless and toxic gas. It enters the blood through the alveoli and binds to haemoglobin in red blood cells, forming carboxyhaemoglobin.
一氧化碳是一种无色、无味的有毒气体。它通过肺泡进入血液，与红细胞中的血红蛋白结合，形成碳氧血红蛋白。
Haemoglobin + Carbon monoxide → Carboxyhaemoglobin
Carbon monoxide binds to haemoglobin much more readily than oxygen does, and it is not easily released. This means fewer haemoglobin molecules are available to carry oxygen, so the blood carries less oxygen around the body.
一氧化碳比氧气更容易与血红蛋白结合，而且不易被释放。这意味着可用于运输氧气的血红蛋白分子减少，因此血液向全身输送的氧气也随之减少。
As a result, cells receive less oxygen for aerobic respiration, so less energy is released. Muscles tire more quickly, and the heart and brain, which have high oxygen demands, are especially affected.
结果，细胞获得的有氧呼吸所需氧气减少，释放的能量也随之减少。肌肉更快疲劳，而需氧量高的心脏和大脑尤其受到影响。
Carbon monoxide and other chemicals in smoke also damage the smooth lining of the arteries. Fatty deposits then build up on the damaged areas, narrowing the arteries and raising blood pressure. If a blood clot forms on a deposit, it can block the artery completely, causing a heart attack or a stroke.
一氧化碳和烟雾中的其他化学物质还会损伤动脉光滑的内壁。随后脂肪沉积物在受损部位堆积，使动脉变窄并升高血压。如果血块在沉积物上形成，可能完全阻塞动脉，导致心脏病发作或中风。
6. Nicotine: Addiction, Heart Rate and Blood Pressure | 尼古丁：成瘾、心率与血压
Nicotine is the drug in tobacco that causes addiction. It reaches the brain within seconds of inhaling and triggers the release of adrenaline, a hormone that prepares the body for action.
尼古丁是烟草中导致成瘾的物质。吸入后几秒内就能到达大脑，并刺激肾上腺素的释放，这是一种让身体进入应激状态的激素。
Adrenaline increases the heart rate and makes the heart beat more forcefully. It also causes blood vessels to narrow, which raises blood pressure. A smoker's heart therefore works harder than a non-smoker's, both during rest and during exercise.
肾上腺素会加快心率，使心脏搏动更有力。它还会使血管变窄，从而升高血压。因此，无论休息还是运动时，吸烟者的心脏都比不吸烟者更辛苦。
Because nicotine is addictive, smokers find it very difficult to stop. The addiction is one reason the health effects continue for many years, since each cigarette repeats the damage to the airways and arteries.
由于尼古丁具有成瘾性，吸烟者很难戒掉。成瘾是这些健康影响持续多年的原因之一，因为每吸一支烟都会重复对气道和动脉造成损害。
Nicotine itself does not cause cancer, but it keeps people smoking, and it is the other chemicals in tar that cause the cancers. This distinction is a common exam question, so keep it clear in your notes.
尼古丁本身不会致癌，但它让人持续吸烟，而真正致癌的是焦油中的其他化学物质。这个区别是常见的考点，请在笔记中写清楚。
7. Long-Term Health Consequences | 长期健康后果
The long-term effects of smoking are the result of years of repeated damage. The lungs, the heart and the blood vessels all suffer, and many of the changes are permanent.
吸烟的长期影响是多年反复损害的结果。肺、心脏和血管都会受损，而且许多变化是永久性的。
In the lungs, the main risks are lung cancer, chronic bronchitis and emphysema. Together, bronchitis and emphysema are often described as chronic obstructive pulmonary disease, which gradually reduces breathing capacity.
在肺部，主要风险是肺癌、慢性支气管炎和肺气肿。支气管炎和肺气肿常被合称为慢性阻塞性肺疾病，它会逐渐降低呼吸能力。
In the circulatory system, smoking increases the risk of coronary heart disease, heart attack, stroke and high blood pressure. Smokers also take longer to recover from illness and from surgery, because their blood carries less oxygen.
在循环系统中，吸烟会增加冠心病、心脏病发作、中风和高血压的风险。吸烟者从疾病和手术中恢复的时间也更长，因为他们的血液携带的氧气更少。
| Substance 物质 | Target 作用目标 | Effect 影响 | Long-term risk 长期风险 |
| Nicotine 尼古丁 | Nervous system 神经系统 | Addiction; faster heart rate; narrower blood vessels 成瘾；心率加快；血管变窄 | High blood pressure 高血压 |
| Tar 焦油 | Airways and alveoli 气道与肺泡 | Destroys cilia; blocks airways; carcinogenic 破坏纤毛；堵塞气道；致癌 | Lung cancer; bronchitis; emphysema 肺癌；支气管炎；肺气肿 |
| Carbon monoxide 一氧化碳 | Haemoglobin 血红蛋白 | Less oxygen transported 运输的氧气减少 | Heart attack; stroke 心脏病发作；中风 |
8. Smoking, Pregnancy and Passive Smoking | 吸烟、怀孕与被动吸烟
If a pregnant woman smokes, the carbon monoxide in her blood reduces the oxygen supply to the fetus. Nicotine also narrows the blood vessels in the placenta, so fewer nutrients reach the developing baby.
如果孕妇吸烟，她血液中的一氧化碳会减少对胎儿的氧气供应。尼古丁还会使胎盘中的血管变窄，使到达发育中胎儿的营养物质减少。
This can lead to a baby with a low birth weight, an increased risk of premature birth, and a higher risk of health problems in the first months of life. This is a good example of how a lifestyle choice in one person affects another.
这可能导致婴儿出生体重偏低、早产风险增加，以及出生后最初几个月健康问题风险升高。这是一个很好的例子，说明一个人的生活方式选择会影响到另一个人。
Passive smoking means breathing in other people's tobacco smoke. Non-smokers who live or work with smokers breathe in the same harmful chemicals, so they face a higher risk of lung cancer, heart disease, asthma and chest infections.
被动吸烟是指吸入他人的烟草烟雾。与吸烟者一起生活或工作的不吸烟者会吸入同样的有害化学物质，因此他们患肺癌、心脏病、哮喘和胸部感染的风险更高。
Children are especially vulnerable, because their lungs are still developing and they breathe faster than adults. Smoke in the home increases the chance of asthma attacks, ear infections and chest infections.
儿童尤其容易受到伤害，因为他们的肺仍在发育，而且呼吸频率比成人快。家庭中的烟雾会增加哮喘发作、耳部感染和胸部感染的机会。
9. Practice Exam Question (CIE Style) | 练习题（CIE 风格）
Now try the question on your own before reading the mark scheme. Write your answers in full sentences and use scientific keywords wherever you can.
请先自己尝试作答，再阅读评分标准。请用完整句子作答，并尽量使用科学关键词。
Question 1
(a) Name two harmful substances found in tobacco smoke. (2 marks)
(a) 写出烟草烟雾中两种有害物质的名称。（2 分）
(b) Explain how carbon monoxide in tobacco smoke reduces the amount of oxygen carried by the blood. (3 marks)
(b) 解释烟草烟雾中的一氧化碳如何减少血液运输的氧气量。（3 分）
(c) Explain how smoking damages the cilia in the airways and why this is harmful to the smoker. (3 marks)
(c) 解释吸烟如何损害气道中的纤毛，以及为什么这对吸烟者有害。（3 分）
Read the command words carefully. 'Name' only requires the substance; 'Explain' requires a reason, usually with the word 'because', and rewards a clear chain of cause and effect.
请仔细阅读指令词。"Name"只需要写出物质名称；"Explain"需要给出理由，通常要用"because"连接，并奖励清晰的因果链。
10. Mark Scheme and Examiner Notes | 评分标准与考官提示
The mark scheme below shows the acceptable marking points. In CIE papers, any correct alternative wording that shows the same scientific idea is usually accepted.
下面的评分标准展示了可接受的得分点。在 CIE 试卷中，任何表达相同科学思想的正确替代表述通常都被接受。
| Part 部分 | Marking points 得分点 | Marks 分值 |
| (a) | Any two of: nicotine / tar / carbon monoxide 任意两项：尼古丁 / 焦油 / 一氧化碳 | 2 |
| (b) | Carbon monoxide binds to haemoglobin (1); forms carboxyhaemoglobin (1); so less haemoglobin is available to carry oxygen / less oxygen transported to cells (1) 一氧化碳与血红蛋白结合（1）；形成碳氧血红蛋白（1）；因此可用于运输氧气的血红蛋白减少／输送到细胞的氧气减少（1） | 3 |
| (c) | Tar paralyses and destroys the cilia (1); mucus cannot be swept away and builds up in the airways (1); bacteria and dust trapped in the mucus cause chest infections / the smoker coughs to clear it (1) 焦油使纤毛麻痹并将其破坏（1）；黏液无法被清除而积聚在气道（1）；被黏液捕获的细菌和灰尘引起胸部感染／吸烟者咳嗽以清除它（1） | 3 |
Examiner notes. In part (a), do not waste time writing long explanations, because the question only asks for names. In part (b), many students write 'carbon monoxide is poisonous' and stop; this gains no marks because it does not explain the effect on oxygen transport. In part (c), you must mention both the damage to the cilia and the consequence of that damage.
考官提示。在 (a) 部分，不要浪费时间写长篇解释，因为题目只要求写出名称。在 (b) 部分，许多学生只写"一氧化碳有毒"就结束，这不得分，因为它没有解释对氧气运输的影响。在 (c) 部分，你必须同时提到对纤毛的损害以及该损害造成的后果。
Remember that marks in CIE papers are given for the correct scientific idea, not for beautiful English. Keep your sentences short, and use one marking point per sentence so the examiner can find each idea easily.
请记住，CIE 试卷的分数是给正确的科学思想的，而不是给漂亮的英语。句子要短，一句话对应一个得分点，方便考官找到每个要点。
11. Model Answer at Full Marks | 满分范文
A model answer for parts (b) and (c) is shown below. Notice how every sentence contains one clear marking point.
下面是 (b) 和 (c) 部分的满分范文。注意每一句话都包含一个清晰的得分点。
(b) Carbon monoxide in tobacco smoke combines with the haemoglobin in red blood cells, forming carboxyhaemoglobin. Carbon monoxide binds more strongly than oxygen, so the haemoglobin cannot pick up as much oxygen. Therefore the blood carries less oxygen to the body's cells, so less aerobic respiration occurs and less energy is released.
(b) 烟草烟雾中的一氧化碳与红细胞中的血红蛋白结合，形成碳氧血红蛋白。一氧化碳的结合力比氧气更强，因此血红蛋白无法携带同样多的氧气。结果是血液输送到身体细胞的氧气减少，有氧呼吸减少，释放的能量也随之减少。
(c) Tar in tobacco smoke paralyses and eventually destroys the cilia that line the trachea and bronchi. The cilia normally sweep mucus, dust and bacteria up towards the throat. Without working cilia, the mucus accumulates in the airways and blocks them, and the bacteria trapped in it can cause chest infections such as bronchitis, which is why smokers often have a persistent cough.
(c) 烟草烟雾中的焦油使气管和支气管内壁的纤毛麻痹，最终将其破坏。纤毛本来负责把黏液、灰尘和细菌向上扫向喉部。没有正常工作的纤毛，黏液会积聚在气道中并造成堵塞，其中捕获的细菌可能引起支气管炎等胸部感染，这就是吸烟者常常持续咳嗽的原因。
If you can write answers like these without looking at your notes, you are ready for the smoking question in a KS3 CIE examination.
如果你能不看书就写出这样的答案，说明你已经准备好应对 KS3 CIE 考试中的吸烟类题目了。
12. Revision Checklist and Common Mistakes | 复习清单与常见错误
Use the checklist below to test yourself. Tick each item only when you can explain it out loud without help.
用下面的清单自我检测。只有在不看资料的情况下能口头解释清楚，才在该项前打勾。
- I can name the three main harmful substances in tobacco smoke. 我能写出烟草烟雾中三种主要有害物质。
- I can describe how tar destroys cilia and why mucus then builds up. 我能描述焦油如何破坏纤毛以及黏液为何会积聚。
- I can explain how carbon monoxide reduces oxygen transport by forming carboxyhaemoglobin. 我能解释一氧化碳如何通过形成碳氧血红蛋白减少氧气运输。
- I can explain how nicotine causes addiction, a faster heart rate and narrowed blood vessels. 我能解释尼古丁如何导致成瘾、心率加快和血管变窄。
- I can link smoking to lung cancer, bronchitis, emphysema, heart attack and stroke. 我能把吸烟与肺癌、支气管炎、肺气肿、心脏病发作和中风联系起来。
- I can describe one effect of smoking during pregnancy and one effect of passive smoking. 我能描述孕期吸烟的一种影响和被动吸烟的一种影响。
Common mistakes to avoid: saying that nicotine causes cancer, saying that tar reduces the oxygen carried by the blood, and forgetting to state the consequence after describing the damage.
要避免的常见错误：说尼古丁致癌、说焦油减少血液携带的氧气量，以及只描述损害
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