📚 Core Knowledge of Year 7 CIE Biology | 核心知识点梳理
Welcome to your Year 7 CIE Biology revision guide! This article covers the essential topics you will encounter: the seven life processes, cell structure, levels of organisation, classification, human nutrition and digestion, the respiratory and circulatory systems, photosynthesis, reproduction basics, and ecosystems. Having a solid grasp of these areas will help you build a strong foundation for future science learning and examination success.
欢迎来到七年级 CIE 生物复习指南！本文将梳理你将遇到的核心内容：七大生命过程、细胞结构、生命体的结构层次、生物分类、人体营养与消化、呼吸系统和循环系统、光合作用、生殖基础以及生态系统。扎实掌握这些领域将为未来的科学学习和考试成功打下坚实基础。
1. Characteristics of Living Things | 生物的特征
All living organisms share seven life processes, often remembered by the mnemonic 'MRS GREN' — Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion and Nutrition.
所有生物都共有七大生命过程，常用助记符 'MRS GREN' 来记忆——运动(Movement)、呼吸(Respiration)、感应(Sensitivity)、生长(Growth)、生殖(Reproduction)、排泄(Excretion)和营养(Nutrition)。
Movement is the ability to change position or move parts of the body. Respiration is the chemical process that releases energy from food. Sensitivity is the ability to detect and respond to changes in the environment. Growth is a permanent increase in size and cell number. Reproduction produces new offspring to ensure species survival. Excretion removes metabolic waste products. Nutrition involves taking in and using food for energy and building materials.
运动指改变身体位置或移动身体部位的能力。呼吸指从食物中释放能量的化学过程。感应指探测和回应环境变化的能力。生长是体积和细胞数量的永久性增加。生殖产生新后代以保证物种延续。排泄清除代谢废物。营养指摄取并利用食物获取能量和构建物质。
2. Cell Structure and Function | 细胞结构与功能
Cells are the basic building blocks of all living organisms. Animal cells have a cell membrane, cytoplasm, nucleus and mitochondria. Plant cells contain the same parts plus a cell wall, a large permanent vacuole and often chloroplasts.
细胞是所有生物的基本构建单位。动物细胞有细胞膜、细胞质、细胞核和线粒体。植物细胞除了这些结构之外，还有细胞壁、一个中央大液泡，通常还含有叶绿体。
| Cell part | Function (English) | 功能 (中文) |
| Cell membrane | Controls which substances enter and leave the cell | 控制物质进出细胞 |
| Cytoplasm | Jelly-like substance where chemical reactions occur | 胶状物质，是化学反应发生的场所 |
| Nucleus | Contains DNA and controls cell activities | 含有DNA，控制细胞活动 |
| Mitochondria | Site of aerobic respiration, releasing energy | 有氧呼吸的场所，释放能量 |
| Cell wall | Rigid outer layer that provides support (plants only) | 坚硬外层，提供支持（仅植物） |
| Vacuole | Filled with cell sap, helps maintain shape (plants) | 含有细胞液，帮助维持形状（植物） |
| Chloroplasts | Contain chlorophyll, absorb light for photosynthesis | 含有叶绿素，吸收光能进行光合作用 |
Some organisms are unicellular (made of one cell, e.g. bacteria), whereas others are multicellular (made of many cells, e.g. humans).
有些生物是单细胞的（由一个细胞构成，如细菌），而另一些是多细胞的（由许多细胞构成，如人类）。
3. Levels of Organisation | 生命体的结构层次
In multicellular organisms, cells are organised into increasingly complex levels: cells, tissues, organs, organ systems and finally the whole organism.
在多细胞生物中，细胞按照越来越复杂的层次组织起来：细胞、组织、器官、器官系统，最后到完整的生物体。
A tissue is a group of similar cells working together, such as muscle tissue. An organ is made of different tissues performing a specific function, like the stomach. Organ systems are groups of organs that work together, e.g. the digestive system. Together, all systems form the organism.
组织是一群形态功能相似的细胞共同工作，比如肌肉组织。器官由不同的组织构成，执行特定功能，例如胃。器官系统是一组协同工作的器官，例如消化系统。所有系统组合在一起就构成了生物体。
4. Classification of Living Organisms | 生物分类
Biologists classify organisms into groups to make them easier to study. The largest groups are the five kingdoms: Animals, Plants, Fungi, Protists and Prokaryotes. Within the animal kingdom, vertebrates are further divided into five classes.
生物学家对生物进行分类以便研究。最大的类群是五个界：动物界、植物界、真菌界、原生生物界和原核生物界。在动物界中，脊椎动物又分为五个纲。
- Mammals — have hair or fur, give birth to live young and feed milk. / 哺乳动物——有毛发，胎生并哺乳。
- Birds — have feathers, lay hard-shelled eggs and possess a beak. / 鸟类——有羽毛，产硬壳卵，有喙。
- Reptiles — dry scaly skin, lay soft-shelled eggs on land. / 爬行动物——干燥的鳞片皮肤，在陆地产软壳卵。
- Amphibians — moist skin, live both in water and on land, lay jelly-covered eggs in water. / 两栖动物——湿润皮肤，水陆两栖，在水中产胶质包裹的卵。
- Fish — live in water, have gills and scales, and lay eggs. / 鱼类——生活在水里，有鳃和鳞，产卵。
Invertebrates such as arthropods (insects, spiders, crustaceans) are also important. Carl Linnaeus introduced the binomial naming system, where each species is given a two-part Latin name, e.g. Homo sapiens for humans.
无脊椎动物如节肢动物（昆虫、蜘蛛、甲壳类）也很重要。卡尔·林奈引入了双名命名法，每个物种都有一个由两部分拉丁文组成的名字，比如人类是 Homo sapiens。
5. Human Nutrition and Digestion | 人体营养与消化
A balanced diet must include seven nutrient groups: carbohydrates (for energy), proteins (for growth and repair), lipids (fats, for energy storage and insulation), vitamins, minerals, water and dietary fibre (roughage to aid bowel movement).
均衡膳食必须包含七类营养物质：碳水化合物（供能）、蛋白质（用于生长和修复）、脂类（脂肪，储存能量和保温）、维生素、矿物质、水和膳食纤维（粗纤维，帮助肠道蠕动）。
Digestion breaks down large insoluble food molecules into small soluble ones that can be absorbed into the blood. The main organs of the digestive system are:
消化作用将大而不可溶的食物分子分解成小而可溶的分子，以便被血液吸收。消化系统的主要器官有：
- Mouth — chews food, salivary amylase starts starch digestion. / 口腔——咀嚼食物，唾液淀粉酶开始消化淀粉。
- Oesophagus — pushes food down to the stomach by peristalsis. / 食道——通过蠕动将食物推入胃。
- Stomach — churns food and produces protease enzymes and hydrochloric acid. / 胃——搅拌食物，产生蛋白酶和盐酸。
- Small intestine — completes digestion with enzymes, absorbs digested food into the blood. / 小肠——在酶的作用下完成消化，吸收消化后的食物进入血液。
- Large intestine — absorbs water and forms faeces. / 大肠——吸收水分，形成粪便。
- Rectum and anus — store and expel faeces. / 直肠和肛门——储存并排出粪便。
Enzymes are biological catalysts. Amylase breaks down starch into sugars, protease breaks down proteins into amino acids, and lipase breaks down fats into fatty acids and glycerol.
酶是生物催化剂。淀粉酶将淀粉分解为糖，蛋白酶将蛋白质分解为氨基酸，脂肪酶将脂肪分解为脂肪酸和甘油。
6. The Respiratory System | 呼吸系统
Respiration is not the same as breathing. Breathing (ventilation) is the physical movement of air in and out of the lungs, whereas respiration is the chemical release of energy in cells.
呼吸（respiration）不同于喘气呼吸（breathing）。呼吸运动（通气）是空气进出肺部的物理运动，而细胞呼吸是细胞内释放能量的化学过程。
During inhalation, the diaphragm contracts and flattens, and the intercostal muscles raise the ribcage. This increases the volume of the chest, lowering pressure and drawing air into the lungs. During exhalation, these muscles relax, reducing chest volume and pushing air out.
吸气时，横膈膜收缩变平，肋间肌上提胸腔。这增大了胸腔容积，降低了压力，空气被吸入肺部。呼气时，这些肌肉放松，胸腔容积减小，空气被排出。
Gas exchange occurs in the alveoli (tiny air sacs in the lungs). Oxygen diffuses from the air into the blood, and carbon dioxide diffuses from the blood into the air to be exhaled.
气体交换在肺泡（肺部微小的气囊）进行。氧气从空气中扩散到血液里，二氧化碳从血液扩散到空气中被呼出。
7. The Circulatory System | 循环系统
The circulatory system consists of the heart, blood vessels and blood. It transports oxygen, nutrients, hormones and waste products around the body.
循环系统由心脏、血管和血液组成。它将氧气、营养物质、激素和代谢废物运送到全身各处。
The heart is a muscular organ with four chambers: the right atrium, right ventricle, left atrium and left ventricle. The right side pumps deoxygenated blood to the lungs; the left side pumps oxygenated blood to the rest of the body.
心脏是一个有四个腔室的肌性器官：右心房、右心室、左心房和左心室。右侧将缺氧血泵向肺部；左侧将富氧血泵向身体其他部分。
| Blood vessel | Function | 功能 |
| Arteries | Carry blood away from the heart under high pressure | 将血液从心脏运出，压力高 |
| Veins | Return blood to the heart under low pressure, contain valves | 将血液送回心脏，压力低，有静脉瓣 |
| Capillaries | Tiny vessels where exchange of substances occurs | 微小的血管，是物质交换的部位 |
Blood contains red blood cells (carry oxygen using haemoglobin), white blood cells (fight infection), platelets (help clotting) and plasma (liquid that transports dissolved substances).
血液含有红细胞（用血红蛋白携带氧气）、白细胞（抵抗感染）、血小板（帮助凝血）和血浆（运输溶解物质的液体）。
8. Plant Nutrition and Photosynthesis | 植物营养与光合作用
Plants make their own food through photosynthesis. The process uses light energy to convert carbon dioxide and water into glucose and oxygen. Chlorophyll in chloroplasts captures light energy.
植物通过光合作用制造自己的食物。这个过程利用光能，将二氧化碳和水转化为葡萄糖和氧气。叶绿体中的叶绿素捕获光能。
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
The glucose produced is used by the plant for respiration, or it can be converted into starch for storage. Oxygen is released as a by-product into the atmosphere.
生成的葡萄糖被植物用于呼吸作用，或者转化为淀粉储存起来。氧气作为副产品释放到大气中。
The leaf is adapted for photosynthesis: it is broad and flat to absorb light, has veins to carry water and sugars, and contains many stomata (small pores) for gas exchange. Guard cells open and close each stoma to control water loss.
叶片的结构适应光合作用：叶片宽阔扁平以吸收光能，有叶脉运输水分和糖类，并有许多气孔（小孔）用于气体交换。保卫细胞开闭每个气孔以控制水分散失。
9. Reproduction Basics | 生殖基础
Reproduction ensures the continuation of a species. In Year 7 you are introduced to human reproductive organs and the changes that occur during puberty.
生殖保证物种的延续。在七年级，你会初步学习人类生殖器官和青春期发生的变化。
The male reproductive system includes the testes (produce sperm and testosterone) and the penis. The female reproductive system includes the ovaries (produce eggs, oestrogen and progesterone), fallopian tubes, uterus and vagina. During puberty, secondary sexual characteristics develop: growth of body hair, voice deepening in males, and breast development and start of menstruation in females.
男性生殖系统包括睾丸（产生精子和睾酮）和阴茎。女性生殖系统包括卵巢（产生卵细胞、雌激素和孕激素）、输卵管、子宫和阴道。在青春期，第二性征发育：体毛生长、男性声音变低沉，女性乳房发育和月经初潮。
Fertilisation occurs when a sperm fuses with an egg to form a zygote, which can develop into an embryo. This is the start of a new individual.
当精子与卵子融合形成受精卵时便发生了受精，受精卵可以发育成胚胎。这是一个新生命的开端。
Plants also reproduce. The flower contains male parts (stamens that produce pollen) and female parts (carpels containing ovules). Pollination is the transfer of pollen to the stigma, followed by fertilisation and seed formation. Seeds are then dispersed by wind, water or animals to grow in new places.
植物也能生殖。花中包含雄性部分（产生花粉的雄蕊）和雌性部分（含有胚珠的心皮）。传粉是花粉传递到柱头的过程，随后发生受精并形成种子。种子通过风、水或动物散播到新的地方生长。
10. Ecosystems and Food Webs | 生态系统与食物网
An ecosystem is made up of a community of living organisms interacting with their non-living (abiotic) environment. Key terms include habitat (where an organism lives), population (all individuals of one species in an area) and community (all populations in an area).
生态系统由生物群落与其非生物（非生命的）环境相互作用构成。关键术语包括栖息地（生物生活的地方）、种群（某一地区同一物种的全部个体）和群落（某一地区的所有种群）。
mary consumer → secondary consumer → tertiary consumer. For example: grass → rabbit → fox.
能量通过食物链和食物网在生态系统中流动。食物链显示了摄食关系：生产者 → 初级消费者 → 次级消费者 → 三级消费者。例如：草 → 兔 → 狐狸。
Producers (green plants) make their own food by photosynthesis. Consumers eat other organisms. Decomposers (bacteria and fungi) break down dead material, recycling nutrients back into the soil. A food web is a network of interconnected food chains, showing that most organisms eat more than one type of food.
生产者（绿色植物）通过光合作用制造食物。消费者捕食其他生物。分解者（细菌和真菌）分解死去的生物体，将养分循环回土壤中。食物网是相互连接的食物链构成的网络，表明大多数生物不止以一种食物为食。
Organisms are adapted to their environment. Adaptations may be structural (e.g. a camel's hump for fat storage), behavioural (e.g. birds migrating) or physiological. These help organisms survive and reproduce.
生物适应其环境。适应可以是结构上的（如骆驼的驼峰储存脂肪）、行为上的（如鸟类迁徙）或生理上的。这些适应帮助生物生存和繁殖。
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