📚 Year 7 SQA Biology: Core Knowledge Overview | SQA 七年级生物：核心知识点梳理
Welcome to your essential revision guide for Year 7 SQA Biology. This article brings together all the key concepts you need to master, from the building blocks of life to the complex relationships in ecosystems. We have structured each topic as a clear bilingual reference, so you can strengthen your understanding in both English and Chinese while preparing confidently for assessments.
欢迎来到 SQA 七年级生物核心知识点梳理。本文汇集了你需要掌握的所有关键概念，从生命的基本单位到生态系统中复杂的相互关系。我们将每个主题整理成清晰的中英双语对照，帮助你在备考时同时强化英文和中文的理解，自信迎接每一次测评。
1. Characteristics of Living Things | 生物的基本特征
All living organisms share a set of common characteristics that distinguish them from non-living matter. The acronym MRS GREN helps us remember these life processes: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion and Nutrition. A car may move and use fuel, but it cannot grow or reproduce, so it is not alive.
所有生物都具有一系列共同特征，这些特征将它们与非生命物质区分开来。我们可以用缩写 MRS GREN 来记忆这些生命活动：运动、呼吸、感应、生长、繁殖、排泄和营养。一辆汽车虽然可以移动并使用燃料，但它无法生长或繁殖，因此它不是生物。
- Movement: Changing position or moving parts of the body. / 运动：改变位置或移动身体部位。
- Respiration: Releasing energy from food. / 呼吸：从食物中释放能量。
- Sensitivity: Detecting and responding to changes in the environment. / 感应：探测环境变化并作出反应。
- Growth: Increasing in size and complexity. / 生长：体积增大、结构变复杂。
- Reproduction: Producing offspring. / 繁殖：产生后代。
- Excretion: Removing metabolic waste products. / 排泄：清除代谢产生的废物。
- Nutrition: Taking in and using food materials. / 营养：摄取和利用食物。
2. Cells: The Building Blocks of Life | 细胞：生命的基本单位
Cells are the smallest units of life. Every living organism is made up of one or more cells. The two main types are animal cells and plant cells, and they share some structures but also have important differences. Plant cells contain a rigid cell wall, a large permanent vacuole, and chloroplasts for photosynthesis, while animal cells do not.
细胞是生命的最小单位。每一个生物体都由一个或多个细胞构成。细胞主要分为动物细胞和植物细胞两大类，它们有一些共同的结构，但也存在重要区别。植物细胞含有坚硬的细胞壁、一个占细胞大部分体积的液泡以及进行光合作用的叶绿体，而动物细胞则没有这些结构。
| Structure / 结构 | Animal Cell / 动物细胞 | Plant Cell / 植物细胞 |
|---|---|---|
| Cell membrane / 细胞膜 | Present / 有 | Present / 有 |
| Cytoplasm / 细胞质 | Present / 有 | Present / 有 |
| Nucleus / 细胞核 | Present / 有 | Present / 有 |
| Mitochondria / 线粒体 | Present / 有 | Present / 有 |
| Cell wall / 细胞壁 | Absent / 无 | Present (made of cellulose) / 有（由纤维素构成） |
| Chloroplasts / 叶绿体 | Absent / 无 | Present / 有 |
| Vacuole / 液泡 | Small, temporary / 小而临时 | Large, permanent / 大而永久 |
3. Levels of Organisation | 生物体的结构层次
Living organisms are organised from the simplest level to the most complex. In multicellular organisms, cells that perform the same function group together to form tissues. Different tissues work together to form organs, and organs work together in organ systems. A leaf is an organ made of epidermal, mesophyll and vascular tissues, all coordinating for photosynthesis.
生物体从简单到复杂有着严格的结构层次。在多细胞生物中，执行相同功能的细胞聚集在一起形成组织。不同的组织协同工作形成器官，而器官又共同构成器官系统。一片叶子就是一个器官，它由表皮组织、叶肉组织和维管组织共同构成，协调完成光合作用。
- Cells / 细胞 → Tissues / 组织 → Organs / 器官 → Organ Systems / 器官系统 → Organism / 生物体
- Example in humans: muscle cell → muscle tissue → stomach → digestive system → human / 人体示例：肌肉细胞 → 肌肉组织 → 胃 → 消化系统 → 人体
4. The Skeletal and Muscular Systems | 骨骼与肌肉系统
The human skeleton provides support, protects delicate organs, allows movement and produces blood cells in the bone marrow. Bones are attached to muscles by tendons, while bones are connected to other bones by ligaments. Muscles can only contract (pull), so they always work in antagonistic pairs. When the biceps contracts to bend the arm, the triceps relaxes; to straighten the arm, the triceps contracts and the biceps relaxes.
人体骨骼提供支撑、保护脆弱器官、实现运动并在骨髓中制造血细胞。骨骼通过肌腱与肌肉相连，而骨与骨之间则由韧带连接。肌肉只能收缩（拉动），因此它们总是以拮抗肌对的形式工作。当肱二头肌收缩使手臂弯曲时，肱三头肌放松；要使手臂伸直，肱三头肌收缩而肱二头肌放松。
5. Nutrition and a Balanced Diet | 营养与均衡膳食
A balanced diet contains the correct proportions of carbohydrates, proteins, lipids (fats), vitamins, minerals, dietary fibre and water. Each nutrient plays a specific role in the body. Carbohydrates provide the main source of quick energy, proteins are needed for growth and repair of tissues, and lipids provide long-term energy storage and insulation.
均衡的膳食包含适当比例的碳水化合物、蛋白质、脂类、维生素、矿物质、膳食纤维和水。每种营养素在身体中都扮演着特定的角色。碳水化合物是快速供能的主要来源，蛋白质用于组织的生长和修复，而脂类则提供长期的能量储存和隔热保温功能。
- Carbohydrates / 碳水化合物: bread, pasta, rice; provides energy / 面包、意大利面、米饭；提供能量
- Proteins / 蛋白质: meat, beans, eggs; builds and repairs tissues / 肉类、豆类、鸡蛋；构建和修复组织
- Lipids / 脂类: butter, oil; energy store and insulation / 黄油、食用油；储存能量并隔热
- Vitamins and minerals / 维生素和矿物质: fruits, vegetables; keep body processes working / 水果、蔬菜；维持身体功能正常运转
- Fibre / 膳食纤维: whole grains; prevents constipation / 全谷物；防止便秘
- Water / 水: essential for all chemical reactions in cells / 对细胞内所有化学反应都至关重要
6. The Digestive System | 消化系统
Digestion is the process of breaking down large, insoluble food molecules into small, soluble molecules that can be absorbed into the bloodstream. Mechanical digestion, such as chewing in the mouth, physically breaks food into smaller pieces. Chemical digestion uses enzymes to break down specific nutrients: amylase breaks down starch into sugar in the mouth and small intestine.
消化是将大的、不溶性的食物分子分解为可以吸收进入血液的小分子可溶性物质的过程。物理性消化，例如口腔中的咀嚼，将食物物理性地分解为更小的碎块。化学性消化利用酶来分解特定的营养物质：淀粉酶在口腔和小肠中将淀粉分解为糖。
| Organ / 器官 | Function / 功能 |
|---|---|
| Mouth / 口腔 | Chewing, starch digestion begins / 咀嚼，淀粉开始消化 |
| Stomach / 胃 | Churns food, acid kills bacteria, protease digests protein / 搅拌食物，胃酸杀菌，蛋白酶消化蛋白质 |
| Small intestine / 小肠 | Digestion completes, nutrients are absorbed / 完成消化，吸收营养物质 |
| Large intestine / 大肠 | Absorbs water, forms faeces / 吸收水分，形成粪便 |
7. Breathing and the Respiratory System | 呼吸与呼吸系统
Breathing is the physical process of moving air into and out of the lungs. During inhalation, the diaphragm contracts and moves downward, and the intercostal muscles lift the rib cage up and out. This increases the volume of the chest cavity, reducing pressure so air rushes into the lungs. Gas exchange occurs in the alveoli, where oxygen moves into the blood and carbon dioxide moves out by diffusion.
呼吸是将气体吸入和排出肺部的物理过程。吸气时，膈肌收缩并向下移动，肋间肌将肋骨向上向外提升。这增大了胸腔的容积，降低了气压，使空气涌入肺部。气体交换发生在肺泡中，氧气通过扩散进入血液，二氧化碳则通过扩散排出体外。
- Inhaled air: about 21% oxygen, 0.04% carbon dioxide / 吸入的气体：约 21% 氧气，0.04% 二氧化碳
- Exhaled air: about 16% oxygen, 4% carbon dioxide / 呼出的气体：约 16% 氧气，4% 二氧化碳
- The alveoli have thin walls (one cell thick) and a large surface area to speed up diffusion. / 肺泡壁极薄（仅一个细胞厚度）且表面积巨大，可以加速气体扩散。
8. 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. The heart is a muscular pump with four chambers. The right side pumps deoxygenated blood to the lungs, while the left side pumps oxygenated blood to the rest of the body. Arteries carry blood away from the heart under high pressure, and veins carry blood back toward the heart at lower pressure, with valves to prevent backflow.
循环系统由心脏、血管和血液组成，负责将氧气、营养物质、激素和废物运送到全身各处。心脏是一个由肌肉构成的泵，共有四个腔室。右心室将缺氧血泵送至肺部，而左心室将富氧血泵送至身体其余部分。动脉将血液在高压下带离心脏，静脉则在较低压下将血液送回心脏，并带有静脉瓣以防止倒流。
9. Reproduction in Humans | 人类的生殖
Reproduction is the process that produces offspring, ensuring the continuation of a species. In humans, sexual reproduction involves the fusion of a male gamete (sperm) and a female gamete (egg) during fertilisation to form a zygote. The male reproductive system produces sperm in the testes, while the female reproductive system releases eggs from the ovaries approximately once every 28 days during the menstrual cycle.
生殖是产生后代的过程，确保物种得以延续。人类的生殖属于有性生殖，涉及雄配子（精子）与雌配子（卵子）在受精过程中融合形成受精卵。男性生殖系统在睾丸中产生精子，而女性生殖系统大约每 28 天在月经周期中从卵巢排出一枚卵子。
After fertilisation, the zygote implants in the lining of the uterus. The placenta forms, allowing exchange of nutrients, oxygen and waste between mother and fetus without mixing their blood. The amniotic fluid acts as a shock absorber to protect the developing baby.
受精后，受精卵植入子宫内膜。随后形成胎盘，允许母亲与胎儿之间交换营养物质、氧气和废物，但双方的血液不会混合。羊水则起到减震器的作用，保护发育中的胎儿。
10. Photosynthesis: How Plants Make Food | 光合作用：植物如何制造养分
Photosynthesis is the process by which green plants use light energy to convert carbon dioxide and water into glucose and oxygen. This process takes place in the chloroplasts, which contain the green pigment chlorophyll that absorbs sunlight. The word equation for photosynthesis is:
光合作用是绿色植物利用光能，将二氧化碳和水转化为葡萄糖和氧气的过程。这一过程发生在叶绿体中，叶绿体含有绿色色素叶绿素，可以吸收太阳光。光合作用的文字方程式为：
Carbon dioxide + Water → Glucose + Oxygen
二氧化碳 + 水 → 葡萄糖 + 氧气
The rate of photosynthesis is affected by the availability of light intensity, carbon dioxide concentration and temperature. If any one of these factors is in short supply, it becomes the limiting factor that slows down the whole process. Plants use the glucose produced for respiration, to make cellulose for cell walls, and to store as starch.
光合作用的速率受光照强度、二氧化碳浓度和温度的共同影响。如果其中任何一个因素供应不足，它就会成为限制因子，减慢整个过程的速率。植物将产生的葡萄糖用于呼吸作用、制造细胞壁所需的纤维素，以及以淀粉的形式储存起来。
11. Ecosystems, Habitats and Food Chains | 生态系统、栖息地与食物链
An ecosystem is a community of living organisms interacting with each other and their non-living environment. A habitat is the specific place where an organism lives, providing the food, shelter and conditions it needs to survive. In any ecosystem, energy flows from the sun to producers (plants) and then to consumers (animals). A food chain shows this linear feeding relationship.
生态系统是由生物群落与其周围非生物环境相互作用而形成的统一整体。栖息地是某种生物生活的具体地点，为其提供生存所需的食物、居所和条件。在任何生态系统中，能量从太阳流向生产者（植物），再传递给消费者（动物）。食物链显示了这种线性的捕食关系。
- A simple food chain: grass → grasshopper → frog → hawk / 一条简单的食物链：草 → 蚱蜢 → 青蛙 → 鹰
- Producers make their own food; consumers eat other organisms. / 生产者自己制造食物；消费者以其他生物为食。
- Predators kill and eat prey; the population sizes of predator and prey are interdependent. / 捕食者捕杀并吃掉猎物；两者的种群数量相互依存。
12. Microbiology and Food Chains | 微生物与食物链
Not all organisms can be seen with the naked eye. Microorganisms, including bacteria, fungi and viruses, are everywhere. Many are helpful, such as bacteria used in making yoghurt and fungi used in baking bread, but some cause disease. In food webs, decomposers such as bacteria and fungi break down dead organic matter, returning valuable nutrients to the soil for producers to use again.
并非所有生物都能用肉眼看到。微生物，包括细菌、真菌和病毒，遍布各个角落。许多微生物是有益的，比如用于制作酸奶的细菌和用于烘焙面包的真菌，但也有一些会导致疾病。在食物网中，细菌和真菌等分解者将死亡的有机物质分解，使宝贵的养分回归土壤，供生产者再次利用。
When studying microorganisms safely in the lab, we use agar plates and follow strict aseptic techniques to prevent contamination by unwanted microbes. This ensures we are only growing the organism we intend to investigate.
在实验室安全地研究微生物时，我们使用琼脂平板并遵循严格的无菌操作技术，以防止不需要的微生物污染。这确保了只有我们想要研究的微生物能够生长。
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