📚 Year 7 AQA Biology: Core Knowledge Review | AQA 七年级生物：核心知识点梳理
Welcome to our complete revision guide for Year 7 AQA Biology. This article breaks down every essential topic you need to know, from the basic structures of cells and how they form complex systems, to how organisms obtain energy, reproduce and interact with their environment. Use these clear, bilingual explanations to build a strong foundation and boost your confidence for assessments.
欢迎阅读我们为 AQA 七年级生物学准备的完整复习指南。本文梳理了所有核心知识点，从细胞的基本结构和它们如何组成复杂系统，到生物如何获取能量、繁殖以及与环境的相互作用。通过清晰的双语讲解，帮助你打下扎实基础，提升考试的信心。
1. Cells – The Building Blocks of Life | 细胞——生命的基石
All living organisms are made up of cells. The cell theory states that cells are the basic unit of life, all living things consist of one or more cells, and all cells arise from pre-existing cells. A typical animal cell contains a cell membrane that controls what enters and leaves, cytoplasm where chemical reactions occur, a nucleus that holds genetic material and controls the cell, and mitochondria where respiration releases energy.
所有生物体都由细胞构成。细胞学说指出，细胞是生命的基本单位，一切生物都由一个或多个细胞组成，并且所有细胞都来自已有的细胞。一个典型的动物细胞包含控制物质进出的细胞膜、发生化学反应的细胞质、储存遗传物质并控制细胞活动的细胞核，以及进行呼吸作用释放能量的线粒体。
Plant cells share these structures but have three additional key parts: a rigid cell wall made of cellulose that provides support, a large permanent vacuole filled with cell sap that helps keep the cell firm, and chloroplasts that contain chlorophyll to absorb light for photosynthesis. Being able to compare and contrast plant and animal cells is a fundamental skill at this stage.
植物细胞具有以上所有结构，但还多了三个关键部分：由纤维素构成的坚硬的细胞壁提供支撑，充满细胞液的大液泡有助于维持细胞坚挺，以及含有叶绿素的叶绿体吸收光能进行光合作用。能够对比动植物细胞是这个阶段的一项基本技能。
2. Microscopes and Cell Observation | 显微镜与细胞观察
Most cells are too small to be seen with the naked eye, so we use microscopes. A light microscope is the one you will use in Year 7. The eyepiece lens is near your eye and often has a magnification of ×10. The objective lenses fication by the objective magnification. For example, eyepiece ×10 and objective ×40 gives a total magnification of ×400.
大多数细胞太小，肉眼无法看见，因此我们使用显微镜。七年级常使用的是光学显微镜。目镜靠近眼睛，通常放大倍数为10倍。物镜安装在转换器上，一般提供4倍、10倍或40倍的放大倍数。总的放大倍数等于目镜倍数乘以物镜倍数。例如，10倍目镜和40倍物镜组合，总放大倍数为400倍。
To prepare a specimen on a slide, place a thin slice of the sample on a glass slide, add a drop of water or stain (such as iodine to make the nucleus visible), and carefully lower a cover slip at an angle to avoid air bubbles. When drawing what you see under the microscope, always use a sharp pencil, draw clear outlines, label with straight lines, and include the title and magnification.
制作玻片标本时，需将薄切片置于载玻片上，滴一滴水或染色剂（如碘液使细胞核可见），然后将盖玻片呈一定角度缓缓放下以避免气泡。绘制显微镜下所见时，始终用削尖的铅笔画出清晰轮廓，用直线加上标签，并写上标题和放大倍数。
3. Cell Organisation: Tissues, Organs and Systems | 细胞组织：组织、器官和系统
In multicellular organisms, cells are organised into higher levels of structure. A group of similar cells working together to perform a specific function is called a tissue. For example, muscle tissue is made of muscle cells that contract to bring about movement. Different tissues combine to form an organ; the stomach contains muscular tissue to churn food and glandular tissue to produce digestive juices. Organs work together in organ systems the stomach, intestines, liver and other organs form the digestive system. This hierarchy – cells → tissues → organs → organ systems → organism – is a key concept.
在多细胞生物中，细胞按更高的层次组织起来。一群相似的细胞共同完成某项特定功能，被称为组织。例如，肌肉组织由肌细胞组成，通过收缩产生运动。不同的组织组合形成器官；胃包含用来搅拌食物的肌肉组织和产生消化液的上皮组织。器官再协同工作构成器官系统；胃、肠、肝等器官共同形成消化系统。这种细胞→组织→器官→器官系统→生物体的层级关系是一个核心概念。
4. The Skeletal and Muscular Systems | 骨骼与肌肉系统
The human skeleton has several important functions: it supports the body, protects vital organs (e.g. the skull protects the brain, the ribcage protects the heart and lungs), allows movement by providing attachment points for muscles, and produces blood cells in the bone marrow. Bones are connected at joints, which allow different ranges of movement; examples include hinge joints (knee, elbow) and ball-and-socket joints (shoulder, hip).
人体骨骼具有多项重要功能：它支撑身体，保护重要器官（如颅骨保护大脑，胸廓保护心肺），通过为肌肉提供附着点来允许运动，以及在骨髓中生成血细胞。骨与骨在关节处连接，关节允许不同幅度的运动；例子包括屈戌关节（膝、肘）和球窝关节（肩、髋）。
Muscles work in antagonistic pairs because they can only contract and pull – they cannot push. To bend the arm at the elbow, the biceps contracts and shortens while the triceps relaxes and lengthens. To straighten the arm, the triceps contracts and the biceps relaxes. This coordinated action demonstrates how the skeletal and muscular systems work together to produce controlled movement.
肌肉以拮抗对的形式工作，因为它们只能收缩和拉，而不能推。屈起手臂时，肱二头肌收缩变短，肱三头肌舒张变长；伸直手臂时，肱三头肌收缩，肱二头肌舒张。这一协调动作体现了骨骼系统和肌肉系统如何共同产生受控的运动。
5. Nutrition and a Balanced Diet | 营养与均衡饮食
A balanced diet provides all the necessary nutrients in the correct proportions. The main nutrients are carbohydrates (main source of energy), proteins (needed for growth and repair), lipids (fats) (long-term energy store and insulation), vitamins and minerals (required in small amounts for healthy functioning, e.g. vitamin C for skin and gums, calcium for bones and teeth), dietary fibre (keeps the digestive system healthy and prevents constipation), and water (essential for chemical reactions and transport).
均衡饮食以正确的比例提供所有必需的营养素。主要营养素包括：碳水化合物（主要能量来源）、蛋白质（用于生长和修复）、脂质（脂肪）（长期储能和保温隔热）、维生素和矿物质（微量需要但维持健康功能，如维生素C有益皮肤和牙龈，钙有利于骨骼和牙齿）、膳食纤维（保持消化系统健康，预防便秘），以及水（对化学反应和运输至关重要）。
| Nutrient 营养素 | Main Function 主要功能 | Example Food Sources 食物来源举例 |
|---|---|---|
| Carbohydrates | Provide immediate energy | Rice, bread, pasta, potatoes |
| Proteins | Growth and repair of tissues | Meat, fish, eggs, beans |
| Lipids (fats) | Long-term energy storage & insulation | Butter, oil, nuts, cheese |
| Vitamins & Minerals | Healthy body functions | Fruits, vegetables, dairy |
| Dietary fibre | Aids digestion | Wholemeal bread, fruit skins, vegetables |
| Water | Solvent for reactions & transport | Drinks, juicy fruits, soups |
Deficiency diseases can result when a nutrient is lacking. For example, lack of vitamin C causes scurvy, lack of vitamin D or calcium can lead to rickets, and lack of iron results in anaemia. Understanding the role of each nutrient helps us make healthier food choices.
缺乏某种营养素会引发营养缺乏症。例如，缺乏维生素C会导致坏血病，缺乏维生素D或钙可能导致佝偻病，缺铁会造成贫血。了解每种营养素的作用有助于我们做出更健康的食物选择。
6. The Digestive System | 消化系统
The digestive system breaks down large, insoluble food molecules into small, soluble molecules that can be absorbed into the blood. Digestion begins in the mouth where food is chewed and mixed with saliva containing amylase to start breaking down starch. The food then travels down the oesophagus to the stomach, where it is churned with gastric juice containing protease and hydrochloric acid. The small intestine is the main site of digestion and absorption; enzymes from the pancreas and bile from the liver work here. In the large intestine, water is reabsorbed, and the remaining waste is stored as faeces before being egested.
消化系统将大而不溶的食物分子分解成可被血液吸收的小分子。消化始于口腔，食物被咀嚼并混合含有淀粉酶的唾液，开始分解淀粉。然后食物沿食管滑下至胃，在胃里与含有蛋白酶和盐酸的胃液搅拌。小肠是消化和吸收的主要场所；胰脏分泌的酶和肝脏分泌的胆汁在此发挥作用。在大肠中，水分被重吸收，剩余废物以粪便形式临时储存，最终排出体外。
Key digestive enzymes include carbohydrase (amylase) which breaks down starch into glucose, protease which breaks down proteins into amino acids, and lipase which breaks down lipids into fatty acids and glycerol. Absorption of these small molecules occurs mainly across the wall of the small intestine into the bloodstream.
主要的消化酶包括：将淀粉分解成葡萄糖的糖酶（淀粉酶），将蛋白质分解为氨基酸的蛋白酶，以及将脂质分解为脂肪酸和甘油的脂肪酶。这些小分子主要穿过小肠壁被吸收进血液。
7. The Respiratory System and Gas Exchange | 呼吸系统与气体交换
The respiratory system allows oxygen to enter the body and carbon dioxide to be removed. Air enters through the nose or mouth, passes down the trachea, which splits into two bronchi leading into the lungs. Inside the lungs, bronchi divide into smaller bronchioles ending in tiny air sacs called alveoli. The alveoli are surrounded by a network of capillaries, and it is here that gas exchange takes place by diffusion.
呼吸系统使氧气进入体内并排出二氧化碳。空气从鼻或口进入，沿气管下行，气管分成两条支气管通入肺部。在肺内部，支气管一再分支为更小的细支气管，末端是称为肺泡的微小气囊。肺泡周围密布毛细血管网，气体交换就在这里通过扩散进行。
Oxygen diffuses from the high concentration in the alveoli into the low concentration in the blood. At the same time, carbon dioxide diffuses from the blood into the alveoli to be exhaled. The alveoli have several adaptations for efficient exchange: a large surface area, very thin walls (one cell thick), a good blood supply, and a moist lining. The energy released in cells comes from aerobic respiration, summarised by the word equation:
氧气从肺泡中的高浓度扩散到血液中的低浓度。同时，二氧化碳从血液扩散到肺泡中被呼出。肺泡具备多项有利于高效交换的适应性特征：巨大的表面积、极薄的壁（仅一个细胞厚）、良好的血供和湿润的内壁。细胞中释放的能量来源于有氧呼吸，可用文字方程式概括：
glucose + oxygen → carbon dioxide + water (+ energy)
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O (+ energy)
This reaction occurs in mitochondria and provides the energy needed for movement, growth and maintaining body temperature.
该反应在线粒体内进行，为运动、生长和维持体温提供能量。
8. Human Reproduction | 人类生殖
Humans reproduce sexually, producing offspring that inherit a mix of genetic information from both parents. The male reproductive system produces sperm in the testes; sperm travel along the sperm duct and are mixed with fluid from glands to form semen, which is released through the urethra in the penis. The female reproductive system contains ovaries that release eggs approximately every 28 days during the menstrual cycle. The egg travels along the oviduct (fallopian tube) towards the uterus.
人类进行有性生殖，后代继承来自双亲的混合遗传信息。男性生殖系统在睾丸中产生精子；精子经输精管输送，与腺体分泌液混合形成精液，通过阴茎中的尿道排出。女性生殖系统包含卵巢，大约每28天在月经周期中释放一个卵子。卵子沿输卵管向子宫移动。
Fertilisation occurs when a sperm nucleus fuses with the egg nucleus in the oviduct, forming a zygote. The zygote divides many times to become an embryo, which implants into the lining of the uterus. The placenta develops to allow exchange of nutrients, oxygen and waste between the mother's blood and the developing fetus, without mixing the two blood supplies. An amniotic sac filled with fluid protects the fetus. Gestation lasts about 40 weeks before birth.
受精发生在输卵管内，精子的核与卵子核融合，形成受精卵。受精卵经多次分裂成为胚胎，并植入子宫内膜。胎盘发育形成，使得母亲血液和发育中的胎儿之间可以进行营养、氧气和废物的交换，而不会将双方的血液混合。充满液体的羊膜囊保护着胎儿。孕育约40周后分娩。
9. Plant Reproduction and Pollination | 植物生殖与授粉
Flowers are the reproductive organs of many plants. The male part, the stamen, consists of an anther that produces pollen grains and a filament that holds it up. The female part, the carpel, consists of a sticky stigma to catch pollen, a style, and an ovary containing ovules. Pollination is the transfer of pollen from the anther to the stigma. This can be carried out by wind, insects, or other animals, and plant structure often reflects the pollination method.
花是许多植物的生殖器官。雄性部分是雄蕊，由产生花粉粒的花药和支撑它的花丝组成。雌性部分是雌蕊，由粘性的柱头接获花粉、花柱和含有胚珠的子房构成。授粉是指花粉从花药传送到柱头的过程，可通过风、昆虫或其他动物完成，植物的形态往往反映出其授粉方式。
After pollination, a pollen tube grows down the style into the ovary, and the male nucleus fuses with the female nucleus inside the ovule – this is fertilisation. The fertilised ovule develops into a seed, and the ovary wall becomes the fruit. Seeds can be dispersed by wind (e.g. dandelion), by animals (e.g. burdock hooks or fleshy fruits eaten and later excreted), or by self-explosion (e.g. pea pods), increasing the chances of survival.
授粉后，花粉管沿花柱向下生长进入子房，雄核与胚珠内的雌核融合，这就是受精。受精后的胚珠发育为种子，子房壁发育成果实。种子可通过风（如蒲公英）、动物（如牛蒡的钩刺，或动物食用多汁果实后再排出）、或自身弹射（如豌豆荚）等方式传播，从而提高存活机会。
10. Ecosystems and Food Webs | 生态系统与食物链
An ecosystem is made up of a community of living organisms interacting with their non-living environment. A habitat is where an organism lives, a population is all the members of one species in a habitat, and a community is all the populations of different species living together. In every ecosystem, energy enters through producers – usually plants and algae that photosynthesise. Consumers eat other organisms: primary consumers eat producers, secondary consumers eat primary consumers, and so on.
生态系统由生物群落及其与非生物环境的相互作用构成。栖息地是生物居住的地方，种群是同一物种在一个栖息地的所有个体，群落是指不同物种的所有种群共同生活在一起。在每一个生态系统中，能量通过生产者（通常是进行光合作用的植物和藻类）进入系统。消费者则取食其他生物：初级消费者吃生产者，次级消费者吃初级消费者，以此类推。
nergy flow, for example: grass → rabbit → fox. Food chains can be interconnected to form a food web, which gives a more realistic picture of feeding relationships. Some organisms, such as bacteria and fungi, act as decomposers, breaking down dead matter and recycling nutrients. Additionally, bioaccumulation can occur when toxins (e.g. pesticides) build up as they move along a food chain, reaching harmful concentrations in top predators.
食物链展示能量流动的单一路径，例如：草 → 兔 → 狐。食物链相互交织构成食物网，更能反映真实的取食关系。有些生物如细菌和真菌充当分解者，分解死去的生物并循环利用养分。此外，当毒素（如杀虫剂）沿食物链传递并富集时，会发生生物累积，导致顶级捕食者体内毒素浓度达到有害水平。
11. Adaptation and Competition | 适应与竞争
Every organism has features – adaptations – that allow it to survive in its environment. Adaptations can be structural (physical features, like a camel's hump storing fat, not water, for energy and metabolic water), behavioural (how an animal acts, such as dormancy or migration), or physiological (internal body processes). For example, a cactus has thick fleshy stems to store water, spines to reduce water loss and defend against herbivores, and extensive shallow roots to capture rainfall quickly.
每种生物都具有使其能在环境中生存的特征，即适应。适应可以是结构上的（如骆驼的驼峰储存脂肪以提供能量和代谢水，而非直接储水）、行为上的（如休眠或迁徙）或生理上的（体内过程）。例如，仙人掌有多汁的茎储水，叶变为刺以减少水分流失并防御动物取食，还有伸展广泛的浅根以迅速捕获雨水。
Within any habitat, organisms compete for limited resources. Animals may compete for food, mates and territory. Plants compete for light, space, water and mineral ions from the soil. Competition can be intraspecific (within the same species) or interspecific (between different species). A successful species possesses a combination of adaptations that enable it to survive, reproduce and outcompete others in its niche.
在任何栖息地中，生物都会为有限的资源而竞争。动物可能竞争食物、配偶和领地。植物则竞争光、空间、水分和土壤中的矿物质离子。竞争可以是种内竞争（同一物种内）或种间竞争（不同物种间）。成功的物种拥有一整套适应特征，使其能够在所处的生态位中生存、繁殖并在竞争中胜出。
12. Health, Drugs and Disease | 健康、药物与疾病
Being healthy is more than just not being ill; it is a state of complete physical, mental and social well-being. A poor diet can lead to health problems: too much sugar and fat can cause obesity and related issues such as type 2 diabetes, while deficiencies in essential nutrients lead to conditions like kwashiorkor (protein deficiency) or rickets. Regular exercise helps maintain a healthy heart, lung function and mental health.
健康不仅仅是不生病，它是身体、心理和社会适应的完好状态。不良饮食可导致健康问题：过多糖和脂肪会导致肥胖以及相关疾病如2型糖尿病，而必需营养素的缺乏则引发夸希奥科病（蛋白质缺乏症）或佝偻病等。定期锻炼有助于维持心脏、肺部功能和心理健康。
Lifestyle choices also have major impacts. Smoking damages cells lining the trachea and lungs, leads to emphysema, and greatly increases the risk of lung cancer and heart disease. Alcohol narrows reaction times, harms the liver, and can lead to addiction. Recreational drugs can alter mood or behaviour and may cause health and social problems. Diseases can be communicable Published by TutorHao | Year 7 Biology Revision Series | aleveler.com
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