📚 Year 7 AQA Biology: Summer Preview and Bridging Course | Year 7 AQA 生物：暑期预习与衔接课程
Welcome to the exciting world of Year 7 AQA Biology! This summer programme is designed to help you make a smooth transition from primary science to the more focused and detailed study of biology at secondary level. You will revisit topics you may have touched on before, like life processes, cells and habitats, but now you will dig deeper into how living organisms function, how cells carry out their jobs, and how all living things are connected through feeding relationships and ecosystems. Along the way you will also build the practical skills that AQA examiners and teachers look for: using a microscope, planning a fair test, recording data in tables, drawing graphs and writing clear conclusions. By the end of this preview you will feel confident, curious and ready to start Year 7 with a head start in key biological concepts and scientific skills.
欢迎来到精彩的七年级 AQA 生物世界！这个暑期课程旨在帮助你从小学科学顺利过渡到中学阶段更聚焦、更深入的生物学习。你将重温之前可能接触过的主题，如生命过程、细胞和栖息地，但这一次你会更深入地探索生物体的运作方式、细胞如何完成各自的任务，以及所有生物如何通过取食关系和生态系统彼此相连。在此过程中，你还将建立 AQA 考官和老师所看重的实验技能：使用显微镜、设计公平实验、用表格记录数据、绘制图表并写出清晰的结论。完成这次预习后，你将充满信心与好奇心，带着关键生物学概念和科学技能的领先优势开始七年级的学习。
1. Introduction to Year 7 Biology | 七年级生物入门
In Year 7, biology is all about understanding living organisms and the life processes that keep them alive. The biggest change from primary school is that you will shift from simply describing what you see to explaining why things happen. Instead of writing "the plant grew", you will be expected to ask what made it grow, how you could measure the growth, and how you could be sure your result was reliable.
在七年级，生物学的核心是理解生物体以及维持其生存的生命活动。与小学相比最大的变化是：你将从单纯描述所见，转向解释现象背后的原因。你不再只是写"植物长高了"，而要学会追问是什么让它生长、你如何测量这种生长、又如何确信自己的结果是可靠的。
AQA biology lessons are hands-on and encourage you to ask questions, make predictions, and design fair tests. You will learn to use a microscope, collect data in tables, and present your findings clearly using graphs and scientific vocabulary. You will also learn that science is a process of checking and improving ideas, not just memorising facts.
AQA 生物课注重动手实践，鼓励你提出问题、作出预测并设计公平实验。你将学会使用显微镜、用表格收集数据，并借助图表和科学术语清晰地展示发现成果。你还会明白：科学是一个不断检验和改进观点的过程，而不仅仅是背诵事实。
This transition may seem big, but remember - every great scientist started with curiosity, just like you. Keep a small notebook over the summer and write down every biological question that pops into your head. Questions are the raw material of good science.
这个转变也许看起来很大，但请记住——每一位伟大的科学家都始于好奇心，就如同你一样。暑期准备一个小本子，把脑海里冒出的每一个生物学问题记下来。问题正是好科学的原材料。
2. Living or Non-living? MRS GREN | 生物与非生物？生命活动的七大特征
The first big question in biology is: how do we know if something is alive? Scientists use a helpful memory aid called MRS GREN. Each letter stands for one life process, and all living organisms carry out all seven processes at some point in their lives.
生物学的第一个大问题是：我们怎么知道某样东西是活的？科学家使用一个便于记忆的口诀 MRS GREN。每个字母代表一种生命活动，而所有生物在其生命中的某个阶段都会进行全部七种生命活动。
| Letter 字母 | Life process 生命活动 | Example 例子 |
| M | Movement 运动 | A cheetah running; a shoot bending towards light 猎豹奔跑；幼苗向光弯曲 |
| R | Respiration 呼吸作用 | Releasing energy from glucose in every cell 每个细胞从葡萄糖中释放能量 |
| S | Sensitivity 应激性 | A pupil narrowing in bright light 强光下瞳孔缩小 |
| G | Growth 生长 | A seedling getting taller and heavier 幼苗变得更高更重 |
| R | Reproduction 繁殖 | A sunflower making seeds 向日葵结出种子 |
| E | Excretion 排泄 | Removing carbon dioxide through the lungs 通过肺排出二氧化碳 |
| N | Nutrition 营养 | Eating food, or photosynthesising 摄食，或进行光合作用 |
A car moves, uses fuel and gives out waste, but it does not grow, reproduce or respond on its own - so it is not alive. A flame also "moves" and "consumes fuel", yet it shows none of the other processes. Use all seven letters, not just one, before you decide.
汽车会移动、消耗燃料并排放废物，但它不会生长、繁殖，也不能自主作出反应——所以它不是生物。火焰也会"移动"和"消耗燃料"，却不具备其他任何特征。下结论前要检查全部七个字母，而不是只看一个。
Two tricky cases come up again and again in tests. Seeds and spores look lifeless but are dormant, meaning they are alive but inactive until conditions improve. Viruses are a grey area: they reproduce and have genetic material, but they cannot respire or grow on their own, so many scientists describe them as being on the border between living and non-living.
考试中反复出现两个棘手案例。种子和孢子看起来毫无生机，但它们处于休眠状态，即依然活着，只是条件改善前不活跃。病毒属于灰色地带：它们能繁殖并拥有遗传物质，却无法独立呼吸或生长，因此许多科学家把它们描述为介于生物与非生物之间的存在。
3. Cells: The Building Blocks of Life | 细胞：生命的基石
All living organisms are made of cells. Some organisms, like bacteria and amoeba, are unicellular - a single cell carries out every life process. Others, including humans, oak trees and earthworms, are multicellular, meaning billions of cells work together, often organised into tissues, organs and organ systems.
所有生物都由细胞构成。细菌、变形虫等生物是单细胞的——单个细胞就完成全部生命活动。而人类、橡树和蚯蚓等属于多细胞生物，意味着数以亿计的细胞协同工作，通常组织成组织、器官和器官系统。
Animal and plant cells share several key structures. The cell membrane controls what enters and leaves the cell. The cytoplasm is a jelly-like substance where most chemical reactions happen. The nucleus contains the genetic material and controls the cell's activities. Mitochondria are the site of respiration and release energy, while ribosomes are where proteins are built.
动物细胞与植物细胞共有几个关键结构。细胞膜控制物质进出细胞。细胞质是胶状物质，大多数化学反应在此发生。细胞核含有遗传物质并控制细胞的活动。线粒体是呼吸作用的场所并释放能量，核糖体则是合成蛋白质的地方。
Plant cells have three extra structures that animal cells do not have. A cell wall made of cellulose gives the cell a fixed shape and support. Chloroplasts contain chlorophyll and absorb light energy for photosynthesis. A permanent vacuole filled with cell sap helps keep the cell firm and stores dissolved substances.
植物细胞还有三种动物细胞所没有的结构。由纤维素构成的细胞壁为细胞提供固定形状和支撑。叶绿体含有叶绿素，吸收光能用于光合作用。充满细胞液的中央液泡帮助细胞保持坚挺，并储存溶解的物质。
Animal cell 动物细胞: membrane + cytoplasm + nucleus + mitochondria + ribosomes
Plant cell 植物细胞: all of the above + cell wall + chloroplasts + permanent vacuole
Cells become specialised to do a particular job. A red blood cell has no nucleus so there is more room for haemoglobin. A nerve cell is long so it can carry electrical impulses over a distance. A root hair cell has a long, thin extension that increases the surface area for absorbing water and mineral ions. A sperm cell has a tail so it can swim to the egg.
细胞会分化以完成特定任务。红细胞没有细胞核，从而为血红蛋白腾出更多空间。神经细胞很长，可以把电信号传递到较远距离。根毛细胞有细长的突起，增大表面积以吸收水分和矿物质离子。精子细胞有尾部，因而能游向卵细胞。
4. Using a Microscope Safely and Correctly | 安全正确地使用显微镜
epiece lens of ×10 and three objective lenses, usually ×4, ×10 and ×40, mounted on a rotating nosepiece. The stage holds the slide, clips keep it steady, and the coarse and fine focussing wheels bring the image into sharp view.
显微镜是细胞生物学中最重要的工具，七年级正是学会正确使用它的阶段。典型的学生用光学显微镜配有 ×10 的目镜，以及通常为 ×4、×10、×40 的三个物镜，安装在可旋转的物镜转换器上。载物台放置玻片，压片夹固定玻片，粗准焦螺旋和细准焦螺旋使物像变得清晰。
To work out how much bigger the specimen looks, multiply the eyepiece magnification by the objective magnification. Always start with the lowest power objective, focus with the coarse wheel, then move to a higher power and refocus using only the fine wheel.
要计算标本被放大的倍数，用目镜放大倍数乘以物镜放大倍数。始终从最低倍物镜开始，用粗准焦螺旋调焦，然后换到高倍物镜，并且只用细准焦螺旋重新调焦。
Total magnification 总放大倍数 = eyepiece 目镜 × objective 物镜
×10 × ×40 = ×400
To prepare a slide, place the specimen on a clean slide, add a drop of water, then lower a coverslip at an angle using a mounted needle. This avoids trapping air bubbles, which appear as thick black circles and are often mistaken for cells. For onion epidermis you may add iodine solution to stain the nucleus so it stands out.
制作玻片时，把标本放在干净的载玻片上，滴一滴水，再用解剖针以一定角度斜放下盖玻片。这样可以避免夹入气泡——气泡呈现为粗黑圆圈，常被误认为细胞。观察洋葱表皮时，可加碘液对细胞核染色，使其更明显。
Scientific drawings have their own rules. Use a sharp pencil, draw only what you can see, keep the drawing large and unshaded, use single clear lines, and add straight label lines that do not cross. Always write the title and the total magnification underneath. When you finish, switch off the lamp, lower the stage and return the lowest power objective as a courtesy to the next user.
科学绘图有自己的规则。使用削尖的铅笔，只画你实际看到的内容，图像要大且不加阴影，使用清晰的单线，并加上互不交叉的直线标注线。图下务必写明标题与总放大倍数。使用结束后，关掉光源、降低载物台并把物镜转回最低倍，方便下一位使用者。
5. Classification and Dichotomous Keys | 分类与二歧检索表
Biologists have named and grouped around two million species, and classification makes that huge variety manageable. Organisms are sorted into groups based on shared features, from the broadest level (kingdom) down to the most specific (species). The order is kingdom, phylum, class, order, family, genus, species.
生物学家已命名并归类约两百万个物种，分类让如此庞大的多样性变得易于管理。生物依据共同特征被归入不同类群，从最宽泛的层级（界）一直到最具体的层级（种）。顺序为：界、门、纲、目、科、属、种。
Carl Linnaeus introduced the binomial system, in which every species has a two-part Latin name: the genus (capitalised) followed by the species (lower case), both written in italics. Homo sapiens, Panthera leo and Quercus robur are three familiar examples. The genus name is shared by close relatives; the species name is unique to that organism.
卡尔·林奈提出了双名法，每个物种都有一个由两部分组成的拉丁学名：属名（首字母大写）加种名（全小写），且全部用斜体书写。Homo sapiens、Panthera leo 和 Quercus robur 是三个熟悉的例子。属名由近亲共享，种名则专属于该生物。
The five kingdoms most often used at this level are animals, plants, fungi, protoctists and prokaryotes (bacteria). Fungi are easily confused with plants, but they have no chlorophyll, feed by absorbing nutrients from dead material, and have cell walls made of chitin rather than cellulose.
这一阶段最常使用的五界是动物界、植物界、真菌界、原生生物界和原核生物界（细菌）。真菌容易被误认为植物，但它们没有叶绿素，通过从死亡物质中吸收养分来取食，细胞壁由几丁质而非纤维素构成。
A dichotomous key is a series of paired questions that leads you to a name for an unfamiliar organism. Each step offers two choices, and only one is correct at each level. Good keys use visible, measurable features such as "has wings" or "leaves are needle-shaped", not vague descriptions like "looks big".
二歧检索表是一组成对的问题，引导你为陌生生物确定名称。每一步给出两个选项，每一层级只有一个正确。好的检索表使用可见、可测量的特征，例如"有翅"或"叶呈针形"，而不是"看起来很大"这类模糊描述。
6. Habitats, Ecosystems and Food Chains | 栖息地、生态系统与食物链
An ecosystem is the community of organisms in an area together with all the non-living conditions they interact with. The habitat is the place where an organism lives, for example a pond, a hedgerow or a rock pool. The population is all the organisms of one species in that area, and the community is all the populations of different species living there.
生态系统是指某一区域内的生物群落，以及它们相互作用的所有非生物条件。栖息地是生物生活的地方，例如池塘、灌木篱或潮池。种群是该区域内同一物种的全部个体，而群落则是生活在其中的所有不同物种的种群总和。
A food chain always starts with a producer, which is almost always a green plant or alga that makes its own food by photosynthesis. The arrows show the direction in which energy is transferred, so they point from the organism being eaten to the organism that eats it.
食物链总是从生产者开始，通常是能通过光合作用自己制造食物的绿色植物或藻类。箭头表示能量转移的方向，因此箭头由被吃的生物指向取食它的生物。
grass → grasshopper → frog → snake 草 → 蚱蜢 → 青蛙 → 蛇
Organisms in a food chain are described by their feeding position: primary consumer, secondary consumer and tertiary consumer. When many food chains in a habitat are linked together, they form a food web. A change in one population can then ripple through the whole web, which is why removing an apex predator often damages an ecosystem.
食物链中的生物按其取食位置被描述为初级消费者、次级消费者和三级消费者。当栖息地中的多条食物链相互连接，就形成食物网。一个种群的变化会波及整个食物网，这也是移除顶级捕食者往往破坏生态系统的原因。
Energy is lost at every stage: about 90% is lost as heat from respiration, in movement, and in undigested material such as bones and fur. Only around 10% passes to the next level, which is why food chains rarely have more than four or five links.
能量在每一环节都会损失：约 90% 以呼吸产热、运动和骨骼皮毛等未消化物质的形式散失，只有大约 10% 传递到下一营养级，这就是食物链通常不超过四到五个环节的原因。
7. Nutrition and Photosynthesis | 营养与光合作用
Plants are autotrophs - they make their own food. Photosynthesis uses light energy to convert carbon dioxide and water into glucose and oxygen, in the presence of chlorophyll inside chloroplasts.
植物是自养生物——它们自己制造食物。光合作用利用光能，在叶绿体中的叶绿素参与下，把二氧化碳和水转化为葡萄糖和氧气。
carbon dioxide + water → glucose + oxygen 二氧化碳 + 水 → 葡萄糖 + 氧气
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
The rate of photosynthesis is affected by limiting factors: light intensity, carbon dioxide concentration, temperature and the amount of chlorophyll. Increase the factor that is in shortest supply and the rate rises; increase any other factor and nothing changes. Above roughly 40 °C the enzymes controlling the reaction are denatured, so the rate falls sharply.
光合作用的速率受限制因子影响：光照强度、二氧化碳浓度、温度和叶绿素含量。增加供应最不足的那个因子，速率会上升；增加其他任何因子都不会有变化。超过约 40 °C 后，控制反应的酶变性，速率会急剧下降。
Plants also need mineral ions from the soil. Nitrate ions are needed to make proteins and DNA, so a shortage causes stunted growth and yellowing leaves. Magnesium ions are needed to make chlorophyll, so a shortage causes yellow leaves too, but from the older leaves first.
植物还需要从土壤中获取矿物质离子。硝酸根离子用于制造蛋白质和 DNA，缺乏时会导致生长迟缓、叶片发黄。镁离子用于合成叶绿素，缺乏时同样叶片发黄，但最先从老叶开始。
Humans are heterotrophs and need a balanced diet containing carbohydrates, proteins, lipids, vitamins, minerals, fibre and water. The main food tests you should know are: iodine solution for starch (blue-black), Benedict's solution for reducing sugars (brick-red on heating), ethanol and water for lipids (white emulsion), and Biuret reagent for protein (purple).
人类是异养生物，需要含有碳水化合物、蛋白质、脂质、维生素、矿物质、膳食纤维和水的均衡膳食。需掌握的主要食物检测有：碘液检测淀粉（蓝黑色）、本尼迪特试剂检测还原糖（加热后砖红色）、乙醇加水检测脂质（白色乳浊液）、双缩脲试剂检测蛋白质（紫色）。
8. Respiration and Gas Exchange | 呼吸作用与气体交换
Respiration is not the same as breathing. Respiration is a chemical reaction that takes place in every living cell, releasing the energy stored in glucose so it can be used for growth, movement, keeping warm and active transport.
呼吸作用与呼吸不是同一回事。呼吸作用是发生在每一个活细胞中的化学反应，它释放储存在葡萄糖中的能量，供生长、运动、维持体温和主动运输使用。
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy
Aerobic respiration uses oxygen and releases a lot of energy per glucose molecule. Anaerobic respiration happens when oxygen is in short supply. In human muscle cells glucose is converted into lactic acid, which builds up and causes cramp and muscle fatigue. In yeast, anaerobic respiration produces ethanol and carbon dioxide, which is why yeast is used in breadmaking and brewing.
有氧呼吸需要氧气，每分子葡萄糖释放大量能量。无氧呼吸在氧气供应不足时发生。在人体肌细胞中，葡萄糖转化为乳酸，乳酸积累会引起抽筋和肌肉疲劳。在酵母中，无氧呼吸产生乙醇和二氧化碳，这正是酵母用于烘焙和酿酒的原因。
In humans, gas exchange happens in the alveoli in the lungs. Alveoli are adapted in three key ways: there are millions of them so the surface area is huge, their walls are only one cell thick so the diffusion distance is short, and they have a rich blood supply so a steep concentration gradient is maintained.
人体的气体交换发生在肺部的肺泡中。肺泡的适应特征有三点：数量以百万计，因此表面积巨大；壁仅一个细胞厚，扩散距离短；血液供应丰富，因而能维持陡峭的浓度梯度。
Breathing movements bring air in and out. When you inhale, the intercostal muscles and diaphragm contract, the ribcage moves up and out, and the volume of the chest increases so the pressure falls and air rushes in. Exhaling reverses all of these. Smoking damages the alveoli and cilia, which reduces surface area and lets dust and mucus build up in the airways.
呼吸运动让空气进出肺部。吸气时，肋间肌和膈肌收缩，肋骨架向上向外移动，胸腔容积增大，气压下降，空气随之涌入。呼气时上述过程全部相反。吸烟会破坏肺泡和纤毛，从而减小表面积，并使灰尘与黏液在气道中积聚。
9. Working Scientifically: Variables, Data and Graphs | 科学工作法：变量、数据与图表
Every practical you complete in Year 7 is assessed on your working scientifically skills, so learn the language early. A hypothesis is a testable idea; a prediction is what you expect to happen; a conclusion states what your results show and links back to the hypothesis.
七年级完成的每一次实验都会考察你的科学工作技能，因此要尽早掌握这些术语。假设是可用于检验的想法；预测是你预期会发生什么；结论则说明结果显示了什么并回扣假设。
The independent variable is the one you deliberately change. The dependent variable is the one you measure. Control variables are everything you keep the same to make the test fair, such as temperature, volume of water, or the type of plant.
自变量是你有意改变的量。因变量是你测量的量。控制变量是你保持不变的各项条件，以保证实验公平，例如温度、水的体积或植物的种类。
Repeat readings improve reliability. Calculate the mean by adding the results and dividing by the number of readings, ignoring any anomalous result that clearly does not fit the pattern. Report the mean to the same number of decimal places as your data, and always include units such as mm, cm³ or °C.
重复测量可以提高可靠性。计算平均值时，把结果相加再除以测量次数，并剔除明显不符合规律的异常数据。平均值的保留小数位数应与数据一致，并始终写上单位，例如 mm、cm³ 或 °C。
Choose the right graph. Use a bar chart when the independent variable is a category, such as the type of food tested or the species counted. Use a line graph when the independent variable is continuous, such as time or light intensity. Plot the independent variable on the x-axis and the dependent variable on the y-axis, label both axes with units, and draw a smooth line of best fit rather than joining the dots.
选择正确的图表。当自变量是类别时使用柱状图，例如被检测的食物种类或统计的物种。当自变量是连续量时使用折线图，例如时间或光照强度。自变量画在横轴，因变量画在纵轴，两轴都要标注单位，并画出平滑的最佳拟合线，而不是把各点直接连起来。
10. Health and Safety in the Biology Lab | 生物实验室的健康与安全
Before every practical you must read the risk assessment and follow the teacher's instructions. The most basic rules are: wear safety goggles when heating or handling chemicals, tie back long hair, keep your workspace clear, and never taste or smell a substance directly.
每次实验前都必须阅读风险评估并遵从老师指示。最基本的规则是：加热或接触化学品时佩戴护目镜，束起长发，保持工作台整洁，绝不直接品尝或闻取任何物质。
Hazard symbols warn you about the risks. A corrosive substance destroys living tissue, a toxic substance is poisonous if swallowed or inhaled, and a flammable substance catches fire easily, so it must be kept away from a Bunsen burner. Flames need respect: use the blue safety flame for heating, always point the test tube away from yourself and others, and never leave a lit Bunsen unattended.
危险符号用于提示风险。腐蚀性物质会破坏活组织，有毒物质若被吞入或吸入会中毒，易燃物质容易着火，因此必须远离本生灯。对待火焰必须谨慎：加热时使用蓝色安全火焰，试管口始终不要朝向自己或他人，绝不让点燃的本生灯无人看管。
Biological material needs extra care.
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