Summer Bridging Course: Year 7 CAIE Biology | 暑期预习与衔接课程：七年级CAIE生物

📚 Summer Bridging Course: Year 7 CAIE Biology | 暑期预习与衔接课程：七年级CAIE生物

Moving from primary science into Year 7 Biology is an exciting step. This summer bridging guide will help you explore the key topics you are going to meet in the CAIE Lower Secondary Biology course, build your confidence with scientific vocabulary, and develop the skills needed to think and work like a biologist. Whether you are looking at pond water under a magnifying glass or wondering why leaves change colour, biology begins with curiosity — and this article will show you how to turn that curiosity into lasting knowledge.

从小学科学迈向七年级生物是非常激动人心的一步。这份暑期衔接指南将帮助你提前了解 CAIE 初中生物课程的核心主题，建立对科学词汇的信心，并培养像生物学家一样思考和动手的能力。无论你是在用放大镜观察池塘水，还是好奇为什么叶子会变色，生物学都始于好奇心——而本文会教你如何把这份好奇转化为持久的知识。

1. Welcome to Biology | 欢迎进入生物学

Biology is the natural science that studies life and all living organisms, from the tiniest bacteria to giant blue whales. In Year 7, you will begin to ask questions such as ‘What does it mean to be alive?’ and ‘How do living things interact with each other and their environment?’. You will discover that biology is not just about memorising facts — it is about observing the world, designing experiments and explaining how living systems work.

生物学是研究生命以及所有生物体的自然科学，从最微小的细菌到巨大的蓝鲸都属于它的范畴。在七年级，你会开始提出诸如“活着意味着什么？”以及“生物体之间、生物与环境之间如何相互作用？”等问题。你将发现，生物学不仅仅是记忆事实——它还关乎观察世界、设计实验以及解释生命系统是如何运作的。

Your learning will connect directly with everyday life: why you breathe faster when you exercise, how plants produce the oxygen we need, and what makes a balanced diet. By understanding the basic principles early, you will build a solid foundation for later topics such as genetics, ecology and human physiology.

你的学习将和日常生活直接联系起来：为什么运动时呼吸会加快，植物如何制造我们所需的氧气，以及什么才是均衡的膳食。尽早理解这些基本原理，就能为日后的遗传学、生态学和人体生理学等课题打下扎实的基础。

2. The Seven Life Processes | 七大生命过程

To decide whether something is alive, biologists use a list of seven life processes often remembered by the acronym MRS GREN. Every living organism carries out these 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.

要判断某个东西是否具有生命，生物学家通常会使用七个生命过程，常被缩略为 MRS GREN 方便记忆。每一个生物体都要进行这些过程：运动、呼吸、感应、生长、繁殖、排泄和营养。一辆汽车可能会运动并消耗燃料，但它无法生长或繁殖，因此它不是生物。

Let us look at each one briefly. Movement includes the ability of whole organisms to change position, but also movement inside cells. Respiration is the chemical release of energy from food — do not confuse it with breathing! Sensitivity means detecting and responding to changes in the surroundings. Growth happens when cells increase in size or number. Reproduction creates new individuals and ensures a species does not die out. Excretion removes waste products of metabolism, and nutrition means taking in materials for energy, growth and repair.

我们来逐一简要介绍。运动既包括整个生物体改变位置的能力，也包括细胞内部的运动。呼吸作用是从食物中化学释放能量的过程——不要把它和“呼吸（breathing）”混淆！感应是指察觉周围环境中的变化并作出反应。生长发生在细胞体积增大或数量增多时。繁殖产生新的个体，确保物种不会灭绝。排泄是清除新陈代谢产生的废物，而营养则是指摄入用于提供能量、促进生长和修复的物质。

3. Introduction to Cells | 细胞入门

All living things are made of cells. Some organisms, like bacteria and amoeba, consist of only one cell (unicellular), while humans have trillions. The cell is the smallest unit that can carry out all seven life processes. In Year 7, you will use a light microscope to look at plant and animal cells and learn to draw simple diagrams.

所有生物都由细胞组成。有些生物，比如细菌和变形虫，仅由一个细胞构成（单细胞生物），而人类则拥有数万亿个细胞。细胞是能够独立完成全部七大生命过程的最小单位。在七年级，你将学习使用光学显微镜来观察植物和动物细胞，并学会绘制简单的示意图。

Typical structures you will meet include the nucleus, which controls the cell’s activities and contains genetic material; the cytoplasm, a jelly-like substance where most chemical reactions occur; the cell membrane, which controls what enters and leaves the cell; mitochondria, where respiration takes place; and in plant cells, a rigid cell wall, a large permanent vacuole and chloroplasts for photosynthesis. The table below compares key parts.

你将遇见的典型结构包括：细胞核，它控制着细胞的活动并含有遗传物质；细胞质，一种果冻状物质，大部分化学反应在此进行；细胞膜，控制物质进出细胞；线粒体，呼吸作用发生的场所；而在植物细胞中，还有坚硬的细胞壁、一个中央大液泡以及用于进行光合作用的叶绿体。下表对关键部分进行了比较。

Cell Structure	Plant Cell	Animal Cell
Cell wall	Present (made of cellulose)	Absent
Chloroplasts	Present in green parts	Absent
Large vacuole	Usually one large central vacuole	Small or absent
Nucleus, cytoplasm, membrane, mitochondria	Present	Present

Understanding these differences helps explain why plants can make their own food while animals must consume other organisms. As you become familiar with cell diagrams, always label the structures clearly and use a sharp pencil for your scientific drawings.

理解这些差异有助于解释为什么植物能自己制造食物，而动物必须摄取其他生物。当你开始熟悉细胞图示后，要始终清晰地标记各个结构，并使用削尖的铅笔完成科学绘图。

4. Plant vs. Animal Cells | 植物细胞与动物细胞的比较

When you put a plant cell and an animal cell side by side, three extra parts stand out in the plant cell: the cell wall, chloroplasts and the permanent vacuole. The cell wall, made of cellulose, gives the plant strength and shape — this is why a celery stalk stays crunchy. Chloroplasts contain chlorophyll, a green pigment that captures light energy for photosynthesis. The large vacuole holds cell sap and helps maintain turgor pressure, keeping the plant upright.

当你把植物细胞和动物细胞并排比较时，植物细胞中有三个额外的结构会十分突出：细胞壁、叶绿体和中央大液泡。由纤维素构成的细胞壁为植物提供支撑和固定形状——这就是芹菜茎能保持脆嫩的原因。叶绿体中含有叶绿素，这是一种能捕获光能以进行光合作用的绿色色素。大液泡中储存着细胞液，并有助于维持膨压，使植物保持直立。

Animal cells lack these structures and instead have a more flexible outer membrane that allows different shapes, such as the long extensions of nerve cells. Both cell types, however, contain mitochondria where respiration releases energy from glucose. A useful way to remember the energy equation is:

动物细胞没有这些结构，取而代之的是一个更柔韧的外层细胞膜，使细胞能够呈现不同的形态，例如神经细胞的长长突起。不过，两种细胞类型都含有线粒体，呼吸作用在此处将葡萄糖中的能量释放出来。一个有助于记忆能量转换方程的方法是：

Glucose + Oxygen → Carbon dioxide + Water (+ energy)

葡萄糖 + 氧气 → 二氧化碳 + 水（+ 能量）

This reaction happens in nearly all living cells and is why organisms need a constant supply of nutrients and oxygen.

这个反应几乎发生在所有活细胞中，这也说明了为什么生物体需要持续不断地获取营养和氧气。

5. Classification: Grouping Living Things | 分类：将生物分组

Biologists sort the enormous variety of life into groups to make it easier to study. The system you will meet in Year 7 is based on observable characteristics and places organisms into the five kingdoms: Animals, Plants, Fungi, Protists and Prokaryotes (bacteria). Within each kingdom, organisms are further divided — for example, the animal kingdom is split into vertebrates and invertebrates.

生物学家将种类繁多的生物分成不同类群，以便于研究。你将在七年级接触到的分类系统基于可观察的特征，把生物归入五个界：动物界、植物界、真菌界、原生生物界和原核生物界（细菌）。每个界内的生物还会被进一步划分——例如，动物界分为脊椎动物和无脊椎动物。

Vertebrates are animals with a backbone and are grouped into five classes: fish, amphibians, reptiles, birds and mammals. Each class has distinctive features. Mammals, for example, have hair or fur, give birth to live young (with a few exceptions) and feed their young with milk. Birds have feathers, beaks and lay hard-shelled eggs. Learning to use a dichotomous key — a tool that presents paired statements — will be an essential practical skill for identifying organisms.

脊椎动物是拥有脊柱的动物，可分成五类：鱼类、两栖类、爬行类、鸟类和哺乳类。每一类都具有独特的特征。例如，哺乳类有毛发，通常直接生下幼崽（少数例外），并用乳汁喂养后代。鸟类有羽毛、喙，并产下硬壳蛋。学会使用二分叉检索表——一种提供成对陈述的识别工具——将是鉴定生物的一项关键实验技能。

6. Plants: Making Their Own Food | 植物：自给自足的食物工厂

One of the most important chemical processes on Earth is photosynthesis. Green plants use sunlight to convert carbon dioxide and water into glucose and oxygen. The overall word equation is:

地球上最重要的化学过程之一就是光合作用。绿色植物利用阳光，将二氧化碳和水转化为葡萄糖和氧气。总文字方程式为：

Carbon dioxide + Water → Glucose + Oxygen

二氧化碳 + 水 → 葡萄糖 + 氧气

Remember that chlorophyll and light energy are required for this reaction to take place, but they are not used up — they act as catalysts. The glucose produced can be used immediately for respiration, stored as starch or converted into other substances such as cellulose for cell walls and proteins for growth.

请记住，这个反应需要叶绿素和光能才能发生，但它们并不会被消耗——它们扮演着催化剂的角色。产生的葡萄糖可以立刻用于呼吸作用，也可以以淀粉的形式储存起来，或者转化成其他物质，比如用于构建细胞壁的纤维素，以及用于生长的蛋白质。

In addition, plants need mineral ions from the soil. Nitrates are needed for making amino acids and proteins; magnesium is essential for chlorophyll production. When a plant shows yellowing leaves, it may be deficient in magnesium. Simple experiments with potted seedlings can demonstrate the importance of these minerals.

此外，植物还需要从土壤中吸收矿物质离子。硝酸盐用于制造氨基酸和蛋白质；镁对于叶绿素的合成至关重要。当植物的叶片变黄时，有可能是缺乏镁元素。利用盆栽幼苗进行简单的实验，就可以证明这些矿物质的重要性。

7. Your Body’s Organ Systems | 人体的器官系统

Cells of the same type work together to form tissues; tissues form organs, and organs are arranged into organ systems. In Year 7, you will be introduced to several key human body systems: the digestive system, the respiratory system, the circulatory system and the skeletal system. Each system has a specific job, but they all depend on each other to keep the body functioning.

同类型的细胞共同构成组织；组织构成器官，而器官又进一步组合成器官系统。在七年级，你将初步了解人体的几个关键系统：消化系统、呼吸系统、循环系统和骨骼系统。每个系统都有自己特定的功能，但它们相互依赖，共同维持身体的正常运转。

The digestive system breaks down large, insoluble food molecules into small, soluble ones that can be absorbed into the blood. The main organs include the mouth, oesophagus, stomach, small intestine and large intestine. The respiratory system brings oxygen into the body and removes carbon dioxide. Gas exchange happens in the alveoli, tiny air sacs in the lungs. The circulatory system then transports oxygen, digested food and waste products around the body, with the heart acting as a powerful pump.

消化系统将大块、不可溶的食物分子分解为可以吸收到血液中的小分子可溶性物质。主要器官包括口腔、食道、胃、小肠和大肠。呼吸系统将氧气带入体内并排出二氧化碳，气体交换在肺泡（肺部的微小气囊）中进行。之后，循环系统将氧气、已消化的食物以及代谢废物运送到全身各处，而心脏则充当强有力的泵。

When you study these systems, a common misconception is that the stomach does all the digesting. In reality, most chemical digestion and absorption happens in the small intestine. Linking structure to function will be a recurring theme — for example, the small intestine has millions of tiny finger-like projections called villi that increase its surface area for absorption.

在学习这些系统时，一个常见的误解是认为胃负责全部的消化过程。实际上，大多数化学消化和营养吸收在小肠中完成。将结构与功能联系起来将是一个反复出现的学习主题——例如，小肠内壁上有数百万个微小的指状突起，称为绒毛，它们大大增加了吸收营养的表面积。

8. Food Chains and Webs | 食物链和食物网

Ecology in Year 7 begins with simple feeding relationships. A food chain shows the flow of energy from a producer (usually a green plant) to a series of consumers. For instance: Grass → Rabbit → Fox. The arrows represent the direction of energy transfer — ‘is eaten by’. You will learn that the first consumer is called a primary consumer, the next a secondary consumer, and so on.

七年级的生态学从简单的取食关系开始。一条食物链展示了能量从生产者（通常是绿色植物）流向一系列消费者的过程。例如：青草 → 兔子 → 狐狸。箭头代表能量传递的方向——即“被……吃掉”。你将学习到，第一个消费者被称为初级消费者，下一个则是次级消费者，依此类推。

In reality, feeding relationships are more complex, forming a food web. A single organism may eat several types of food and be eaten by several different predators. Decomposers, such as bacteria and fungi, are not always shown in chains but play a vital role in breaking down dead material and returning nutrients to the soil.

在现实中，取食关系更为复杂，它们交织在一起形成了食物网。一种生物可能会吃多种食物，并可能被多种不同的捕食者吃掉。分解者，如细菌和真菌，虽然不一定总是出现在食物链图示中，但它们却扮演着至关重要的角色：分解死去的有机体，并将养分归还给土壤。

You will also meet terms like herbivore, carnivore and omnivore. To bring the topic to life, try building a food web of your local garden or park. List the plants you see, the insects on them, the birds you spot and any larger animals. Drawing a web around your list shows just how interconnected nature really is.

你还会接触到诸如植食动物、肉食动物和杂食动物等术语。为了让这个主题变得生动，不妨尝试构画一个你身边花园或公园里的食物网。列出你看到的植物、植物上的昆虫、你观察到的鸟类以及任何更大的动物。围绕着这个清单画出网状关系，你便会发现大自然中万物相互关联的程度有多深。

9. Scientific Inquiry and Practical Work | 科学探究与实验工作

Biology is a practical subject. In Year 7, you will learn how to plan investigations, identify independent, dependent and control variables, record results in tables and draw graphs. Writing a clear method using bossy verbs (e.g., ‘Measure 10 cm³ of water’, ‘Record the temperature every minute’) will be a frequent task. Safety is paramount — always listen to your teacher’s instructions and tie back long hair, especially when using a Bunsen burner.

生物学是一门实践性学科。在七年级，你将学习如何设计探究实验，识别自变量、因变量和控制变量，将结果记录于表格中并绘制图表。使用指令性动词来书写清晰的实验步骤（例如“量取 10 cm³ 的水”，“每分钟记录一次温度”）将是一项经常性的任务。安全永远是第一位的——你必须始终仔细听取老师的指导，并在使用本生灯时扎好长发。

Even before you enter the laboratory, you can practise key skills at home. Try the classic celery-in-dyed-water experiment to see how coloured water travels up the xylem vessels. Or place a few drops of iodine on a slice of potato to test for starch. Make predictions, note what you observe and try to explain your results using scientific language you have learned.

甚至在进入实验室之前，你就可以在家练习关键技能。不妨尝试经典的芹菜染色实验，观察有颜色的水是如何沿着木质部导管向上输送的。或者在土豆片上滴几滴碘液来检测淀粉。做出预测，记录所观察到的现象，并尝试用你学到的科学语言来解释结果。

Remember, a valid investigation must be fair. That means changing only one variable at a time and keeping all others the same. This idea is the backbone of scientific thinking and will be used throughout your secondary science years.

请记住，一项有效的探究必须是公平的。这意味着每次只能改变一个变量，而保持其他所有变量不变。这一理念是科学思维的支柱，并将贯穿你的整个中学科学学习生涯。

10. Tips for a Successful Transition | 顺利衔接的小贴士

Moving up to Year 7 brings more subject specialist lessons and higher expectations for independent work. Here are some tips to help you feel ready by the end of the summer:

升入七年级意味着更多学科专业课程以及更高的自主学习要求。以下是一些小贴士，帮助你在暑假结束时做好充分准备：

Read a good children’s science book or watch reliable nature documentaries. David Attenborough’s series remain outstanding sources of inspiration.

阅读一本优秀的少儿科学读物或观看可靠的纪录片。大卫·爱登堡的系列作品始终是极佳的灵感来源。
Start a science vocabulary diary. Each time you meet a new word like ‘photosynthesis’ or ‘vertebrate’, write it down with a simple definition and a picture.

准备一本科学词汇日记。每当你遇到像“photosynthesis”或“vertebrate”这样的新词，就把它记下来，附上简单的定义并配一幅图。
Practise drawing and labelling from real photographs. Sketch a flower, a leaf or an insect and label the parts you can identify.

照着实物照片练习绘图和标注。画一朵花、一片叶子或一只昆虫，并标注你能辨认的部位。
Ask ‘why’ questions. Biology thrives on curiosity. Why is the grass wet in the morning? Why does bread go mouldy? Explore answers with an adult or by using a reliable online resource.

多问“为什么”。生物学因好奇心而蓬勃发展。为什么清晨的草是湿的？为什么面包会发霉？与大人一起探讨，或者借助可靠的网络资源去寻找答案。

Lastly, do not worry if you do not understand everything straight away. Year 7 is a journey, and every biologist started exactly where you are. Keep your curiosity alive, and you will soon find yourself thinking like a scientist.

最后，如果你没有马上理解所有内容，也不必担心。七年级本身就是一个学习旅程，每一位生物学家都是从你如今的位置起步的。保持你的好奇心，很快你就会发现自己正像科学家一样思考。

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Summer Bridging Course: Year 7 CAIE Biology | 暑期预习与衔接课程：七年级CAIE生物