📚 Core Knowledge Review for Year 7 Edexcel Biology | Year 7 Edexcel 生物核心知识点梳理
In Year 7 Edexcel Biology, you will explore the fundamental principles that underpin life on Earth. From the tiny building blocks called cells to the complex systems that keep organisms alive, this review covers the core knowledge you need to master. Understanding these topics will provide a solid foundation for your future studies in biology and help you make sense of the living world around you.
在 Year 7 Edexcel 生物课中，你将探索构成地球生命的基础原理。从称为细胞的微小积木到维持生物体存活的复杂系统，本文梳理了你需要掌握的核心知识点。理解这些主题将为你日后的生物学学习打下坚实基础，并帮助你理解身边的生命世界。
1. Introduction to Cells | 细胞入门
All living organisms are made up of cells. Some organisms, like bacteria and amoeba, consist of a single cell (unicellular), while others, such as humans and trees, are made of many cells (multicellular). Cells are the smallest units of life that can carry out all life processes, including movement, respiration, sensitivity, growth, reproduction, excretion and nutrition. The invention of the microscope allowed scientists to discover and study cells in detail.
所有生物体都由细胞构成。有些生物，如细菌和变形虫，只由一个细胞组成(单细胞生物)，而人类和树木等则由许多细胞构成(多细胞生物)。细胞是能够执行所有生命活动(如运动、呼吸、感应、生长、繁殖、排泄和营养)的最小生命单位。显微镜的发明使科学家能够发现并详细研究细胞。
2. Animal and Plant Cells | 动物与植物细胞
Animal cells have a cell membrane, cytoplasm, nucleus, and mitochondria. The cell membrane controls what enters and leaves the cell. The cytoplasm is a jelly-like substance where chemical reactions occur. The nucleus contains genetic material (DNA) and controls the cell’s activities. Mitochondria are the sites of respiration, releasing energy for the cell. Plant cells have all the parts found in animal cells, plus a cell wall, a large permanent vacuole, and chloroplasts. The cell wall, made of cellulose, provides support and shape. The vacuole contains cell sap and helps keep the cell rigid. Chloroplasts contain chlorophyll and are where photosynthesis takes place.
动物细胞拥有细胞膜、细胞质、细胞核和线粒体。细胞膜控制物质进出细胞。细胞质是果冻状物质，化学反应在此进行。细胞核含有遗传物质(DNA)并控制细胞活动。线粒体是呼吸作用的场所，为细胞释放能量。植物细胞除了具有动物细胞的所有部分，还有细胞壁、一个大液泡和叶绿体。由纤维素组成的细胞壁起支撑和维持形状的作用。液泡含有细胞液，帮助保持细胞坚挺。叶绿体含有叶绿素，是进行光合作用的场所。
| Feature | Animal Cell | Plant Cell |
|---|---|---|
| Cell membrane | Yes | Yes |
| Cytoplasm | Yes | Yes |
| Nucleus | Yes | Yes |
| Mitochondria | Yes | Yes |
| Cell wall | No | Yes (cellulose) |
| Large permanent vacuole | No | Yes |
| Chloroplasts | No | Yes |
Remember that not all plant cells have chloroplasts; for example, root cells are underground and do not photosynthesise.
请记住，并非所有植物细胞都有叶绿体；例如，根细胞生活在地下，不进行光合作用。
3. Specialised Cells | 特化细胞
Multicellular organisms contain cells that are specialised to perform specific functions. A sperm cell has a long tail (flagellum) for swimming and many mitochondria to provide energy. A red blood cell has no nucleus and contains haemoglobin to carry oxygen. A root hair cell in plants has a long thin extension to absorb water and minerals from the soil. A ciliated epithelial cell has tiny hair-like structures called cilia that move mucus and trapped particles in the airways. A palisade cell in leaves contains many chloroplasts for photosynthesis. The structure of each specialised cell is adapted to its job.
多细胞生物的细胞会特化以执行特定功能。精子细胞有一条长长的尾巴(鞭毛)用于游动，以及许多线粒体提供能量。红细胞没有细胞核，含有血红蛋白以携带氧气。植物的根毛细胞具有细长的突起，以从土壤中吸收水分和矿物质。纤毛上皮细胞拥有称为纤毛的微小毛发状结构，可移动呼吸道中的黏液和被捕获的颗粒。叶片中的栅栏细胞含有许多叶绿体，用于光合作用。每种特化细胞的结构都与其功能相适应。
4. Levels of Organisation | 组织层次
In complex organisms, cells are organised into tissues, tissues into organs, and organs into organ systems. A tissue is a group of similar cells working together, such as muscle tissue or xylem tissue in plants. An organ is made of different tissues working together, like the heart or a leaf. An organ system is a group of organs that coordinate to perform a major function, such as the digestive system or the circulatory system. This hierarchy allows organisms to carry out life processes efficiently.
在复杂的生物体中，细胞组织成组织，组织构成器官，器官组成器官系统。组织是一群相似的细胞协同工作，例如肌肉组织或植物中的木质部组织。器官由不同的组织共同构成，如心脏或叶片。器官系统则是一组器官协调执行一个主要功能，如消化系统或循环系统。这种层次结构使生物体能够高效地执行生命活动。
5. The Skeletal System | 骨骼系统
The human skeleton provides support, protects internal organs, allows movement, and produces blood cells in the bone marrow. Bones are connected at joints by ligaments. Important bones include the skull (protecting the brain), the ribcage (protecting the heart and lungs), the spine (backbone), and the long bones of the arms and legs. The skeleton also stores minerals like calcium. The structure of a joint includes cartilage, which cushions the ends of bones, and synovial fluid, which lubricates the joint.
人体骨骼提供支撑、保护内脏器官、允许运动以及在骨髓中制造血细胞。骨头通过韧带在关节处相连。重要的骨骼包括头骨(保护大脑)、肋骨(保护心脏和肺)、脊柱(脊椎)以及手臂和腿的长骨。骨骼还储存钙等矿物质。关节的结构包括软骨，缓冲骨端；以及滑液，润滑关节。
6. Muscles and Movement | 肌肉与运动
Muscles work in antagonistic pairs to move bones at a joint. For example, the biceps and triceps in the upper arm work together. To bend the arm at the elbow, the biceps contracts and pulls on the radius bone, while the triceps relaxes. To straighten the arm, the triceps contracts and the biceps relaxes. Muscles are attached to bones by tough cords called tendons. When a muscle contracts, it becomes shorter and thicker, pulling the bone to cause movement. Muscles need energy from respiration to contract.
肌肉以拮抗对的形式工作，使关节处的骨骼运动。例如，上臂的二头肌和三头肌协同工作。屈肘时，二头肌收缩并拉动桡骨，三头肌放松。伸直手臂时，三头肌收缩，二头肌放松。肌肉通过称为肌腱的坚韧索条附着在骨上。肌肉收缩时变得短而粗，拉动骨骼引起运动。肌肉收缩需要呼吸作用提供的能量。
7. Nutrition and a Balanced Diet | 营养与均衡膳食
A balanced diet provides all the nutrients needed for health in the correct proportions. The main food groups are carbohydrates (for energy), proteins (for growth and repair), lipids or fats (for energy, insulation, and cell membranes), vitamins and minerals (for various bodily functions, e.g., vitamin C for healthy skin, iron for haemoglobin), dietary fibre (to prevent constipation and help digestion), and water (for chemical reactions and transport). Malnutrition can result from eating too much or too little of certain nutrients, leading to conditions such as obesity, starvation, or deficiency diseases like rickets.
均衡膳食按正确比例提供健康所需的所有营养素。主要食物类别有：碳水化合物(提供能量)、蛋白质(用于生长和修复)、脂类或脂肪(提供能量、保温和构建细胞膜)、维生素和矿物质(用于各种身体功能，如维生素C维护皮肤健康，铁用于制造血红蛋白)、膳食纤维(预防便秘并帮助消化)以及水(用于化学反应和运输)。营养不良可能因摄入过多或过少某种营养素而导致，引发肥胖、饥饿或佝偻病等缺乏症。
8. The Digestive System | 消化系统
The digestive system breaks down large, insoluble food molecules into small, soluble ones that can be absorbed into the blood. Food travels through the mouth (where it is chewed and mixed with saliva containing the enzyme amylase to break down starch), the oesophagus (food pipe), the stomach (where acid and enzymes digest proteins), the small intestine (where digestion is completed and nutrients are absorbed into the bloodstream), and the large intestine (where water is absorbed and faeces are formed). The liver and pancreas produce digestive juices that help break down food. The process of absorption relies on the large surface area of the small intestine, which is lined with villi.
消化系统将大的不溶性食物分子分解成小的可溶性分子，以便被血液吸收。食物依次经过口腔(在此咀嚼并与含有淀粉酶的唾液混合，开始分解淀粉)、食道(食管)、胃(胃酸和酶在此消化蛋白质)、小肠(消化在此完成，营养物质被吸收到血液中)和大肠(水分被吸收，形成粪便)。肝脏和胰腺产生消化液帮助分解食物。吸收过程依赖于小肠的大面积表面，小肠内壁布满了绒毛。
9. The Respiratory System and Gas Exchange | 呼吸系统与气体交换
Respiration is the process that releases energy from food; it is not the same as breathing. Breathing moves air in and out of the lungs. Air enters through the nose or mouth, travels down the trachea (windpipe), then through the bronchi and bronchioles, finally reaching tiny air sacs called alveoli. In the alveoli, gas exchange occurs: oxygen diffuses into the blood, and carbon dioxide diffuses from the blood into the lungs to be exhaled. The alveoli are well adapted for this exchange with their large surface area, thin walls, and rich blood supply. The equation for aerobic respiration is:
呼吸作用是释放食物中能量的过程，与呼吸不同。呼吸动作让空气进出肺部。空气通过鼻或口进入，向下经过气管，然后通过支气管和细支气管，最终到达叫做肺泡的微小气囊。在肺泡中发生气体交换：氧气扩散进入血液，二氧化碳从血液扩散进入肺部被呼出。肺泡拥有大面积表面、薄壁和丰富的血液供应，非常适合这种交换。有氧呼吸的方程式为：
Glucose + Oxygen → Carbon Dioxide + Water (+ Energy)
葡萄糖 + 氧气 → 二氧化碳 + 水 (+ 能量)
10. Reproduction in Plants | 植物繁殖
Flowering plants reproduce sexually to produce seeds. The male part of the flower is the stamen, which consists of the anther (producing pollen) and filament. The female part is the carpel, made up of the stigma, style, and ovary (containing ovules). Pollination is the transfer of pollen from the anther to the stigma. This can be carried out by insects, wind, or water. After pollination, a pollen tube grows down to the ovary, and fertilisation occurs when the male nucleus fuses with the female nucleus in the ovule. The fertilised ovule develops into a seed, and the ovary becomes the fruit. Seeds need warmth, water, and oxygen for germination.
开花植物进行有性繁殖以产生种子。花的雄性部分为雄蕊，由花药(产生花粉)和花丝组成。雌性部分为雌蕊，由柱头、花柱和子房(含有胚珠)组成。授粉是花粉从花药传到柱头的过程，可由昆虫、风或水完成。授粉后，花粉管向下长入子房，当雄核与胚珠中的雌核融合时发生受精。受精的胚珠发育成种子，子房发育成果实。种子萌发需要温暖、水分和氧气。
11. Human Reproduction | 人类生殖
Humans reproduce sexually. The male reproductive system includes the testes (where sperm are produced), the sperm ducts, and the penis. The female reproductive system includes the ovaries (where eggs are produced), the oviducts (fallopian tubes), the uterus (womb), and the vagina. During intercourse, sperm are deposited in the vagina and swim to the oviduct. Fertilisation occurs when a sperm cell fuses with an egg cell, forming a zygote. The zygote divides and implants in the lining of the uterus, developing into an embryo. The placenta allows exchange of oxygen, nutrients, and waste between the mother and fetus, without mixing their blood. The amniotic fluid protects the developing fetus.
人类进行有性生殖。男性生殖系统包括睾丸(产生精子)、输精管和阴茎。女性生殖系统包括卵巢(产生卵子)、输卵管(喇叭管)、子宫(孕育处)和阴道。性交时，精子被输送到阴道并游向输卵管。当精子与卵细胞融合形成受精卵时，即为受精。受精卵分裂并植入子宫内膜，发育成胚胎。胎盘让母亲和胎儿之间进行氧气、营养和废物的交换，但两者的血液并不混合。羊水保护发育中的胎儿。
12. Ecosystems and Food Chains | 生态系统与食物链
An ecosystem is a community of living organisms interacting with each other and their non-living environment. Food chains show the transfer of energy from one organism to another. A food chain always starts with a producer (usually a green plant that photosynthesises), followed by a primary consumer (herbivore), then a secondary consumer (carnivore), and possibly a tertiary consumer. Decomposers, such as bacteria and fungi, break down dead material and recycle nutrients back into the soil. Arrows in a food chain point in the direction of energy flow. Populations within an ecosystem depend on each other; changes in one population can affect others, for example through predator-prey relationships.
生态系统是由相互作用的生物群落及其非生物环境构成的统一整体。食物链展示能量从一个生物传递到另一个生物的过程。食物链总是以生产者(通常是能进行光合作用的绿色植物)开始，接着是初级消费者(草食动物)，然后是次级消费者(肉食动物)，可能还有三级消费者。分解者如细菌和真菌分解死亡物质并将养分循环回土壤。食物链中的箭头指向能量流动的方向。生态系统内的种群相互依赖；一个种群的变化可能影响其他种群，例如通过捕食者-猎物关系。
Grass → Rabbit → Fox
草 → 兔子 → 狐狸
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