📚 Year 10 Edexcel Biology: Core Knowledge Review | 10年级 Edexcel 生物：核心知识点梳理
This article provides a comprehensive review of the key topics covered in Year 10 of the Edexcel Biology course. From cell theory to inheritance and homeostasis, we break down the essential concepts you need to master. Each section pairs key explanations in English and Chinese to help bilingual learners consolidate their understanding.
本文全面梳理了Edexcel生物课程10年级的核心知识点，从细胞学说到遗传和稳态，逐一解析必须掌握的重要概念。每个部分都提供中英文对照讲解，帮助双语学习者巩固理解。
1. Cell Theory and Microscopy | 细胞学说与显微镜技术
All living organisms are composed of one or more cells. Cells are the smallest units of life and arise only from pre-existing cells by cell division. This is the fundamental cell theory.
所有生物体都由一个或多个细胞组成。细胞是生命的最小单位，只能通过细胞分裂从已有的细胞产生。这就是细胞学说的基本内容。
ze ÷ Actual size. Total magnification is the eyepiece lens magnification multiplied by the objective lens magnification.
显微镜对于观察细胞至关重要。光学显微镜的放大倍数计算公式为：放大倍数 = 图像大小 ÷ 实际大小。总放大倍数是目镜放大倍数与物镜放大倍数的乘积。
When converting units, remember that 1 mm = 1000 µm and 1 µ lways ensure that the image size and actual size are in the same units before calculating.
进行单位换算时，记住 1 毫米 = 1000 微米，1 微米 = 1000 纳米。计算前务必保证图像大小和实际大小单位一致。
2. Cell Structures: Animal, Plant, and Bacterial Cells | 细胞结构：动物、植物和细菌细胞
Animal cells contain a nucleus, cytoplasm, cell membrane, mitochondria, and ribosomes. Plant cells have all these plus a cellulose cell wall, a large permanent vacuole, and chloroplasts. Bacterial cells are prokaryotic: they lack a nucleus and membrane-bound organelles, and have a circular DNA loop and plasmids.
动物细胞含有细胞核、细胞质、细胞膜、线粒体和核糖体。植物细胞除此之外还有纤维素细胞壁、大型永久液泡和叶绿体。细菌细胞是原核生物：它们没有细胞核和膜结合细胞器，具有环状DNA环和质粒。
The following table compares key structures:
下表比较了关键结构：
| Structure (结构) | Animal Cell (动物细胞) | Plant Cell (植物细胞) | Bacterial Cell (细菌细胞) |
|---|---|---|---|
| Nucleus (细胞核) | Present | Present | Absent |
| Cell wall (细胞壁) | Absent | Present (cellulose) | Present (peptidoglycan) |
| Chloroplasts (叶绿体) | Absent | Present | Absent |
| Mitochondria (线粒体) | Present | Present | Absent |
| Ribosomes (核糖体) | Present | Present | Present (smaller) |
3. Specialised Cells | 特化细胞
Cells differentiate to perform specific functions. In animals, examples include red blood cells (no nucleus, biconcave shape to carry oxygen), sperm cells (tail for swimming, many mitochondria for energy), and nerve cells (long axon for transmitting impulses). In plants, examples are root hair cells (long projection to absorb water and minerals) and xylem vessels (lignified walls, no end walls for water transport).
细胞会分化以执行特定功能。动物中的例子包括红细胞（无细胞核、双凹形状以携带氧气）、精子细胞（有尾部用于游动、大量线粒体提供能量）以及神经细胞（长轴突用于传递冲动）。植物中的例子有根毛细胞（长突起用于吸收水分和矿物质）和木质部导管（木质化细胞壁、无端壁以运输水分）。
Specialisation is the result of gene expression: only certain genes are switched on in each cell type to produce the required proteins and structures.
特化是基因表达的结果：每种细胞类型只开启特定基因，以产生所需的蛋白质和结构。
4. Movement of Substances: Diffusion, Osmosis, and Active Transport | 物质运输：扩散、渗透和主动运输
Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient. It is a passive process requiring no energy. Factors affecting diffusion rate include temperature, concentration gradient, and surface area.
扩散是粒子从高浓度区域到低浓度区域的净移动，沿着浓度梯度进行。这是一个被动过程，不需要能量。影响扩散速率的因素包括温度、浓度梯度和表面积。
Osmosis is the diffusion of water molecules through a partially permeable membrane from a dilute solution to a more concentrated solution. Plant cells become turgid in dilute solutions and plasmolysed in concentrated solutions; animal cells may burst or shrivel.
渗透是水分子通过半透膜从稀溶液向浓溶液的扩散。植物细胞在稀溶液中变得坚挺，在浓溶液中发生质壁分离；动物细胞可能胀破或皱缩。
Active transport moves substances against the concentration gradient, from low to high concentration, using energy from ATP. It requires carrier proteins in the cell membrane, as seen in root hair cells absorbing mineral ions.
主动运输逆浓度梯度将物质从低浓度区域移动到高浓度区域，需要ATP提供的能量。这需要细胞膜上的载体蛋白，例如根毛细胞吸收矿物离子。
5. Enzymes | 酶
Enzymes are biological catalysts that speed up metabolic reactions without being used up. They are globular proteins with an active site that is complementary to a specific substrate. The lock-and-key model describes how the substrate fits into the active site to form an enzyme-substrate complex.
酶是生物催化剂，能加快代谢反应而自身不被消耗。它们是球状蛋白质，具有与特定底物互补的活性位点。锁钥模型描述了底物如何嵌入活性位点形成酶-底物复合物。
Enzyme activity is affected by temperature and pH. As temperature rises, activity increases to an optimum; beyond this, the enzyme denatures and the active site changes shape. Each enzyme also has an optimum pH. Denaturation is often irreversible.
酶活性受温度和pH值影响。温度升高时，活性增加直至最适温度；超过最适温度，酶变性，活性位点形状改变。每种酶也有最适pH值。变性通常是不可逆的。
Enzymes are essential in digestion, respiration, and synthesis of new molecules. For example, amylase breaks down starch into maltose in the mouth and small intestine.
酶在消化、呼吸和新分子合成中至关重要。例如，淀粉酶在口腔和小肠中将淀粉分解为麦芽糖。
6. Human Nutrition: Digestive System | 人体营养：消化系统
The human digestive system breaks down large insoluble molecules into small soluble ones that can be absorbed into the blood. Mechanical digestion occurs in the mouth by chewing and in the stomach by churning. Chemical digestion uses enzymes.
人体消化系统将大的不溶性分子分解为可被血液吸收的小分子可溶物质。机械消化发生在口腔（咀嚼）和胃部（搅拌）。化学消化则需要酶的参与。
Key digestive enzymes include amylase (carbohydrates to sugars), proteases (proteins to amino acids), and lipases (lipids to fatty acids and glycerol). Bile, produced by the liver and stored in the gall bladder, emulsifies fats to increase surface area for lipase action.
关键的消化酶包括淀粉酶（碳水化合物→糖类）、蛋白酶（蛋白质→氨基酸）和脂肪酶（脂质→脂肪酸和甘油）。由肝脏产生、储存在胆囊中的胆汁能乳化脂肪，增加脂肪酶作用的表面积。
Absorption of digested food occurs mainly in the small intestine, where villi provide a large surface area. The products are then transported via the blood to cells for respiration or building new molecules.
消化后的食物主要在小肠吸收，小肠绒毛提供了巨大的表面积。吸收产物随后通过血液运输到细胞，用于呼吸或构建新分子。
7. Gas Exchange: Respiratory System | 气体交换：呼吸系统
The respiratory system provides oxygen to the blood and removes carbon dioxide. Air enters through the nose or mouth, passes the trachea, bronchi, and bronchioles, and reaches the alveoli, where gas exchange occurs.
呼吸系统为血液提供氧气并排出二氧化碳。空气通过鼻或口进入，经过气管、支气管和细支气管，到达气体交换的发生地——肺泡。
Alveoli are adapted for efficient gas exchange: they have thin walls (one cell thick), a large surface area, moist surfaces, and a dense network of capillaries. Oxygen diffuses from the alveoli into the blood, while carbon dioxide diffuses in the opposite direction.
肺泡具有适应高效气体交换的结构：壁极薄（仅一个细胞的厚度），表面积大，表面湿润，且包围着密集的毛细血管网。氧气从肺泡扩散入血液，二氧化碳则反向扩散。
Breathing movements (ventilation) are driven by the diaphragm and intercostal muscles. Inhaling increases the volume of the chest cavity, lowering pressure and drawing air in. Exhaling is the reverse.
呼吸运动（通气）由膈肌和肋间肌驱动。吸气时胸腔容积增大，压力降低，空气被吸入；呼气则相反。
8. Circulatory System | 循环系统
The circulatory system consists of the heart, blood vessels, and blood. The heart is a double pump: the right side pumps deoxygenated blood to the lungs, the left side pumps oxygenated blood to the body. Valves prevent backflow.
循环系统由心脏、血管和血液组成。心脏是一个双泵：右侧将缺氧血泵入肺部，左侧将含氧血泵送到全身。瓣膜可防止血液倒流。
Arteries have thick muscular and elastic walls to withstand high pressure. Veins have thinner walls and contain valves to ensure one-way flow. Capillaries are tiny vessels with walls one cell thick for easy diffusion of substances.
动脉壁厚且富有肌肉和弹性纤维，以承受高压。静脉壁较薄并含有瓣膜，确保单向血流。毛细血管是微小的血管，壁仅一个细胞厚，便于物质扩散。
The blood consists of plasma, red blood cells (carry oxygen using haemoglobin), white blood cells (defend against pathogens), and platelets (clotting). Blood transports nutrients, gases, hormones, and waste products.
血液由血浆、红细胞（用血红蛋白运输氧气）、白细胞（防御病原体）和血小板（凝血）组成。血液运输营养物质、气体、激素和废物。
9. Photosynthesis | 光合作用
Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesise glucose from carbon dioxide and water. It occurs in chloroplasts containing chlorophyll. The overall word equation is:
光合作用是绿色植物和一些其他生物利用阳光，从二氧化碳和水合成葡萄糖的过程。它发生在含有叶绿素的叶绿体中。总的文字方程式为：
carbon dioxide + water → glucose + oxygen
O₂. The glucose produced is used for respiration, converted into starch for storage, or used to make cellulose, proteins, and lipids.
平衡化学方程式需要光能：6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂。所产生的葡萄糖可用于呼吸、转化为淀粉储存，或用于制造纤维素、蛋白质和脂质。
Limiting factors of photosynthesis include light intensity, carbon dioxide concentration, and temperature. At low light, the rate is limited by light; as light increases, other factors become limiting.
光合作用的限制因素包括光照强度、二氧化碳浓度和温度。在低光照下，速率受光照限制；随着光照增加，其他因素成为限制因素。
10. Ecology: Food Chains and Energy Flow | 生态学：食物链与能量流动
A food chain shows the transfer of energy from producers (plants) to primary consumers (herbivores), secondary consumers, and tertiary consumers. Arrows indicate the direction of energy flow.
食物链显示了能量从生产者（植物）到初级消费者（食草动物）、次级消费者和三级消费者的传递。箭头指示能量流动的方向。
Only about 10% of the energy is transferred from one trophic level to the next. Energy is lost through movement, heat, respiration, and undigested materials. This loss limits the length of food chains.
大约只有10%的能量从一个营养级传递到下一个营养级。能量通过运动、热量、呼吸作用和未消化物质而损失。这种损失限制了食物链的长度。
Pyramids of numbers and biomass can represent the relative number or mass of organisms at each level. In most ecosystems, biomass decreases at higher trophic levels.
数量金字塔和生物量金字塔可以表示每个营养级的生物相对数量或质量。在大多数生态系统中，生物量随着营养级升高而减少。
11. Inheritance and Genetics | 遗传与基因
Genes are sections of DNA that code for proteins. They are located on chromosomes in the nucleus. Humans have 46 chromosomes (23 pairs), with one set inherited from each parent.
基因是编码蛋白质的DNA片段，位于细胞核内的染色体上。人类有46条染色体（23对），两套分别遗传自父母。
Alleles are different versions of the same gene. Dominant alleles are expressed even if only one copy is present, while recessive alleles require two copies to be expressed. Homozygous means two identical alleles (e.g. AA or aa); heterozygous means two different alleles (e.g. Aa).
等位基因是同一基因的不同形式。显性等位基因即使只有一个拷贝也能表达，而隐性等位基因需要两个拷贝才能表达。纯合子指两个相同的等位基因（如 AA 或 aa），杂合子指两个不同的等位基因（如 Aa）。
henotypic ratio of 3:1 for the dominant to recessive trait. Punnett squares are used to predict genetic outcomes.
两个杂合亲本（Aa × Aa）的单基因杂交会产生显性性状与隐性性状3:1的表现型比例。庞纳特方格用于预测遗传结果。
12. Homeostasis: Temperature Regulation | 稳态：体温调节
Homeostasis is the maintenance of a constant internal environment. Thermoregulation maintains core body temperature around 37°C, essential for optimal enzyme activity.
稳态是指内环境的恒定维持。体温调节将核心体温维持在37°C左右，这对于最佳酶活性至关重要。
When the body is too hot, responses include vasodilation (widening of skin arterioles), sweating, and hairs lying flat. When too cold, vasoconstriction reduces blood flow near the skin, shivering generates heat, and erector muscles contract to trap insulating air.
当身体过热时，反应包括血管扩张（皮肤小动脉扩张）、出汗和毛发平躺。当身体过冷时，血管收缩减少皮肤附近血流，寒颤产生热量，立毛肌收缩以留存绝缘空气层。
The thermoregulatory centre in the hypothalamus monitors blood temperature and triggers these responses via nerves and hormones. This negative feedback system restores the set point.
下丘脑中的体温调节中枢监测血液温度，并通过神经和激素触发这些反应。这种负反馈系统使体温恢复至设定点。
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