📚 Year 11 Edexcel Science Core Knowledge Summary | 爱德思科学核心知识点梳理
Year 11 Edexcel Science covers the essential principles of Biology, Chemistry and Physics, forming the foundation for GCSE examinations. A solid grasp of core concepts such as cell biology, atomic structure, forces and energy changes is vital for success. This summary brings together the most important knowledge points from the combined and separate science specifications, presented in a clear bilingual format to aid revision and long-term understanding.
11年级爱德思科学涵盖了生物、化学与物理的核心原理，是GCSE考试的重要基础。牢固掌握细胞生物学、原子结构、力与能量变化等基本概念对于取得好成绩至关重要。本文梳理了综合科学与单科课程中最关键的知识点，以清晰的中英双语形式呈现，帮助复习与深入理解。
1. Cell Biology and Microscopy | 细胞生物学与显微镜技术
All living organisms are composed of cells, which are the basic structural and functional units of life. Prokaryotic cells lack a nucleus, while eukaryotic cells have a membrane-bound nucleus containing genetic material.
所有生物都由细胞构成，细胞是生命的基本结构和功能单位。原核细胞没有细胞核，而真核细胞具有由膜包裹的细胞核，内含遗传物质。
Animal cells contain a nucleus, cytoplasm, cell membrane, mitochondria and ribosomes. Plant cells additionally have a rigid cell wall, a large permanent vacuole and chloroplasts for photosynthesis.
动物细胞包含细胞核、细胞质、细胞膜、线粒体和核糖体。植物细胞还具有坚硬的细胞壁、一个大的中央液泡以及进行光合作用的叶绿体。
Microscopy techniques allow us to observe cells. The magnification formula is: magnification = size of image / actual size of object. Electron microscopes have greater resolution and magnification than light microscopes, revealing subcellular structures.
显微镜技术使我们能够观察细胞。放大倍数计算公式为：放大倍数 = 图像大小 / 物体实际大小。电子显微镜比光学显微镜拥有更高的分辨率和放大倍数，可呈现亚细胞结构。
Enzyme activity is affected by temperature and pH. Each enzyme has an optimum condition where the rate of reaction is highest; extreme conditions can denature the enzyme, changing the shape of its active site.
酶的活性受温度和pH值影响。每种酶都有一个最适条件，此时反应速率最高；极端条件会使酶变性，改变其活性位点的形状。
2. Enzymes and Digestion | 酶与消化
Enzymes are biological catalysts that speed up chemical reactions in living organisms without being used up. The lock-and-key model explains how a substrate fits into the enzyme’s active site to form an enzyme-substrate complex.
酶是生物催化剂，能加速生物体内的化学反应而自身不被消耗。锁钥模型解释了底物如何嵌入酶的活性位点，形成酶-底物复合物。
In the digestive system, large insoluble molecules are broken down into smaller soluble ones. Carbohydrases like amylase break down starch into sugars; proteases break down proteins into amino acids; lipases break down lipids into fatty acids and glycerol.
在消化系统中，大分子不溶性物质被分解为可溶的小分子。淀粉酶等糖酶将淀粉分解成糖类；蛋白酶将蛋白质分解为氨基酸；脂肪酶将脂质分解为脂肪酸和甘油。
Bile is produced in the liver and stored in the gall bladder. It emulsifies fats, increasing the surface area for lipase action, and also neutralises stomach acid to provide an alkaline pH for enzymes in the small intestine.
胆汁在肝脏中产生并储存在胆囊中。它将脂肪乳化，增大脂肪酶作用的表面积，同时中和胃酸，为小肠中的酶提供碱性pH环境。
3. The Circulatory System and Health | 循环系统与健康
The heart is a muscular organ that pumps blood around the body. The right side pumps deoxygenated blood to the lungs, while the left side pumps oxygenated blood to the rest of the body. Valves prevent backflow.
心脏是一个将血液泵送至全身的肌肉器官。右侧将缺氧血泵到肺部，左侧将富氧血泵到身体其他部位。瓣膜能防止血液倒流。
Arteries carry blood away from the heart under high pressure; veins return blood at low pressure and contain valves; capillaries are thin-walled to allow exchange of substances with tissues. Red blood cells transport oxygen, white blood cells fight infection, and platelets help clotting.
动脉在高压下将血液从心脏送出；静脉在低压下将血液送回并含有瓣膜；毛细血管壁薄，便于与组织进行物质交换。红细胞运输氧气，白细胞抵抗感染，血小板帮助凝血。
Lifestyle factors such as diet, exercise and smoking affect the risk of cardiovascular disease. A high-fat diet can lead to fatty deposits in arteries, narrowing the lumen and increasing blood pressure. Regular exercise helps maintain a healthy heart.
饮食、运动和吸烟等生活方式因素会影响心血管疾病的风险。高脂饮食可能导致动脉内脂肪沉积，使管腔变窄并升高血压。定期锻炼有助于保持心脏健康。
4. DNA, Inheritance and Evolution | DNA、遗传与进化
DNA is a double-helix polymer made of nucleotides, each containing a sugar, a phosphate group and a base (A, T, C, G). Complementary base pairing (A-T, C-G) holds the two strands together. A gene is a section of DNA that codes for a particular protein.
DNA是一种双螺旋结构的聚合物，由核苷酸组成，每个核苷酸包含一个糖、一个磷酸基团和一个碱基（A、T、C、G）。互补碱基配对（A-T、C-G）使两条链连接在一起。基因是编码特定蛋白质的DNA片段。
Inheritance follows patterns described by Punnett squares. Alleles can be dominant or recessive. Homozygous individuals carry two identical alleles, while heterozygous individuals carry two different alleles. Some characteristics are determined by multiple genes.
遗传遵循由庞纳特方格描述的模式。等位基因有显性和隐性之分。纯合个体携带两个相同的等位基因，杂合个体携带两个不同的等位基因。某些特征由多基因共同决定。
Evolution by natural selection acts on variation within a population. Individuals with advantageous traits are more likely to survive and reproduce, passing on their alleles. Over time, this leads to changes in the inherited characteristics of a population.
自然选择作用于种群内的变异。具有有利性状的个体更可能生存和繁殖，将其等位基因传递下去。随着时间的推移，这会导致种群的遗传特征发生改变。
5. Atomic Structure and the Periodic Table | 原子结构与元素周期表
All substances are made of atoms. An atom consists of a central nucleus containing protons and neutrons, surrounded by electrons arranged in shells. Protons have a relative mass of 1 and a positive charge, neutrons are neutral with mass 1, and electrons have negligible mass and a negative charge.
所有物质都由原子构成。原子由一个包含质子和中子的原子核以及核外分层排布的电子组成。质子相对质量为1且带正电荷，中子为电中性质量1，电子质量极小且带负电荷。
Atomic number is the number of protons, which determines the element. Mass number is the sum of protons and neutrons. Isotopes are atoms of the same element with different numbers of neutrons. Electron configuration follows the pattern 2,8,8 for the first 20 elements.
原子序数等于质子数，决定了元素的种类。质量数是质子数与中子数之和。同位素是同种元素的中子数不同的原子。前20号元素的电子排布遵循2、8、8的规律。
In the modern periodic table, elements are arranged in order of increasing atomic number. Groups contain elements with similar chemical properties because they have the same number of outer electrons. Periods correspond to the number of occupied electron shells.
现代元素周期表中，元素按原子序数递增排列。同一族的元素具有相似的化学性质，因为它们的最外层电子数相同。周期数对应已占据的电子层数。
6. Chemical Bonding and Structure | 化学键与结构
Ionic bonding occurs between metals and non-metals. Metals lose electrons to become positive ions, while non-metals gain electrons to become negative ions. The electrostatic attraction between oppositely charged ions forms a giant ionic lattice. Ionic compounds have high melting points and conduct electricity when molten or dissolved.
离子键形成于金属与非金属之间。金属失去电子成为阳离子，非金属得到电子成为阴离子。带相反电荷的离子之间的静电引力形成巨大的离子晶格。离子化合物熔点高，在熔融或溶解时能够导电。
Covalent bonding happens when non-metal atoms share pairs of electrons. Simple covalent molecules like water and carbon dioxide have low melting points and do not conduct electricity. Giant covalent structures, such as diamond and graphite, have very high melting points; graphite contains delocalised electrons and can conduct electricity.
共价键由非金属原子通过共用电子对形成。像水和二氧化碳这样的简单共价分子熔点低且不导电。金刚石和石墨等巨型共价结构熔点极高；石墨中含有离域电子，能够导电。
Metallic bonding consists of positive metal ions arranged in a regular lattice, surrounded by a ‘sea’ of delocalised electrons. This structure allows metals to conduct heat and electricity and to be malleable and ductile.
金属键由规则排列的金属阳离子和周围离域电子的“海洋”构成。这种结构使金属能够导热、导电，并具有延展性和韧性。
7. Quantitative Chemistry and Moles | 定量化学与摩尔
The relative atomic mass (Ar) is the average mass of an atom of an element compared to 1/12 of the mass of a carbon-12 atom. The relative formula mass (Mr) is the sum of the relative atomic masses in a formula unit.
相对原子质量（Ar）是一个元素原子的平均质量与一个碳-12原子质量的1/12的比值。相对式量（Mr）是化学式单元中各原子的相对原子质量之和。
A mole of a substance contains 6.02 × 10²³ particles (Avogadro constant). The mass of one mole of a substance in grams is equal to its relative formula mass. Calculations involve: moles = mass (g) / Mr.
一摩尔物质含有6.02 × 10²³个微粒（阿伏伽德罗常数）。一摩尔物质的质量（克）等于其相对式量。相关计算为：摩尔数 = 质量 (g) / Mr。
In a chemical reaction, mass is conserved. Balanced equations allow us to calculate the masses of reactants and products. Limiting reactants determine the amount of product formed. Percentage yield compares actual and theoretical yields.
在化学反应中，质量是守恒的。配平的化学方程式使我们能够计算反应物和产物的质量。限制反应物决定了产物的生成量。产率百分比比较了实际产量与理论产量。
8. Rates of Reaction and Energy Changes | 反应速率与能量变化
The rate of a chemical reaction can be measured by monitoring the rate at which reactants are used up or products are formed. Common methods include measuring gas volume, mass loss, or colour change over time.
化学反应的速率可以通过监测反应物消耗或产物生成的快慢来测定。常用方法包括测量气体体积、质量损失或随时间变化的颜色改变。
Factors that increase collision frequency or the proportion of particles with energy greater than activation energy will increase the rate. These are: temperature, concentration (or pressure for gases), surface area of solids, and the use of a catalyst.
任何增加碰撞频率或提高能量超过活化能的微粒比例的因素都会加快反应速率。这些因素包括：温度、浓度（或气体压强）、固体表面积以及使用催化剂。
Exothermic reactions transfer thermal energy to the surroundings, shown by a rise in temperature (e.g., combustion, neutralisation). Endothermic reactions take in energy from the surroundings, shown by a fall in temperature (e.g., photosynthesis, thermal decomposition). Energy profile diagrams show activation energy and overall ΔH.
放热反应向环境释放热能，表现为温度升高（如燃烧、中和反应）。吸热反应从环境中吸收能量，表现为温度降低（如光合作用、热分解）。能级图展示了活化能和整体ΔH。
9. Motion and Forces | 运动与力
Speed is a scalar quantity while velocity is a vector, having both magnitude and direction. Acceleration is the rate of change of velocity. Motion can be represented on distance-time and velocity-time graphs; the gradient of a distance-time graph gives the speed.
速率是一个标量，而速度是既有大小又有方向的矢量。加速度是速度的变化率。运动可以用距离-时间图和速度-时间图表示；距离-时间图的斜率代表速率。
The equations of uniformly accelerated motion include: v = u + at and v² = u² + 2as, where u is initial velocity, v is final velocity, a is acceleration, t is time, and s is displacement.
匀加速运动的方程包括：v = u + at 和 v² = u² + 2as，其中u是初速度，v是末速度，a是加速度，t是时间，s是位移。
Newton’s laws of motion are fundamental: First law – an object remains at rest or constant velocity unless acted on by a resultant force. Second law: F = ma. Third law – every action has an equal and opposite reaction. Stopping distance is the sum of thinking distance and braking distance, affected by speed, alertness and road conditions.
牛顿运动定律是基础：第一定律——物体在不受合力作用时保持静止或匀速直线运动。第二定律：F = ma。第三定律——每一个作用力都有一个大小相等、方向相反的反作用力。停车距离是反应距离与制动距离之和，受车速、警觉度及路况影响。
10. Waves and the Electromagnetic Spectrum | 波与电磁波谱
Waves transfer energy without transferring matter. In transverse waves, oscillations are perpendicular to the direction of energy transfer (e.g., light, ripples on water). In longitudinal waves, oscillations are parallel to energy transfer (e.g., sound).
波传递能量而不传递物质。在横波中，振动方向与能量传递方向垂直（如光、水波）。在纵波中，振动方向与能量传递方向平行（如声波）。
Key wave quantities include amplitude, wavelength, frequency and wave speed. The wave equation is: v = f λ, where v is speed (m/s), f is frequency (Hz), and λ is wavelength (m).
波的关键物理量包括振幅、波长、频率和波速。波动方程为：v = f λ，其中v为波速（米/秒），f为频率（赫兹），λ为波长（米）。
The electromagnetic spectrum is a continuous range of transverse waves that travel at the same speed in a vacuum (3.0 × 10⁸ m/s). The spectrum, in order of increasing frequency, is: radio, microwave, infrared, visible, ultraviolet, X-ray, gamma. Different parts of the spectrum have different uses and dangers.
电磁波谱是一系列在真空中传播速度相同（3.0 × 10⁸ 米/秒）的横波。按频率递增顺序为：无线电波、微波、红外线、可见光、紫外线、X射线、伽马射线。波谱不同部分各有用处与危害。
11. Electricity and Circuits | 电流与电路
Electric current is the rate of flow of charge. In a metallic conductor, current is carried by delocalised electrons. Charge (Q), current (I) and time (t) are related by: Q = I t. Potential difference (V) is the energy transferred per unit charge.
电流是电荷流动的速率。在金属导体中，电流由离域电子携带。电荷量（Q）、电流（I）和时间（t）的关系为：Q = I t。电势差（V）是每单位电荷转移的能量。
Ohm’s law states that the current through a resistor is directly proportional to the potential difference, provided temperature remains constant: V = I R. Resistance is measured in ohms (Ω). In series circuits, current is the same everywhere and p.d. is shared; in parallel circuits, p.d. is the same across branches and current is divided.
欧姆定律指出，在温度保持不变的条件下，通过电阻器的电流与两端电势差成正比：V = I R。电阻的单位是欧姆（Ω）。在串联电路中，各处电流相同而电压被分配；在并联电路中，各支路电压相同而电流分流。
Components such as diodes and thermistors have non-linear characteristics. Mains electricity is an a.c. supply at 50 Hz with a live wire at 230 V. Electrical safety features include fuses, circuit breakers and earthing.
二极管和热敏电阻等元件具有非线性特性。市电是频率50 Hz的交流电，火线电压230 V。电气安全装置包括保险丝、断路器和接地线。
12. Radioactivity and Nuclear Physics | 放射性与核物理
Some atomic nuclei are unstable and emit ionising radiation to become more stable. The three main types are alpha particles (helium nuclei), beta particles (fast electrons), and gamma rays (electromagnetic waves). Each is different in penetrating power and ionising ability.
某些原子核不稳定，会发出电离辐射以变得更稳定。三种主要辐射是α粒子（氦核）、β粒子（高速电子）和γ射线（电磁波）。它们的穿透能力和电离能力各不相同。
Nuclear equations represent radioactive decay. In alpha decay, the atomic number decreases by 2 and mass number by 4. In beta decay, a neutron turns into a proton plus an electron; the atomic number increases by 1 while mass number stays the same. Gamma emission often accompanies these decays.
核方程表示放射性衰变。在α衰变中，原子序数减2，质量数减4。在β衰变中，一个中子转变为一个质子加一个电子；原子序数加1而质量数不变。γ射线常伴随这些衰变放出。
Radioactive decay is random, but the rate of decay is described by half-life – the time taken for half the unstable nuclei in a sample to decay. Ionising radiation is used in medicine for imaging and therapy, as well as in industry for thickness monitoring, but must be handled safely to minimise irradiation and contamination.
放射性衰变是随机的，但衰变速率用半衰期描述——样品中一半不稳定原子核发生衰变所需的时间。电离辐射在医学中用于成像和治疗，在工业中用于厚度监测，但必须安全操作以尽量减少照射和污染。
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