📚 Core Knowledge Review for Year 11 WJEC Science | Year 11 WJEC 科学：核心知识点梳理
As Year 11 students prepare for their WJEC Science examinations, a solid grasp of the core concepts across Biology, Chemistry and Physics is essential. This article brings together the most important knowledge points in a clear and structured way, helping you to review effectively and build confidence for the final assessments.
对于正在备战 WJEC 科学考试的 Year 11 学生来说，牢固掌握生物、化学和物理的核心概念至关重要。本文以清晰、有条理的方式汇聚了最重要的知识点，帮助你高效复习，为最终评估树立信心。
1. Cell Structure and Transport | 细胞结构与物质运输
All living organisms are composed of cells, which can be prokaryotic (without a nucleus) or eukaryotic (with a nucleus). Plant and animal cells are eukaryotic; bacteria are prokaryotic. Key organelles include the nucleus, cytoplasm, cell membrane, mitochondria and ribosomes in animal cells, plus chloroplasts, a vacuole and a cell wall in plant cells.
所有生物都由细胞组成，细胞分为原核细胞（无细胞核）和真核细胞（有细胞核）。动植物细胞为真核细胞，细菌为原核细胞。主要细胞器包括动物细胞中的细胞核、细胞质、细胞膜、线粒体和核糖体，植物细胞则还有叶绿体、液泡和细胞壁。
Substances move into and out of cells by diffusion, osmosis and active transport. Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, requiring no energy. Osmosis is the diffusion of water through a partially permeable membrane. Active transport moves substances against a concentration gradient, using energy from respiration.
物质通过扩散、渗透和主动运输进出细胞。扩散是粒子从高浓度区域向低浓度区域的净移动，不需要能量。渗透是水通过部分透膜的扩散。主动运输则逆浓度梯度移动物质，需消耗呼吸作用提供的能量。
2. Cell Division and Stem Cells | 细胞分裂与干细胞
Mitosis produces two genetically identical daughter cells and is used for growth, repair and asexual reproduction. The stages include interphase (DNA replication), prophase, metaphase, anaphase and telophase, followed by cytokinesis. Meiosis produces four genetically different haploid gametes, introducing variation through crossing over and independent assortment.
有丝分裂产生两个遗传上相同的子细胞，用于生长、修复和无性繁殖。其阶段包括间期（DNA复制）、前期、中期、后期和末期，随后是胞质分裂。减数分裂产生四个遗传上不同的单倍体配子，通过交叉互换和独立分配引入变异。
Stem cells are undifferentiated cells that can divide to produce more stem cells or differentiate into specialised cell types. Embryonic stem cells can become any cell type, while adult stem cells have more limited potential. Their medical applications include treating conditions such as leukaemia and spinal cord injuries, though ethical debates surround the use of embryonic stem cells.
干细胞是未分化的细胞，可分裂产生更多干细胞或分化成特化细胞类型。胚胎干细胞能分化为任何细胞类型，而成体干细胞的潜能较为有限。其医学应用包括治疗白血病和脊髓损伤等疾病，但胚胎干细胞的使用存在伦理争议。
3. Enzymes and Digestion | 酶与消化
Enzymes are biological catalysts made of protein that speed up chemical reactions without being used up. Each enzyme has an active site with a specific shape that fits its substrate, described by the lock-and-key model. Enzyme activity is affected by temperature and pH; extremes can denature the enzyme, changing the shape of the active site permanently.
酶是由蛋白质构成的生物催化剂，能加速化学反应而自身不被消耗。每种酶的活性部位具有特定形状，与底物相匹配，可用锁钥模型描述。酶活性受温度和pH影响，极端条件会使酶变性，永久改变活性部位形状。
Digestive enzymes break down large food molecules into smaller, soluble ones. Amylase (produced in salivary glands and pancreas) breaks down starch into maltose. Proteases (stomach and pancreas) break down proteins into amino acids. Lipases (pancreas and small intestine) break down lipids into fatty acids and glycerol. Bile, produced by the liver, emulsifies fats to increase the surface area for lipase action and neutralises stomach acid.
消化酶将大分子食物分解为较小的可溶性分子。淀粉酶（由唾液腺和胰腺分泌）将淀粉分解为麦芽糖。蛋白酶（胃和胰腺）将蛋白质分解为氨基酸。脂肪酶（胰腺和小肠）将脂质分解为脂肪酸和甘油。肝脏分泌的胆汁能乳化脂肪，增大脂肪酶作用的表面积，并中和胃酸。
4. The Circulatory System | 循环系统
The human 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 (pulmonary circulation), while the left side pumps oxygenated blood to the rest of the body (systemic circulation). Heart valves prevent backflow of blood.
人体循环系统由心脏、血管和血液组成。心脏是双泵：右侧将缺氧血泵至肺部（肺循环），左侧将含氧血泵至全身（体循环）。心脏瓣膜防止血液倒流。
Arteries carry blood away from the heart under high pressure and have thick muscular walls. Veins carry blood towards the heart at lower pressure and contain valves. Capillaries are one-cell thick to allow exchange of substances. Blood is composed of plasma, red blood cells (transport oxygen), white blood cells (defence) and platelets (clotting).
动脉将血液从心脏输出，管壁厚而有肌肉，承受较高压力。静脉将血液送回心脏，压力较低，含有瓣膜。毛细血管仅一层细胞厚，利于物质交换。血液由血浆、红细胞（运输氧气）、白细胞（防御）和血小板（凝血）组成。
5. Photosynthesis and Respiration | 光合作用与呼吸作用
Photosynthesis is the process by which plants and algae convert light energy into chemical energy, producing glucose and oxygen from carbon dioxide and water. The overall word equation is:
Carbon dioxide + Water → Glucose + Oxygen
光合作用是植物和藻类将光能转化为化学能的过程，利用二氧化碳和水生成葡萄糖和氧气。总文字方程式：
二氧化碳 + 水 → 葡萄糖 + 氧气
Factors affecting the rate of photosynthesis include light intensity, carbon dioxide concentration and temperature. Respiration releases energy for cellular activities. Aerobic respiration requires oxygen:
Glucose + Oxygen → Carbon dioxide + Water (+ energy)
影响光合作用速率的因素包括光照强度、二氧化碳浓度和温度。呼吸作用为细胞活动释放能量。有氧呼吸需要氧气：
葡萄糖 + 氧气 → 二氧化碳 + 水（+ 能量）
Anaerobic respiration in muscles produces lactic acid and less energy; in yeast it produces ethanol and carbon dioxide (fermentation).
肌肉中的无氧呼吸产生乳酸和较少能量；酵母中则产生乙醇和二氧化碳（发酵）。
6. Atomic Structure and the Periodic Table | 原子结构与元素周期表
Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons in shells. The atomic number is the number of protons, which determines the element. The mass number is the total number of protons and neutrons. Isotopes are atoms of the same element with different numbers of neutrons.
原子由原子核（含质子和中子）及核外按层排布的电子组成。原子序数即质子数，决定了元素种类。质量数为质子数与中子数之和。同位素是同一种元素中子数不同的原子。
The periodic table arranges elements in order of atomic number, with groups (columns) and periods (rows). Group 1 elements are the alkali metals, which are very reactive and form 1⁺ ions. Group 7 elements are the halogens, reactive non-metals forming 1⁻ ions. Group 0 elements are the noble gases, unreactive monatomic gases with full outer electron shells.
元素周期表按原子序数排列，分为族（纵列）和周期（横行）。第1族为碱金属，非常活泼，形成1⁺离子。第7族为卤族元素，是活泼的非金属，形成1⁻离子。第0族为稀有气体，是不活泼的单原子气体，具有全满的外层电子。
| Subatomic particle | Relative charge | Relative mass |
|---|---|---|
| Proton | +1 | 1 |
| Neutron | 0 | 1 |
| Electron | -1 | Negligible |
7. Chemical Bonding and Structure | 化学键与结构
Ionic bonding occurs between metals and non-metals. Electrons are transferred from the metal to the non-metal, forming positive and negative ions that attract each other in a giant ionic lattice. Ionic compounds have high melting points and conduct electricity when molten or dissolved.
离子键存在于金属和非金属之间。电子从金属转移到非金属，形成正负离子，它们在巨大的离子晶格中相互吸引。离子化合物熔点高，在熔融或溶解状态下能导电。
Covalent bonding happens when non-metal atoms share pairs of electrons to achieve full outer shells. Simple molecular substances have low melting points because of weak intermolecular forces, while giant covalent structures like diamond and graphite have high melting points. Graphite conducts electricity due to delocalised electrons between layers.
共价键是非金属原子通过共用电子对以达到满外层的成键方式。简单分子物质因分子间作用力弱而熔点低，而金刚石和石墨等巨型共价结构熔点高。石墨由于层间存在离域电子而能导电。
Metallic bonding involves a lattice of positive ions surrounded by a sea of delocalised electrons. This explains the properties of metals: good electrical and thermal conductors, malleable and ductile.
金属键包含正离子晶格，周围有离域电子的海洋。这解释了金属的性质：优良的电和热导体、可锻性和延展性。
8. Quantitative Chemistry | 定量化学
Relative atomic mass (Ar) is the average mass of an atom of an element compared to 1/12th the mass of carbon-12. Relative formula mass (Mr f substance; one mole of any substance contains 6.02 × 10²³ particles (Avogadro constant).
相对原子质量（Ar）是某元素一个原子的平均质量与碳-12原子质量的1/12之比。相对式量（Mr）是化学式中所有原子的相对原子质量之和。摩尔是物质的量的单位，1摩尔任何物质含有6.02×10²³个微粒（阿伏伽德罗常数）。
The mass of one mole of a substance is its molar mass in g/mol. Calculations often use the relationship:
Mass = Moles × Molar mass
Using balanced equations, the mole ratio can be used to calculate reacting masses. Concentration of a solution is measured in mol/dm³ or g/dm³.
一摩尔物质的质量为其摩尔质量，单位g/mol。计算常用关系式：
质量 = 摩尔数 × 摩尔质量
使用配平方程式，可通过摩尔比计算反应质量。溶液浓度单位是mol/dm³或g/dm³。
9. 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 following the decrease in reactant concentration, increase in product concentration, or change in mass or volume of a gas over time. Factors increasing the rate include higher temperature, increased concentration (or pressure for gases), larger surface area of solids, and the presence of a catalyst.
化学反应速率可通过监测反应物浓度的降低、生成物浓度的增加或气体质量/体积随时间的变化来测量。提高速率的因素包括：升高温度、增大浓度（或气体压强）、增加固体的表面积以及使用催化剂。
Collision theory explains that particles must collide with sufficient energy and correct orientation for a reaction to occur. Increasing temperature gives particles more kinetic energy and more frequent collisions. A catalyst provides an alternative reaction pathway with a lower activation energy.
碰撞理论认为，粒子必须发生有效碰撞——具有足够能量和正确方向才能反应。升高温度使粒子动能增加，碰撞更频繁。催化剂提供一条活化能更低的新反应路径。
Exothermic reactions transfer energy to the surroundings (temperature rise), for example combustion and neutralisation. Endothermic reactions absorb energy from the surroundings (temperature drop), such as thermal decomposition. Reaction profiles show the enthalpy change and activation energy.
放热反应向环境释放能量（温度上升），例如燃烧和中和反应。吸热反应从环境吸收能量（温度下降），例如热分解。反应剖面图展示焓变和活化能。
10. Electricity and Circuits | 电学与电路
Electric current is the flow of electric charge. In metals, current is a flow of electrons; in electrolytes, it is a flow of ions. Current (I) is measured in amperes (A), potential difference (V) in volts (V), and resistance (R) in ohms (Ω). Ohm's Law states:
V = I × R
电流是电荷的流动。在金属中，电流是电子流；在电解液中，是离子流。电流（I）以安培（A）为单位，电势差（V）以伏特（V）为单位，电阻（R）以欧姆（Ω）为单位。欧姆定律：
V = I × R
In a series circuit, the current is the same everywhere, but the total resistance is the sum of individual resistances. In a parallel circuit, the potential difference across each branch is the same, and the total current is the sum of branch currents. Components such as resistors, diodes and thermistors have characteristic I-V graphs.
串联电路中电流处处相等，总电阻为各电阻之和。并联电路中各支路电势差相等，总电流为支路电流之和。电阻器、二极管和热敏电阻等元件具有特定的I-V特性曲线。
electricity uses alternating current (a.c.) while batteries supply direct current (d.c.).
电路中的功率（P）由 P = I × V 给出，传输能量 E = P × t。家庭用电使用交流电（a.c.），而电池提供直流电（d.c.）。
11. Forces and Motion | 力与运动
Forces are pushes or pulls measured in newtons (N). Newton's laws of motion describe how objects behave under forces. The first law states that an object will remain at rest or move with constant velocity unless acted upon by a resultant force. The second law relates force, mass and acceleration:
F = m × a
力是推或拉，单位为牛顿（N）。牛顿运动定律描述了物体在力作用下的行为。第一定律：除非受到合力，物体将保持静止或匀速直线运动。第二定律将力、质量和加速度关联起来：
F = m × a
Velocity is speed in a given direction; acceleration is the rate of change of velocity. Motion can be represented on distance–time and velocity–time graphs. The gradient of a velocity–time graph gives acceleration, and the area under the graph gives distance travelled.
速度是带有方向的速率，加速度是速度的变化率。运动可用距离–时间图和速度–时间图表示。速度–时间图的斜率表示加速度，图下的面积表示行驶距离。
Stopping distance of a vehicle consists of thinking distance and braking distance. Factors affecting braking distance include road conditions, speed, tyre conditions and brake wear. Momentum is the product of mass and velocity; in a closed system, total momentum before a collision equals total momentum after (conservation of momentum).
汽车的停车距离由思考距离和制动距离组成。影响制动距离的因素有路面状况、车速、轮胎状况和刹车磨损。动量是质量与速度的乘积；在封闭系统中，碰撞前的总动量等于碰撞后的总动量（动量守恒）。
12. Waves and Electromagnetic Spectrum | 波与电磁波谱
Waves transfer energy without transferring matter. Transverse waves (e.g. light, ripples on water) have oscillations perpendicular to the direction of energy transfer. Longitudinal waves (e.g. sound) have oscillations parallel to the direction of energy transfer, consisting of compressions and rarefactions.
波传递能量而不传递物质。横波（如光、水波）的振动方向与能量传递方向垂直。纵波（如声波）的振动方向与能量传递方向平行，由压缩和稀疏区域组成。
es and radio waves. All travel at the speed of light in a vacuum (3.0 × 10⁸ m/s). Wave speed is related to frequency and wavelength:
v = f × λ
电磁波谱按波长递增的顺序包括伽马射线、X射线、紫外线、可见光、红外线、微波和无线电波。它们在真空中均以光速（3.0 × 10⁸ m/s）传播。波速与频率和波长的关系：
v = f × λ
Different types of electromagnetic radiation have various applications, from medical imaging (X-rays) to communication (radio waves) and cooking (microwaves). Dangerous high-energy radiation like ultraviolet, X-rays and gamma rays can cause ionisation, damage cells and increase cancer risk.
不同种类的电磁辐射有各种应用，从医学成像（X射线）到通讯（无线电波）和烹饪（微波）。紫外线、X射线和伽马射线等高能危险辐射可引起电离，损伤细胞，增加癌症风险。
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