📚 Year 8 WJEC Biology: Formulas & Theorems Quick Reference | Year 8 WJEC 生物：公式定理速查手册
This revision guide compiles the essential formulas, equations, and fundamental theories you will encounter in Year 8 WJEC Biology. Mastering these key ideas will help you analyse data, explain life processes, and solve quantitative problems with confidence.
本复习指南汇总了你在 Year 8 WJEC 生物学课程中将遇到的基本公式、方程式和核心理论。掌握这些关键思想将帮助你分析数据、解释生命过程，并自信地解决定量问题。
1. The Cell Theory | 细胞理论
All living organisms are composed of one or more cells, and the cell is the basic unit of structure and organisation in living things. All cells arise from pre-existing cells through cell division.
所有生物体都由一个或多个细胞组成，细胞是生命体结构与组织的基本单位。所有细胞都通过细胞分裂从已有细胞产生。
The theory was developed by scientists such as Schleiden, Schwann, and Virchow. It underpins all of modern biology and reminds us that viruses, which are not made of cells, are not considered alive.
该理论由施莱登、施万和菲尔肖等科学家发展而来。它支撑着整个现代生物学，并提醒我们，病毒不是由细胞构成的，因此不被视为生物。
2. Magnification Formula | 放大倍率公式
When using a light microscope, the total magnification is calculated by multiplying the power of the eyepiece lens by the power of the objective lens.
使用光学显微镜时，总放大倍率由目镜倍数乘以物镜倍数计算得出。
Total Magnification = Eyepiece Magnification × Objective Magnification
For example, a 10x eyepiece and a 40x objective give a total magnification of 400x. You can also rearrange the formula to calculate the real size of a specimen:
例如，10倍目镜和40倍物镜的总放大倍率为400倍。你还可以重新排列公式来计算标本的实际大小：
Real Size = Image Size ÷ Magnification
Remember to convert units carefully (1 mm = 1000 µm) when working with cell measurements.
在进行细胞测量时，请仔细换算单位（1 毫米 = 1000 微米）。
3. Photosynthesis Word Equation | 光合作用文字方程式
Photosynthesis is the process in which green plants and some microorganisms use light energy to synthesise glucose from carbon dioxide and water, releasing oxygen as a by-product.
光合作用是绿色植物和某些微生物利用光能，由二氧化碳和水合成葡萄糖，并释放出氧气作为副产物的过程。
Carbon Dioxide + Water → Glucose + Oxygen
asts. The balanced symbol equation (useful for extension) is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.
光能被叶绿体中的叶绿素吸收。平衡的符号方程式（拓展知识）为：6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂。
The rate of photosynthesis can be affected by light intensity, carbon dioxide concentration, and temperature. The factor in shortest supply acts as the limiting factor.
光合作用的速率受光照强度、二氧化碳浓度和温度的影响。供应最短缺的那个因素就是限制因子。
4. Aerobic Respiration Equation | 有氧呼吸方程式
Aerobic respiration releases energy from glucose using oxygen. It occurs continuously in the mitochondria of most cells.
有氧呼吸借助氧气从葡萄糖中释放能量。它持续发生在大多数细胞的线粒体中。
Glucose + Oxygen → Carbon Dioxide + Water
ased is used to form ATP, which powers cellular activities such as muscle contraction and active transport.
平衡符号方程式为 C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O。释放的能量用于形成 ATP，为肌肉收缩和主动运输等细胞活动供能。
5. Anaerobic Respiration Equations | 无氧呼吸方程式
When oxygen is scarce, cells can respire anaerobically to release a smaller amount of energy. The products differ between organisms.
当氧气不足时，细胞可以进行无氧呼吸，释放少量能量。产物因生物体而异。
In human muscle cells: scle fatigue and cramps. The lactic acid is later transported to the liver to be broken down when oxygen becomes available (oxygen debt).
在人体肌肉细胞内：葡萄糖 → 乳酸。这会导致肌肉疲劳和抽筋。乳酸随后被运送到肝脏，待氧气充足时被分解（氧债）。
In yeast (fermentation): bon Dioxide. This process is economically important for making bread and alcoholic drinks.
在酵母（发酵）中：葡萄糖 → 乙醇 + 二氧化碳。这一过程在制作面包和酒精饮品中具有重要经济价值。
6. Lock and Key Theorem for Enzymes | 酶的锁钥定理
Enzymes are biological catalysts that speed up chemical reactions. The lock and key model explains enzyme specificity: the substrate fits into the enzyme's active site like a key into a lock.
酶是加速化学反应的生物催化剂。锁钥模型解释了酶的专一性：底物像一把钥匙插入锁一样，进入酶的活性部位。
Substrate + Enzyme → Enzyme–Substrate Complex → Products + Enzyme (unchanged)
Each enzyme works best at an optimum temperature and pH. High temperatures denature the enzyme by changing the shape of its active site permanently. This theorem is crucial when designing experiments with amylase, protease, or catalase.
每种酶都有一个最适温度和最适 pH 值。高温会永久改变酶活性部位的形状，使其变性。在用淀粉酶、蛋白酶或过氧化氢酶设计实验时，这一原理至关重要。
7. Calorimetry: Energy Content of Food | 量热法：食物能量含量
The energy stored in food can be estimated by burning a sample and measuring the temperature rise of a known volume of water. This simple calorimetry uses the specific heat capacity of water (4.2 J/g°C).
食物中储存的能量可以通过燃烧样品并测量已知体积水的温度升高来估算。这种简单的量热法利用了水的比热容（4.2 J/g°C）。
Energy (J) = Mass of Water (g) × 4.2 × Temperature Rise (°C)
To find the energy per gram of food, divide the energy by the mass of food burnt. Reliable results require good insulation, stirring, and repeating trials.
要找出每克食物所含能量，用所得能量除以燃烧的食物质量。获得可靠结果需要良好的隔热、搅拌和重复试验。
8. Mendel's Laws of Inheritance | 孟德尔遗传定律
Gregor Mendel discovered basic principles of heredity by crossing pea plants. His Law of Segregation states that each organism carries two alleles for each trait, and these alleles separate during gamete formation so each gamete carries only one allele.
格雷戈尔·孟德尔通过豌豆杂交实验发现了遗传的基本原理。他的分离定律指出，每个性状在生物体中由两个等位基因控制，这些等位基因在配子形成时分离，使每个配子只携带一个等位基因。
For a monohybrid cross, Punnett squares are used to predict the probability of offspring genotypes:
对于单基因杂交，使用旁氏表来预测后代基因型的概率：
Probability of a Specific Genotype = Number of Relevant Boxes ÷ 4
For example, crossing two heterozygous parents (Bb × Bb) gives a 25% chance of 'bb', 50% chance of 'Bb', and 25% chance of 'BB'. This helps explain 3:1 phenotypic ratios for dominant/recessive traits.
例如，两个杂合亲本（Bb × Bb）杂交，后代出现 'bb' 的概率为 25%，'Bb' 概率为 50%，'BB' 概率为 25%。这可以解释显性/隐性性状中 3:1 的表型比。
9. Quadrat Sampling and Population Estimation | 样方抽样与种群估算
To estimate the population of organisms in a habitat, you can use a quadrat (a square frame) to collect sample counts. This method works well for plants and slow-moving animals.
要估算栖息地中生物的数量，你可以使用样方（一个方框）进行取样计数。这种方法很适合植物和移动缓慢的动物。
Estimated Population = Mean Count per Quadrat × (Total Area ÷ Quadrat Area)
Random sampling is achieved by using random number coordinates. The more quadrats you place, the more reliable your estimate. Percentage cover can also be used as an alternative measure of abundance.
通过使用随机数坐标来实现随机取样。放置的样方越多，你的估算就越可靠。盖度百分比也可作为多度的替代指标。
10. Respiratory Gas Exchange and Diffusion | 呼吸气体交换与扩散
Although not a formula, the principle of diffusion is a core theorem: particles move from an area of high concentration to an area of low concentration, down a concentration gradient. This explains how oxygen enters the blood from the alveoli and how carbon dioxide leaves.
虽然不是一个公式，但扩散原理是一条核心定理：粒子沿浓度梯度从高浓度区域向低浓度区域移动。这解释了氧气如何从肺泡进入血液，以及二氧化碳如何离开。
Several adaptations of the alveoli make diffusion efficient: a large surface area, thin walls (one cell thick), moist lining, and a rich supply of blood capillaries. The rate of diffusion increases with a steeper concentration gradient, higher temperature, and larger surface area.
肺泡的多个适应特征使扩散更高效：表面积大、管壁薄（仅一个细胞厚）、湿润的内膜和丰富的毛细血管供血。扩散速率随浓度梯度变陡、温度升高和表面积增大而增加。
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