📚 KS3 CCEA Biology: Formula & Theorem Quick Reference Handbook | KS3 CCEA 生物：公式定理速查手册
This handbook provides a concise summary of essential formulas, word equations and biological principles covered in the KS3 CCEA Biology curriculum. Designed for quick revision, it brings together the key relationships you need to recall for practical investigations, end-of-topic tests and progression to GCSE work. Each entry is presented with a clear English explanation followed by a matching Chinese translation, along with centrally highlighted equations where appropriate.
本手册简要总结了 KS3 CCEA 生物课程中涉及的重要公式、词方程式和生物学原理，专为快速复习设计。它将实验探究、单元测验以及进阶到 GCSE 所需的关键关系集中在一起。每个条目都先给出清晰的英文解释，再配以对应的中文翻译，并在合适的地方用居中加粗的方式突出方程式。
1. Microscope Magnification Formula | 显微镜放大倍率公式
The total magnification of a light microscope is found by multiplying the magnifying power of the eyepiece lens by that of the objective lens being used. Always read the markings on the lens barrels before you calculate.
光学显微镜的总放大倍率是目镜放大倍率与所用物镜放大倍率的乘积。计算前务必先读取镜筒上的放大倍数标记。
Total Magnification = Eyepiece Magnification x Objective Magnification
For example, a x10 eyepiece combined with a x40 objective gives a total magnification of x400. If you switch to a x4 objective, the total becomes x40, which is useful for scanning a larger area of the slide.
例如，x10 目镜配合 x40 物镜可得到 x400 的总放大率。若换用 x4 物镜，总放大率变为 x40，这适宜于扫描玻片上较大区域的样品。
2. Photosynthesis Word Equation | 光合作用词方程式
Photosynthesis is the fundamental process by which green plants and algae trap light energy to build glucose, their main energy store. Chlorophyll inside chloroplasts is essential for capturing the light, and the overall reaction can be written as a simple word equation.
光合作用是绿色植物和藻类截获光能以合成其主要储能物质——葡萄糖的基础过程。叶绿体中的叶绿素是捕获光能的关键，整个反应可写成简单的词方程式。
carbon dioxide + water → glucose + oxygen
The arrow can be labelled ‘light energy’ above and ‘chlorophyll’ below to show the conditions required. In symbols, the balanced equation is: 6CO2 + 6H2O → C6H12O6 + 6O2. This reminds you that the atoms on each side are equal.
箭头通常上方标注“光能”、下方标注“叶绿素”，以标明反应条件。用符号表示时，配平方程式为：6CO2 + 6H2O → C6H12O6 + 6O2，可帮你记住反应前后原子数目守恒。
3. Aerobic Respiration Word Equation | 有氧呼吸词方程式
Aerobic respiration is the chemical process that releases energy from glucose in the presence of oxygen. It takes place continuously in the mitochondria of most cells and supplies energy for all life processes, from muscle contraction to active transport.
有氧呼吸是在有氧条件下从葡萄糖释放能量的化学过程，它持续发生在大多数细胞的线粒体中，为肌肉收缩、主动运输等所有生命活动提供能量。
glucose + oxygen → carbon dioxide + water (+ energy)
The energy released is used to form ATP. The balanced symbol equation is exactly the reverse of photosynthesis: C6H12O6 + 6O2 → 6CO2 + 6H2O. Note that carbon dioxide and water are waste products that must be removed.
释放的能量用于合成 ATP。配平后的符号方程式恰好是光合作用的逆向反应：C6H12O6 + 6O2 → 6CO2 + 6H2O。请注意二氧化碳和水都是必须被清除的代谢废物。
4. Anaerobic Respiration Word Equations | 厌氧呼吸词方程式
When oxygen supply is insufficient, cells can respire anaerobically to obtain a small amount of energy. In animals, this produces lactic acid and causes muscle fatigue, while in yeast and some plants it yields ethanol and carbon dioxide.
当氧气供应不足时，细胞进行厌氧呼吸以获取少量能量。动物体中该过程产生乳酸并导致肌肉酸胀，而酵母及某些植物则生成乙醇和二氧化碳。
In animals: glucose → lactic acid (+ energy)
Anaerobic respiration in humans is a short‑term measure; lactic acid is later oxidised back to safe compounds when oxygen is available again. This is why you continue to breathe heavily after strenuous exercise.
人体的厌氧呼吸是短期应急机制；乳酸随后在供氧恢复时被氧化回无害物质。这正是剧烈运动后仍会大口喘气的原因。
In yeast & plants: glucose → ethanol + carbon dioxide (+ energy)
The production of ethanol by yeast is exploited in brewing and baking. This form of anaerobic respiration is also called fermentation, and the carbon dioxide released causes dough to rise.
酵母产生乙醇的过程被用于酿酒和烘焙。这种厌氧呼吸也称发酵，所释放的二氧化碳使面团膨胀。
5. Enzyme Action and the Lock‑and‑Key Model | 酶的作用与锁钥模型
Enzymes are biological catalysts that speed up metabolic reactions without being used up. The lock‑and‑key model explains their specificity: the active site of an enzyme has a precise shape that only fits a specific substrate, like a key fitting into a lock.
酶是生物催化剂，能加速代谢反应而自身不被消耗。锁钥模型解释了酶的专一性：酶的活性部位具有精确形状，只与特定底物匹配，恰如钥匙插入对应的锁。
Each enzyme works best at its optimum temperature and pH. For most human enzymes the optimum temperature is around 37 °C and the optimum pH depends heavily on the site of action, e.g. stomach pepsin prefers acidic conditions whereas intestinal enzymes work best in slightly alkaline surroundings.
每种酶都在其最适温度和最适 pH 下发挥最高效率。人体大多数酶的最适温度约 37 °C，而最适 pH 因作用部位而异：胃蛋白酶喜酸性环境，而小肠中的酶在弱碱性条件下活性最佳。
Enzyme + Substrate → Enzyme‑Substrate Complex → Enzyme + Products
Understanding this model helps explain why high temperatures denature enzymes – the active site loses its complementary shape permanently. Changes in pH can also alter the shape of the active site, reducing catalytic ability.
理解该模型可以解释高温为何使酶变性——活性部位永久失去互补形状。pH 的变化同样能改变活性部位构型，削弱催化能力。
6. Digestive Enzyme Reactions | 消化酶的酶解反应
Large food molecules such as starch, proteins and lipids are broken down by specific digestive enzymes into smaller, soluble molecules that can pass through the gut wall into the bloodstream. These reactions are examples of hydrolysis and can be summarised as word equations.
淀粉、蛋白质和脂类等大分子食物被特定消化酶分解为可透过肠壁进入血液的小分子可溶性物质。这些反应属于水解反应，可用词方程式概括。
Amylase: starch → maltose (and further into glucose)
Amylase is produced in the salivary glands and the pancreas. It begins starch digestion in the mouth, and the resulting sugars supply a rapid energy source once absorbed.
淀粉酶由唾液腺和胰腺分泌，在口腔即开始分解淀粉。生成的糖类被吸收后可快速提供能量。
Protease: protein → amino acids
Proteases such as pepsin (stomach) and trypsin (small intestine) hydrolyse the peptide bonds in proteins. The amino acids released are used by cells to build new proteins for growth and repair.
胃蛋白酶（胃）和胰蛋白酶（小肠）等蛋白酶将蛋白质中的肽键水解。释放出的氨基酸被细胞用于合成新蛋白质，支持生长和修复。
Lipase: lipids → fatty acids + glycerol
Lipase works primarily in the small intestine. Bile, produced by the liver and stored in the gall bladder, emulsifies fats to increase the surface area, making lipase’s action much more efficient.
脂肪酶主要在小肠发挥作用。肝脏分泌并储存于胆囊的胆汁能乳化脂肪，增大表面积，从而显著提高脂肪酶的分解效率。
7. Energy Transfer and Biomass in Food Chains | 食物链中的能量传递与生物量
Energy enters most ecosystems as sunlight and is converted by producers (plants) into biomass via photosynthesis. At each step in a food chain, energy is lost through movement, heat and undigested materials, so only a small fraction reaches the next trophic level.
能量以阳光形式进入大多数生态系统，生产者（植物）通过光合作用将其转化为生物量。在食物链的每一环节，能量因运动、散热和未消化物质而损耗，因此只有一小部分传递至下一个营养级。
Energy available to next level ≈ 10% of energy consumed
Although the exact percentage varies, the 10% rule is a useful approximation. This explains why food chains rarely have more than four or five trophic levels and why pyramids of biomass and energy are almost always upright.
尽管精确百分比有所变化，10% 法则是一个方便的近似值。这也解释了为何食物链通常不超过四到五个营养级，以及生物量金字塔和能量金字塔几乎总是呈正立形态。
Efficiency can be calculated as: (energy in new biomass ÷ energy taken in) × 100%. Improving efficiency in livestock farming means reducing energy loss so that more biomass is transferred to the human food chain.
传递效率可按（新生物量所含能量 ÷ 摄入能量）× 100% 计算。发展畜牧业时提高效率就是减少能量损失，使更多生物量进入人类食物链。
8. Diffusion and Osmosis Principles | 扩散与渗透原理
Diffusion is the passive net movement of particles from a region of higher concentration to a region of lower concentration, down the concentration gradient. It requires no metabolic energy and is vital for gas exchange in lungs and leaves.
扩散是粒子沿浓度梯度由高浓度区域向低浓度区域的被动净移动，不消耗代谢能，对肺和叶的气体交换至关重要。
Rate of diffusion ∝ (Surface area × Concentration difference) ÷ Diffusion distance
Therefore, alveoli and leaf mesophyll cells have large surface areas, thin membranes and steep concentration gradients to maximise the rate of diffusion. This relationship is a key principle when interpreting how organisms are adapted for exchange.
因此，肺泡和叶肉细胞拥有大表面积、薄膜和巨大的浓度差，以最大化扩散速率。这一关系是理解生物如何适应物质交换的关键原理。
Osmosis is a special case of diffusion involving water molecules moving through a selectively permeable membrane from a region of high water potential (dilute solution) to a region of lower water potential (more concentrated solution). It is crucial for water uptake in plant roots and for maintaining cell turgor.
渗透是扩散的一种特殊情况，指水分子通过选择透过性膜从高水势（稀溶液）向低水势（浓溶液）区域移动。它对植物根吸水和维持细胞膨压意义重大。
9. Calculating Photosynthesis Rate | 光合作用速率的测定
The rate of photosynthesis can be measured indirectly by tracking oxygen production or carbon dioxide consumption over a fixed time. The standard formula used in practical work is based on volume of gas produced per unit time.
光合作用速率可通过追踪固定时间内氧气的产生量或二氧化碳的消耗量间接测量。实验操作中常用的公式基于单位时间内产生的气体体积。
Rate of photosynthesis = Volume of oxygen produced (cm³) ÷ Time (min)
In a typical pondweed (Elodea) experiment, you can count the number of bubbles released per minute. Counting for 2–3 minutes and averaging the results yields a more reliable estimate. The relationship can be explored by varying light intensity, carbon dioxide concentration or temperature.
在典型的水蕴草实验中，可计数每分钟释放的气泡数目。连续计数 2–3 分钟并取平均值能得到更可靠的估计。通过改变光照强度、二氧化碳浓度或温度，可以探究这些因素与光合速率的关系。
10. MRS GREN: The Seven Life Processes | 七大生命过程：MRS GREN 记忆口诀
Although not a formula in the mathematical sense, MRS GREN is an essential conceptual framework that defines living organisms. All living things carry out these seven processes, which can be remembered by the acronym MRS GREN.
尽管不是数学意义上的公式，MRS GREN 却是界定生物体的基本概念框架。所有生物都执行这七大过程，可用首字母缩写 MRS GREN 来记忆。
Movement – Respiration – Sensitivity – Growth – Reproduction – Excretion – Nutrition
Movement: an action by an organism causing a change of position or place. Respiration: the release of energy from food. Sensitivity: detecting and responding to stimuli in the environment. Growth: a permanent increase in size and dry mass. Reproduction: producing new individuals of the same species. Excretion: removing metabolic waste products. Nutrition: obtaining food for energy, growth and repair.
运动：生物体引起位置或地点改变的行为；呼吸：从食物中释放能量；感应：探测并回应环境刺激；生长：体积和干质量的永久增加；生殖：产生同种新个体；排泄：清除代谢废物；营养：摄取养分以提供能量、支持生长和修复。
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