📚 Year 8 CCEA Biology: Formula & Theorem Quick Reference Handbook | CCEA 八年级生物：公式定理速查手册
This handbook gathers every essential equation, formula, and theorem you need for Year 8 CCEA Biology. Whether you are calculating magnification, balancing photosynthesis, or recalling enzyme conditions, this revision tool puts the key facts at your fingertips.
本手册汇集了 CCEA 八年级生物必需掌握的所有重要方程、公式和定理。无论你是在计算放大倍数、配平光合作用方程，还是回忆酶的作用条件，这本复习工具都能让你快速找到关键知识点。
1. Photosynthesis Word Equation | 光合作用文字方程
Photosynthesis is the process by which green plants make their own food using light energy.
光合作用是绿色植物利用光能制造自身养料的过程。
The word equation summarises the reactants and products:
文字方程概括了反应物和生成物：
Carbon dioxide + Water → Glucose + Oxygen
二氧化碳 + 水 → 葡萄糖 + 氧气
Light energy is absorbed by chlorophyll in chloroplasts to drive the reaction.
光能被叶绿体中的叶绿素吸收，驱动反应进行。
Glucose is stored as starch temporarily; some is used for respiration.
葡萄糖暂时以淀粉形式储存；一部分用于呼吸作用。
2. Aerobic Respiration Word Equation | 有氧呼吸文字方程
Respiration releases energy from glucose in all living cells.
呼吸作用在所有活细胞中分解葡萄糖释放能量。
Aerobic respiration requires oxygen and produces carbon dioxide and water as waste.
有氧呼吸需要氧气，并产生二氧化碳和水作为废物。
Glucose + Oxygen → Carbon dioxide + Water + Energy (ATP)
葡萄糖 + 氧气 → 二氧化碳 + 水 + 能量（ATP）
This takes place in mitochondria.
这发生在线粒体中。
Energy is used for movement, growth, and keeping warm.
能量用于运动、生长和维持体温。
3. Anaerobic Respiration in Humans (Word Equation) | 人体无氧呼吸（文字方程）
When oxygen is limited, muscle cells switch to anaerobic respiration.
当氧气不足时，肌肉细胞转为无氧呼吸。
It produces lactic acid and much less energy.
它产生乳酸和少得多的能量。
Glucose → Lactic acid + Energy
葡萄糖 → 乳酸 + 能量
Lactic acid builds up and causes muscle fatigue and cramps.
乳酸堆积会引起肌肉疲劳和抽筋。
Oxygen debt is the extra oxygen needed after exercise to break down the lactic acid.
氧债是运动后分解乳酸所需的额外氧气。
4. Anaerobic Respiration in Yeast (Fermentation) | 酵母菌的无氧呼吸（发酵）
Yeast and some microorganisms produce ethanol and carbon dioxide instead of lactic acid.
酵母和某些微生物产生乙醇和二氧化碳，而非乳酸。
Glucose → Ethanol + Carbon dioxide + Energy
葡萄糖 → 乙醇 + 二氧化碳 + 能量
This is used in baking (CO₂ makes bread rise) and brewing (ethanol).
这用于烘焙（CO₂ 使面包发酵）和酿酒（乙醇）。
Yeast cells can switch to aerobic respiration when oxygen is present.
有氧气时，酵母细胞可切换为有氧呼吸。
5. Microscope Magnification Formula | 显微镜放大倍数公式
Calculating total magnification is a core skill in CCEA Biology.
计算总放大倍数是 CCEA 生物的核心技能。
Total Magnification = Eyepiece lens magnification × Objective lens magnification
总放大倍数 = 目镜放大倍数 × 物镜放大倍数
Common eyepiece: ×10; objectives: ×4, ×10, ×40.
常见目镜：×10；物镜：×4、×10、×40。
Example: 10 × 40 = ×400 total magnification.
例：10 × 40 = ×400 总放大倍数。
To calculate real cell size, use:
计算实际细胞尺寸，使用：
Real size = Image size ÷ Magnification
实际大小 = 图像大小 ÷ 放大倍数
Teach yourself to convert units: 1 mm = 1000 µm.
学会单位换算：1 毫米 = 1000 微米。
6. Enzyme Activity – Lock and Key Model | 酶活性 – 锁钥模型
Enzymes are biological catalysts that speed up reactions without being used up.
酶是生物催化剂，能加速反应而本身不被消耗。
The 'lock and key' theorem states:
“锁钥模型”定理指出：
Every enzyme has an active site shaped specifically for its substrate (key).
每种酶都有一个特定形状的活性位点，只与底物（钥匙）匹配。
Substrate fits into the active site, forming an enzyme-substrate complex.
底物嵌入活性位点，形成酶-底物复合物。
Reaction occurs, products are released, enzyme remains unchanged.
反应发生，产物释放，酶保持不变。
Enzymes are denatured by high temperatures or extreme pH, changing the shape of the active site permanently.
高温或极端 pH 会使酶变性，永久改变活性位点的形状。
7. Optimum Conditions for Enzymes | 酶的最适条件
Each enzyme works best at a specific temperature and pH – this is its optimum.
每种酶在特定的温度和 pH 下工作效率最高——这就是其最适条件。
| Enzyme | Optimum Temperature | Optimum pH |
|---|---|---|
| Human amylase | 37 °C (body temp) | pH 7 (neutral) |
| Pepsin (stomach) | 37 °C | pH 2 (acidic) |
| Plant enzymes (e.g., catalase) | ~20-25 °C | pH 7-8 |
Understanding these conditions helps explain why high fever or changes in pH can stop metabolic reactions.
理解这些条件有助于解释为什么高烧或 pH 改变会停止代谢反应。
8. Diffusion Theorem | 扩散定理
Diffusion is the net movement of particles from a region of high concentration to a region of low concentration, down a concentration gradient.
扩散是粒子从高浓度区域向低浓度区域的净运动，沿浓度梯度进行。
It is a passive process — no energy is needed.
这是被动过程——不需要能量。
Rate of diffusion increases with higher temperature, steeper gradient, and larger surface area.
温度越高、浓度梯度越陡、表面积越大，扩散速率越快。
Examples: oxygen entering blood in lungs, carbon dioxide leaving, nutrients absorbed by cells.
例子：氧气进入肺部血液，二氧化碳排出，营养物质被细胞吸收。
9. Osmosis – A Special Case of Diffusion | 渗透——扩散的一种特殊情况
Osmosis is the diffusion of water molecules through a partially permeable membrane from a dilute solution to a more concentrated solution.
渗透是水分子通过部分透性膜从稀溶液向较浓溶液扩散的过程。
No energy is required.
不需要能量。
Plant cells in pure water become turgid (firm) because water enters by osmosis.
植物细胞在纯水中因水分进入而膨胀（变得坚挺）。
In a concentrated sugar/salt solution, plant cells lose water and become flaccid (plasmolysis).
在浓糖/盐溶液中，植物细胞失水变得萎蔫（质壁分离）。
Animal cells can burst (lysis) in pure water if too much water enters — they lack a cell wall.
动物细胞在纯水中如果进水过多会破裂（溶胞）——它们缺乏细胞壁。
10. Food Chain Energy Transfer and the 10% Rule | 食物链能量传递与百分之十定律
In any food chain, energy is transferred from one trophic level to the next, but most is lost.
在任何食物链中，能量从一个营养级传递到下一个，但大部分能量会损失。
Energy available at next level ≈ 10% of energy at previous level
下一营养级可用的能量 ≈ 上一营养级能量的 10%
Losses occur through movement, heat, uneaten parts, and excretion.
损失途径包括运动、散热、未被食用的部分以及排泄。
About 90% of energy is lost between levels, which explains why food chains rarely have more than 4-5 links.
营养级间大约 90% 能量损失，这解释了为什么食物链很少有超过 4-5 个环节。
Pyramids of energy or biomass represent this transfer.
能量金字塔或生物量金字塔可表示这种传递。
11. Photosynthesis Limiting Factors Summary | 光合作用限制因素总结
The rate of photosynthesis is limited by the factor that is in shortest supply.
光合作用速率受供应最少的因素限制。
| Factor | Effect |
|---|---|
| Light intensity | Up to a point, more light increases rate. Beyond saturation, no effect. |
| Carbon dioxide concentration | Rising CO₂ boosts rate until another factor becomes limiting. |
| Temperature | Enzymes work faster up to optimum; too high causes denaturation. |
The theorem: the factor that is lowest relative to the plant's need will be the limiting factor at any given moment.
定理：相对于植物的需求而言，数值最低的那个因素在特定时刻就是限制因素。
12. Key Biological Units and Symbols Quick Guide | 关键生物单位与符号速查
Memorise these frequently used units and symbols to avoid mistakes in calculations and graphs.
熟记这些常用单位和符号，可避免计算和图表中的错误。
Length: 1 centimetre (cm) = 10 millimetres (mm); 1 mm = 1000 micrometres (µm)
长度：1 厘米 (cm) = 10 毫米 (mm)；1 毫米 = 1000 微米 (µm)
Temperature: °C (degrees Celsius)
温度：°C（摄氏度）
Energy: kilojoules (kJ)
能量：千焦 (kJ)
Magnification: × (times)
放大倍数：×（倍）
Biomass: grams per square metre (g/m²)
生物量：克每平方米 (g/m²)
Using correct units turns a one-mark guess into a confident, full-mark answer.
使用正确的单位能将碰运气的答案变成有信心拿满分的解答。
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