📚 Year 8 AQA Biology: Quick Reference Formula & Theorem Handbook | 八年级 AQA 生物：公式定理速查手册
This concise handbook gathers all the essential formulas, equations, and key theorems you will encounter in Year 8 AQA Biology. Use it for quick revision, homework help, and exam preparation. Every topic is presented in a simple bilingual format to support learners at all levels.
这本速查手册汇集了八年级 AQA 生物课程中所有重要的公式、方程式和关键定理。可用于快速复习、巩固作业和备考冲刺。每个主题都以简洁的中英双语形式呈现，便于不同水平的学生高效掌握。
1. Microscopy Magnification | 显微镜放大倍数
The total magnification of a microscope is found by multiplying the magnification of the eyepiece lens by the magnification of the objective lens.
显微镜的总放大倍数等于目镜放大倍数与物镜放大倍数的乘积。
Total magnification = Eyepiece magnification × Objective magnification
总放大倍数 = 目镜放大倍数 × 物镜放大倍数
ification of ×10 and the objective lens is ×40, the total magnification is 10 × 40 = ×400.
例如，目镜放大10倍，物镜放大40倍，总放大倍数为 10 × 40 = 400倍。
2. Photosynthesis Word Equation | 光合作用单词方程式
Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesise nutrients from carbon dioxide and water. The word equation summarises the reactants and products.
光合作用是绿色植物及某些生物利用光能，以二氧化碳和水为原料合成营养物质的过程。单词方程式概括了反应物与生成物。
Carbon dioxide + Water → Glucose + Oxygen
二氧化碳 + 水 → 葡萄糖 + 氧气
Light energy, absorbed by chlorophyll in chloroplasts, is essential for this reaction to occur. The oxygen produced comes from the splitting of water molecules.
该反应需要叶绿体中的叶绿素吸收光能才能进行。释放的氧气来源于水分子的分解。
3. Aerobic Respiration Word Equation | 有氧呼吸单词方程式
Aerobic respiration takes place in the mitochondria of cells when oxygen is available. It releases energy for cellular activities.
有氧呼吸在氧气充足的条件下发生在线粒体内，为细胞活动提供能量。
Glucose + Oxygen → Carbon dioxide + Water (+ Energy)
葡萄糖 + 氧气 → 二氧化碳 + 水 (+ 能量)
This reaction is essentially the reverse of photosynthesis. Much of the energy released is stored in molecules of ATP for the cell to use.
该反应实质上是光合作用的逆反应。释放的大部分能量储存在ATP分子中，供细胞使用。
4. Anaerobic Respiration in Animals and Yeast | 动物及酵母的无氧呼吸
When oxygen is insufficient, cells switch to anaerobic respiration. Different organisms produce different end products.
当氧气不足时，细胞转为无氧呼吸，不同生物产生不同的终产物。
Anaerobic respiration in animals (muscle cells):
动物细胞（肌肉）的无氧呼吸：
Glucose → Lactic acid (+ Energy)
葡萄糖 → 乳酸 (+ 能量)
Lactic acid build-up causes muscle fatigue and cramps. It must later be broken down using oxygen (oxygen debt).
乳酸堆积会导致肌肉疲劳和抽筋，之后需要氧气将其分解（氧债）。
Anaerobic respiration in yeast (fermentation):
酵母的无氧呼吸（发酵）：
Glucose → Ethanol + Carbon dioxide (+ Energy)
葡萄糖 → 乙醇 + 二氧化碳 (+ 能量)
This reaction is used in baking and brewing. The carbon dioxide makes dough rise, while ethanol is the alcohol in drinks.
该反应用于烘焙和酿酒。二氧化碳使面团膨胀，乙醇则是饮料中的酒精。
5. Energy Transfer in Food Chains | 食物链中的能量传递
Energy enters most food chains via photosynthesis and is transferred from one trophic level to the next. However, a large portion is lost at each level, mainly as heat through respiration.
能量通过光合作用进入大多数食物链，并在营养级间传递。但是，每一级都有大量能量以呼吸散热等形式损耗。
Approximately 10% of the energy is passed on to the next level. The rest is used for life processes or lost as waste.
大约只有10%的能量传递到下一营养级，其余用于生命活动或以排泄物形式流失。
d efficiency = (Energy available to next level ÷ Energy available to previous level) × 100%
能量传递效率 = (下一级可利用能量 ÷ 上一级可利用能量) × 100%
This low efficiency explains why food chains rarely have more than four or five trophic levels.
低效率解释了为什么食物链通常只有四至五个营养级。
6. Biomass and Efficiency Calculations | 生物量与效率计算
Biomass is the mass of living material at a particular trophic level. It can be used to calculate the efficiency of biomass transfer.
生物量是指某一营养级上活生物体的质量，可用于计算生物量传递效率。
transfer = (Biomass transferred to next level ÷ Biomass available at previous level) × 100%
生物量传递效率 = (传递给下一级的生物量 ÷ 上一级可利用的生物量) × 100%
f grass biomass supports 100 kg of herbivore biomass, the efficiency is (100 ÷ 1000) × 100% = 10%.
例如，在典型食物链中，1000 kg的草生物量供养了100 kg的食草动物生物量，效率为 (100 ÷ 1000) × 100% = 10%。
7. Field Sampling and Population Estimation | 野外取样与种群估算
Ecologists often use sampling techniques to estimate population size without counting every individual. Two common methods are using quadrats and capture-mark-recapture.
生态学家常用取样法估算种群数量，无需逐个计数。两种常见方法是样方法和标记重捕法。
Quadrat method (for plants or slow-moving animals):
样方法（用于植物或移动缓慢的动物）：
ulation size = (Mean number of individuals per quadrat × Total area) ÷ Area of one quadrat
种群数量 = (每个样方平均个体数 × 总面积) ÷ 样方面积
Place several quadrats randomly, count individuals in each, and calculate the mean. Then multiply by the ratio of areas.
随机放置多个样方，计数每个样方内的个体数，求平均值，再乘以面积比例。
Capture-mark-recapture (for mobile animals):
标记重捕法（用于活动性强的动物）：
umber in first sample × Number in second sample) ÷ Number of marked individuals recaptured
种群估计值 = (第一次捕获并标记数 × 第二次捕获总数) ÷ 第二次捕获中标记个体数
This method assumes that marked individuals mix randomly with the population and that no births, deaths, or migrations occur between samples.
该方法假设标记个体与种群随机混合，且两次取样间无出生、死亡和迁移。
8. Enzyme Action – the Lock and Key Theorem | 酶作用——锁钥定理
Enzymes are biological catalysts that speed up reactions without being used up. The lock and key model explains enzyme specificity.
酶是生物催化剂，能加快反应而自身不被消耗。锁钥模型解释了酶的专一性。
In this model, the substrate fits into the enzyme's active site exactly like a key fits into a specific lock. Once bound, the enzyme–substrate complex forms, and the reaction can occur quickly.
该模型认为，底物与酶的活性位点精确契合，如同钥匙配锁。结合后形成酶-底物复合物，反应迅速发生。
Each enzyme works best at a specific temperature and pH. Deviations from these optimum conditions can denature the enzyme, changing the shape of the active site so the substrate no longer fits.
每种酶都有最适温度和pH。偏离最适条件可能导致酶变性，使活性位点形状改变，底物无法再契合。
9. Diffusion and Osmosis Principles | 扩散与渗透原理
Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, down the concentration gradient, until equilibrium is reached.
扩散是粒子从高浓度区域向低浓度区域的净移动，沿浓度梯度进行，直至达到平衡。
Osmosis is a special case of diffusion involving water molecules. Water moves across a partially permeable membrane from an area of high water concentration (dilute solution) to an area of low water concentration (concentrated solution).
渗透是扩散的一种特殊情况，涉及水分子。水通过半透膜从高水势（稀溶液）区域向低水势（浓溶液）区域移动。
Water potential gradient drives osmosis: High water potential → Low water potential
水势梯度驱动渗透：高水势 → 低水势
These passive processes require no cellular energy. They are vital for gas exchange, nutrient absorption, and water uptake in plants.
这些被动过程不消耗细胞能量，对气体交换、营养吸收和植物吸水至关重要。
10. Digestive System and Chemical Digestion Equations | 消化系统与化学消化方程式
Large food molecules must be broken down into smaller, soluble ones to be absorbed into the blood. Digestive enzymes catalyse these hydrolysis reactions.
食物大分子需要被分解为可溶的小分子才能被血液吸收。消化酶催化这些水解反应。
Carbohydrate digestion:
碳水化合物消化：
Starch → Maltose → Glucose
淀粉 → 麦芽糖 → 葡萄糖
Enzymes involved: amylase (in saliva and pancreatic juice) breaks starch into maltose; maltase (in small intestine) breaks maltose into glucose.
参与酶：唾液和胰液中的淀粉酶将淀粉分解为麦芽糖；小肠中的麦芽糖酶将麦芽糖分解为葡萄糖。
Protein digestion:
蛋白质消化：
Protein → Peptides → Amino acids
蛋白质 → 多肽 → 氨基酸
Proteases (e.g., pepsin in stomach, trypsin from pancreas) break proteins into peptides; peptidases complete the breakdown to amino acids.
蛋白酶（如胃中的胃蛋白酶、胰腺分泌的胰蛋白酶）将蛋白质分解为多肽；肽酶最终分解为氨基酸。
Lipid digestion:
脂类消化：
Lipids → Glycerol + Fatty acids
脂类 → 甘油 + 脂肪酸
Lipase enzymes, aided by bile salts that emulsify fats, break lipids into glycerol and fatty acids.
脂肪酶在胆盐乳化脂肪的协助下，将脂类分解为甘油和脂肪酸。
11. Inheritance and Punnett Square Probability | 遗传与旁氏表概率
Monohybrid inheritance follows patterns that can be predicted using Punnett squares, based on Mendel's law of segregation.
单基因遗传遵循孟德尔分离定律，可通过旁氏表预测。
Each parent contributes one allele for each gene. Dominant alleles mask recessive alleles. A Punnett square shows all possible combinations of gametes and the expected genotypic and phenotypic ratios.
每个亲本为每个基因提供一个等位基因。显性等位基因掩盖隐性等位基因。旁氏表列出所有可能的配子组合及预期的基因型与表现型比例。
| Male B (B) | Male b (b) | |
| Female B (B) | BB | Bb |
| Female b (b) | Bb | bb |
enotypic ratio is 1 BB : 2 Bb : 1 bb, and the phenotypic ratio is 3 dominant : 1 recessive.
两个杂合子 (Bb × Bb) 交配，预期基因型比例为 1 BB : 2 Bb : 1 bb，表现型比例为 3 显性 : 1 隐性。
12. Summary of Key Biochemical Symbols and Equivalences | 关键生化符号与等价关系汇总
Understanding the chemical symbols and molecular formulae used in biology is essential for interpreting equations and processes correctly.
掌握生物学中常用的化学符号和分子式是正确解读方程式与过程的基础。
| Symbol / Formula | Meaning | 中文含义 |
|---|---|---|
| CO₂ | Carbon dioxide | 二氧化碳 |
| H₂O | Water | 水 |
| C₆H₁₂O₆ | Glucose | 葡萄糖 |
| O₂ | Oxygen | 氧气 |
| C₂H₅OH | Ethanol | 乙醇 |
| ATP | Adenosine triphosphate | 三磷酸腺苷 |
Memorising these symbols will help you quickly translate word equations into chemical equations and deepen your understanding of metabolic pathways.
记住这些符号有助于你将单词方程式快速转化为化学方程式，并加深对代谢途径的理解。
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