📚 Formula and Theorem Quick Reference Handbook for Year 8 SQA Biology | Year 8 SQA 生物：公式定理速查手册
Welcome to your essential rapid revision guide for Year 8 SQA Biology. This handbook brings together the most important equations, laws, and models you will encounter in your course – from photosynthesis and respiration to genetics and ecology. Having these core facts at your fingertips will make revision more efficient and help you tackle exam questions with confidence.
欢迎使用 Year 8 SQA 生物学核心速查手册。本手册汇集了课程中最重要的方程式、定律和模型——从光合作用、呼吸作用到遗传学和生态学。把这些核心知识点熟记于心，能让你的复习更高效，为应对考试问题增添信心。
1. Photosynthesis Equation | 光合作用方程式
The overall word equation is: carbon dioxide + water → glucose + oxygen, in the presence of light and chlorophyll. The balanced chemical equation uses six molecules of each reactant: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂. Light energy is absorbed by chlorophyll and converted into chemical energy stored in glucose.
光合作用是绿色植物等利用光能将二氧化碳和水合成葡萄糖的过程。总文字方程式为：二氧化碳 + 水 → 葡萄糖 + 氧气，需光和叶绿素参与。配平的化学方程式为：6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂。光能被叶绿素吸收并转化为储存在葡萄糖中的化学能。
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
2. Aerobic Respiration Equation | 有氧呼吸方程式
: glucose + oxygen → carbon dioxide + water (+ energy released as ATP). The balanced chemical equation is exactly the reverse of photosynthesis: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O (+ energy). The energy is used for cell activities such as growth, repair, and movement.
有氧呼吸在氧气充足时于细胞的线粒体中进行，高效地从葡萄糖中释放能量。文字方程式：葡萄糖 + 氧气 → 二氧化碳 + 水（+ 以 ATP 形式释放的能量）。配平的化学方程式恰好是光合作用的逆过程：C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O（+ 能量）。释放的能量用于细胞活动，如生长、修复和运动。
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O (+ energy)
3. Anaerobic Respiration Equations | 无氧呼吸方程式
ic acid: glucose → lactic acid (+ energy). The chemical shorthand is C₆H₁₂O₆ → 2C₃H₆O₃. In yeast and some plants, anaerobic respiration produces ethanol and carbon dioxide instead: glucose → ethanol + carbon dioxide (+ energy), written as C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂. Anaerobic respiration generates far less ATP than aerobic respiration.
当氧气不足时，细胞可通过无氧呼吸释放少量能量。在人体肌肉中，葡萄糖转化为乳酸：葡萄糖 → 乳酸（+ 能量），化学简式为 C₆H₁₂O₆ → 2C₃H₆O₃。在酵母和部分植物中，无氧呼吸则产生乙醇和二氧化碳：葡萄糖 → 乙醇 + 二氧化碳（+ 能量），即 C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂。无氧呼吸产生的 ATP 远少于有氧呼吸。
Muscle cells: C₆H₁₂O₆ → 2C₃H₆O₃ (+ energy)
Yeast: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ (+ energy)
4. Lock-and-Key Model of Enzyme Action | 酶作用的锁钥模型
Enzymes are biological catalysts that speed up reactions by lowering the activation energy. The lock-and-key model states that each enzyme has an active site with a specific three‑dimensional shape. Only a substrate with a complementary shape can bind to the active site, forming an enzyme–substrate complex. This high specificity explains why an enzyme that digests starch cannot digest proteins, and why changes in temperature or pH (which alter the shape of the active site) can denature the enzyme.
酶是生物催化剂，通过降低活化能来加快反应。锁钥模型认为，每种酶都有一个具有特定三维形状的活性位点。只有形状互补的底物才能与该活性位点结合，形成酶–底物复合物。这种高度专一性解释了为何消化淀粉的酶不能消化蛋白质，以及温度或 pH 变化（改变活性位点形状）何以使酶变性。
- Active site = lock; Substrate = key.
- 活性位点 = 锁；底物 = 钥匙。
- The model helps predict how competitive inhibitors work.
- 该模型有助于理解竞争性抑制剂的作用机理。
5. Mendel's Law of Segregation | 孟德尔分离定律
Gregor Mendel's law of segregation states that every individual possesses two alleles for each gene, one inherited from each parent. During gamete formation (meiosis), these two alleles separate so that each gamete carries only one allele for the trait. When gametes fuse at fertilisation, the offspring receives one allele from each parent, restoring the pair. This law is the foundation of monohybrid inheritance and explains the classic 3:1 phenotypic ratio observed in the F2 generation of a cross between two heterozygous parents.
孟德尔分离定律指出，每个个体针对每个基因拥有两个等位基因，分别来自父母。在配子形成（减数分裂）时，这两个等位基因彼此分离，因此每个配子只携带该性状的一个等位基因。受精时，后代从双亲各获得一个等位基因，重新组成一对。该定律是单基因遗传的基础，也解释了杂合子亲本杂交 F2 代典型的 3:1 表型比。
Aa × Aa → 1 AA : 2 Aa : 1 aa (genotypic ratio)
Phenotypic ratio = 3 dominant : 1 recessive
6. Punnett Square and Genetic Probability | 庞纳特方格与遗传概率
types and phenotypes of offspring from a genetic cross. The alleles carried by each parent' ygous individuals (Aa × Aa), the probability of the dominant phenotype appearing is 3/4 (75%), and the recessive phenotype is 1/4 (25%). This tool also makes it easy to visualise Mendel's law of segregation in action.
庞纳特方格是预测杂交后代基因型和表型的示意图。将亲本配子携带的等位基因写在方格的顶部和侧边，方格内则展示所有可能的等位基因组合。就杂合子个体间的单基因杂交（Aa × Aa）而言，显性表型出现的概率为 3/4（75%），隐性表型为 1/4（25%）。该工具还能直观地呈现孟德尔分离定律的作用过程。
| A | a | |
| A | AA | Aa |
| a | Aa | aa |
Dominant probability = ¾, Recessive probability = ¼
7. Energy Transfer in Food Chains (10% Rule) | 食物链中的能量传递（10%规则）
In an ecosystem, energy passes from one trophic level to the next through feeding. On average, only about 10% of the energy stored in one trophic level is transferred to the level above. Most of the remaining 90% is lost through metabolic processes, heat, movement, and undigested materials. This low transfer efficiency explains why food chains rarely have more than four or five trophic levels and why producers (green plants) always form the base of the pyramid of biomass.
在生态系统中，能量通过捕食从一个营养级传递至下一营养级。平均而言，某一营养级储存的能量中只有约 10% 传递到上一级，其余约 90% 通过代谢、产热、运动及未消化物质等途径散失。如此低的传递效率解释了为何食物链很少超过四至五个营养级，也说明生产者（绿色植物）为何总是占据生物量金字塔的基底。
Energy available at next level ≈ 10% of previous level's energy
8. Magnification Formula | 放大倍数公式
ctive lens. This simple formula is essential for estimating the size of cells and other microscopic structures. When you combine a ×10 eyepiece with a ×40 objective, the specimen is magnified 400 times (×400). To find the actual size of an object, rearrange the formula: actual size = image size ÷ total magnification.
光学显微镜的总放大倍数等于目镜放大倍数乘以物镜放大倍数。这个简单的公式对于估算细胞和其他显微结构的大小至关重要。当使用 ×10 目镜和 ×40 物镜时，标本被放大 400 倍（×400）。要计算物体的实际尺寸，可转换公式：实际尺寸 = 图像尺寸 ÷ 总放大倍数。
Total Magnification = Eyepiece Magnification × Objective Magnification
Actual Size = Image Size ÷ Total Magnification
9. Diffusion and Surface Area : Volume Ratio | 扩散与表面积体积比
icles from a region of higher concentration to a region of lower concentration. The rate of diffusion is influenced by three main factors: the surface area of the exchange membrane, the concentration gradient, and the thickness of the membrane. This relationship is often summarised as: Rate ∝ rence) ÷ Diffusion Distance. Living organisms maximise diffusion by having specialised exchange surfaces with a large surface area and a thin barrier, such as the alveoli in the lungs or the flat shape of leaves.
扩散是指粒子从高浓度区域向低浓度区域的净移动。扩散速率受三个主要因素影响：交换膜的表面积、浓度梯度以及膜的厚度。这一关系常概括为：扩散速率 ∝（表面积 × 浓度差）÷ 扩散距离。生物体通过拥有表面积大、屏障薄的专门交换表面来最大化扩散效率，例如肺部的肺泡和叶片的扁平形态。
Diffusion Rate ∝ (Surface Area × Concentration Difference) / Membrane Thickness
10. Water Potential and Osmosis in Cells | 水势与细胞渗透作用
Osmosis is the diffusion of water molecules across a partially permeable membrane from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution). In animal cells, if the external solution has a higher water potential (hypotonic), water enters the cell and may cause it to burst. In plant cells, the cell wall prevents bursting; the cell becomes turgid. In a concentrated (hypertonic) solution, plant cells lose water and undergo plasmolysis, while animal cells shrink.
渗透作用是水分子穿过半透膜从高水势区域（稀溶液）向低水势区域（浓溶液）的扩散。在动物细胞中，若外部溶液水势较高（低渗），水进入细胞可能导致其破裂。植物细胞中，细胞壁可防止破裂，细胞变为紧张状态。在高浓度（高渗）溶液中，植物细胞失水并发生质壁分离，而动物细胞则皱缩。
- Higher water potential → lower water potential movement.
- 水从高水势向低水势移动。
- Hypotonic = less concentrated than cell; Hypertonic = more concentrated.
- 低渗 = 浓度低于细胞内液；高渗 = 浓度高于细胞内液。
Published by TutorHao | Biology Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图