📚 Year 10 SQA Biology: Formula & Theorem Quick-Reference Handbook | 苏格兰SQA生物：公式定理速查手册
In SQA Biology, mastering key formulas, equations and principles is essential for success. This quick-reference handbook gathers the most important quantitative relationships and theoretical statements you need for Year 10 – from photosynthesis and respiration to genetics, population sampling and energy flow. Keep it handy when revising.
在 SQA 生物课程中，掌握关键公式、方程式和原理是取得好成绩的基础。这本速查手册汇集了 Year 10 必须重点掌握的重要定量关系和理论表述，涵盖光合作用、呼吸作用、遗传学、种群抽样和能量流动等核心内容，适合随学随查、随查随记。
1. Photosynthesis Equation | 光合作用方程
Photosynthesis is the process by which green plants produce glucose and oxygen using light energy. The word equation summarises the reactants and products.
光合作用是绿色植物利用光能制造葡萄糖和氧气的过程。文字方程式总结了反应物和生成物。
Carbon dioxide + water → glucose + oxygen
(in the presence of light and chlorophyll)
二氧化碳 + 水 → 葡萄糖 + 氧气
(需要光和叶绿素)
molecules involved: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂. Glucose contains stored chemical energy.
平衡化学方程式显示了参与反应的确切分子数：6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂。葡萄糖中储存着化学能。
Photosynthesis takes place in chloroplasts and occurs in two main stages: the light-dependent reactions (which split water and produce ATP and oxygen) and the Calvin cycle (which fixes carbon dioxide into glucose).
光合作用在叶绿体中进行，分为两个主要阶段：光反应（分解水、产生 ATP 和氧气）和卡尔文循环（将二氧化碳固定为葡萄糖）。
2. Aerobic Respiration Equation | 有氧呼吸方程
Aerobic respiration releases energy from glucose in the presence of oxygen. It takes place in mitochondria and is summarised by the following equation.
有氧呼吸在氧气存在下从葡萄糖中释放能量，发生在线粒体中，可用以下方程式概括。
Glucose + oxygen → carbon dioxide + water (+ energy as ATP)
葡萄糖 + 氧气 → 二氧化碳 + 水 (+ 以 ATP 形式的能量)
piration produces up to 38 molecules of ATP per glucose molecule, making it far more efficient than anaerobic pathways.
平衡化学方程式为：C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O。有氧呼吸每分子葡萄糖最多可产生 38 个 ATP，效率远高于无氧途径。
ls, it produces ethanol and carbon dioxide: glucose → ethanol + carbon dioxide (+ energy).
在动物细胞中，无氧呼吸（发酵）产生乳酸：葡萄糖 → 乳酸 (+ 能量)。在植物和酵母细胞中，则产生乙醇和二氧化碳：葡萄糖 → 乙醇 + 二氧化碳 (+ 能量)。
3. Enzyme Activity & Factors | 酶活性与影响因素
Enzymes are biological catalysts that speed up reactions by lowering the activation energy. They are proteins with an active site specific to a particular substrate. The 'lock and key' model describes how the substrate fits into the active site to form an enzyme-substrate complex.
酶是生物催化剂，通过降低活化能来加速反应。它们是具有特定活性位点的蛋白质，活性位点与特定底物匹配。“锁钥”模型描述了底物如何嵌入活性位点形成酶-底物复合物。
The rate of enzyme-catalysed reactions is affected by temperature and pH. Each enzyme has an optimum temperature (around 37 °C for human enzymes) and an optimum pH (e.g. pepsin works best at pH 2, while amylase works best around pH 7).
酶促反应的速率受温度和 pH 影响。每种酶都有最适温度（人体酶约为 37 °C）和最适 pH（例如胃蛋白酶在 pH 2 时活性最高，而淀粉酶在 pH 7 左右活性最高）。
Graphs of enzyme activity show a characteristic bell-shaped curve as temperature rises – activity increases until the optimum, then declines sharply as the enzyme denatures and the active site changes shape irreversibly. pH graphs similarly show an optimum peak.
酶活性的曲线图随温度升高呈典型的钟形——活性上升直至最适点，然后急剧下降，因为酶变性且活性位点发生不可逆形变。pH 曲线同样显示最适峰值。
Substrate concentration also influences rate: the rate increases until all active sites become saturated, after which it plateaus.
底物浓度也会影响速率：速率上升直到所有活性位点都被占据，之后到达平台期。
4. Transport Across Cell Membranes | 跨膜运输方式
Substances move across cell membranes via diffusion, osmosis and active transport. Diffusion is the net movement of particles from an area of high concentration to an area of low concentration, down a concentration gradient. It is a passive process requiring no energy.
物质通过扩散、渗透和主动运输跨越细胞膜。扩散是粒子从高浓度区域向低浓度区域净移动的过程，顺浓度梯度进行，属于被动运输，不需要能量。
Osmosis is a special case of diffusion involving water molecules across a selectively permeable membrane from a region of higher water concentration (dilute solution) to a region of lower water concentration (concentrated solution).
渗透是扩散的一种特殊形式，指水分子透过选择性半透膜，从水势较高的区域（稀溶液）向水势较低的区域（浓溶液）移动。
Active transport moves substances against the concentration gradient – from low to high concentration – and requires energy in the form of ATP. Carrier proteins in the membrane change shape to transport specific ions or molecules.
主动运输逆浓度梯度移动物质——从低浓度到高浓度——并且需要 ATP 形式的能量。膜中的载体蛋白通过构象变化转运特定的离子或分子。
Factors affecting the rate of diffusion include concentration gradient, membrane surface area, membrane thickness, temperature and molecular size. For active transport, the availability of oxygen and glucose (for aerobic respiration) is crucial.
影响扩散速率的因素包括浓度梯度、膜表面积、膜厚度、温度和分子大小。对于主动运输，氧气和葡萄糖（用于有氧呼吸）的供应至关重要。
5. Magnification Formula | 放大倍数公式
When using a light microscope, you can calculate the size of a specimen using the magnification formula. This relationship is fundamental in cell biology practical work.
使用光学显微镜时，可以利用放大倍数公式计算标本的实际大小。这是细胞生物学实验中非常重要的基本关系。
Magnification = Image size ÷ Actual size
放大倍数 = 图像大小 ÷ 实际大小
al size. Always ensure that all measurements are in the same units (e.g. micrometres, millimetres). Convert units by remembering that 1 mm = 1000 µm.
若要计算实际大小，可变形为：实际大小 = 图像大小 ÷ 放大倍数。也可求图像大小：图像大小 = 放大倍数 × 实际大小。务必确保所有测量使用相同单位（如微米、毫米），并记住换算：1 mm = 1000 µm。
The triangle method is a useful memory aid: cover the quantity you want to find. For instance, covering Actual size leaves Image size ÷ Magnification.
“三角公式法”有助于记忆：盖住你要求的那一项，例如盖住实际大小，即得图像大小 ÷ 放大倍数。
6. Monohybrid Genetic Crosses | 单因子遗传杂交
Monohybrid crosses track the inheritance of a single characteristic determined by one gene with two alleles. Dominant alleles mask recessive alleles in heterozygous individuals. The genotype is the combination of alleles; the phenotype is the observable trait.
单因子杂交追踪由一个基因（具有两个等位基因）决定的单一性状的遗传。杂合子中，显性等位基因掩盖隐性等位基因。基因型是等位基因的组合，表现型是可观察的特征。
notypic ratio is 1 BB : 2 Bb : 1 bb, and the phenotypic ratio is 3 dominant : 1 recessive.
利用旁氏表可以预测子代比例。两个杂合亲本杂交（Bb × Bb），基因型比为 1 BB : 2 Bb : 1 bb，表现型比为 3 显性 : 1 隐性。
A test cross is used to determine an unknown genotype. Cross the individual showing the dominant phenotype with a homozygous recessive (bb) individual. If all offspring show the dominant trait, the unknown parent is homozygous dominant (BB). If a 1 : 1 ratio of dominant to recessive appears, the unknown parent is heterozygous (Bb).
测交用于确定未知基因型。将表现显性性状的个体与隐性纯合子 (bb) 杂交。若所有子代均表现显性，则未知亲本为显性纯合子 (BB)；若出现 1 : 1 的显隐性比例，则未知亲本为杂合子 (Bb)。
Typical SQA questions may also involve co-dominance or incomplete dominance, where the heterozygous phenotype is a blend of the two homozygous phenotypes. The ratios remain the same but the phenotype interpretation changes.
SQA 典型试题还会涉及共显性或不完全显性，此时杂合子表现型是两种纯合子表现型的混合，比例不变，但表现型解读不同。
7. DNA & the Central Dogma | DNA 与中心法则
DNA (deoxyribonucleic acid) is a double-stranded helix made of nucleotides. Each nucleotide contains a phosphate group, a deoxyribose sugar and a nitrogenous base (adenine, thymine, guanine, cytosine). Complementary base pairing states that adenine pairs with thymine (A–T) and guanine pairs with cytosine (G–C).
DNA（脱氧核糖核酸）是由核苷酸组成的双链螺旋。每个核苷酸含有一个磷酸基团、一个脱氧核糖和一个含氮碱基（腺嘌呤、胸腺嘧啶、鸟嘌呤、胞嘧啶）。碱基互补配对原则为：腺嘌呤与胸腺嘧啶配对 (A–T)，鸟嘌呤与胞嘧啶配对 (G–C)。
iption (taking place in the nucleus) copies a gene’s DNA into messenger RNA (mRNA). Translation (at the ribosome) decodes the mRNA sequence into a specific sequence of amino acids, forming a protein.
分子生物学的中心法则描述了遗传信息的流向：DNA → RNA → 蛋白质。转录（在细胞核中进行）将基因的 DNA 拷贝为信使 RNA (mRNA)。翻译（在核糖体上进行）将 mRNA 序列解码为特定的氨基酸序列，形成蛋白质。
A codon is a sequence of three mRNA bases that codes for one amino acid. The genetic code is universal and degenerate. SQA students should be able to interpret a snippet of a DNA-to-mRNA table.
一个密码子由三个 mRNA 碱基组成，编码一种氨基酸。遗传密码是通用且简并的。SQA 学生需能解读 DNA 到 mRNA 的对应表。
8. Energy Transfer & Ecological Pyramids | 能量传递与生态金字塔
Energy flows through ecosystems via food chains and webs. The efficiency of energy transfer between trophic levels can be calculated using the formula:
能量通过食物链和食物网在生态系统中流动。营养级间的能量传递效率可用下式计算：
Energy transfer efficiency (%) = (Energy in next trophic level ÷ Energy in previous trophic level) × 100%
能量传递效率 (%) = (下一营养级的能量 ÷ 上一营养级的能量) × 100%
Typically, only about 10% of energy is passed on; the rest is lost as heat, movement, respiration, uneaten matter and waste. This explains why food chains rarely exceed 4–5 trophic levels and why pyramids of energy are always upright.
通常大约只有 10% 的能量传递到下一级，其余以热、运动、呼吸、未食用部分和排泄物等形式散失。这解释了为什么食物链很少超过 4–5 个营养级，并且能量金字塔总是正向直立。
Pyramids of numbers show the number of organisms at each trophic level, but they can be inverted (e.g. one oak tree supporting many herbivores). Pyramids of biomass (dry mass) generally give a more accurate representation, though even these can be inverted in aquatic ecosystems during certain seasons. Only pyramids of energy are never inverted.
数量金字塔显示各营养级的生物个体数量，但可能出现倒置（如一棵橡树供养大量食草动物）。生物量（干重）金字塔通常更准确，但在水生生态系统某些季节也可能倒置。唯独能量金字塔永远不会倒置。
9. Population Estimation – Mark-Release-Recapture | 种群估计–标记重捕法
The Lincoln index (mark-release-recapture method) is used to estimate the population size of motile organisms. The formula is:
林肯指数（标记重捕法）用于估计移动生物的种群大小。公式为：
N = (M × C) ÷ R
种群数量 N = (M × C) ÷ R
- N = estimated total population
- M = number of individuals captured and marked in the first sample
- C = total number captured in the second sample
- R = number of marked individuals recaptured in the second sample
- N = 估计的总种群数量
- M = 第一次捕捉并标记的个体数
- C = 第二次捕捉的总个体数
- R = 第二次捕捉中带有标记的个体数
This method assumes that the marked individuals mix randomly with the rest of the population, no migration occurs, and marking does not affect survival or catchability. Violations of these assumptions reduce accuracy.
该方法假设标记个体与种群其他个体随机混合，没有迁入迁出，且标记不影响存活率或被捕捉几率。若假设不成立，估算精度会下降。
For sessile organisms, quadrat sampling is used instead. Percentage cover or scale of abundance is recorded, and total population can be estimated by scaling up the mean per quadrat to the whole habitat area.
对于固着生物，则采用样方法。记录样方内的覆盖百分比或丰度等级，再将每样方的平均值放大至整个栖息地面积，从而估算总种群数量。
10. Percentage Change & Data Handling | 百分比变化与数据处理
Experimental work in SQA Biology often requires you to calculate percentage change, mean values and handle raw data. The percentage change formula is essential for comparing results from different time points or treatments.
SQA 生物实验题常要求计算百分比变化、平均值并处理原始数据。百分比变化公式对于比较不同时间或处理的结果至关重要。
Percentage change (%) = [(Final value − Initial value) ÷ Initial value] × 100%
百分比变化 (%) = [(终值 − 初值) ÷ 初值] × 100%
A positive percentage change indicates an increase; a negative value indicates a decrease. When plotting graphs, remember to label axes with appropriate units and provide a descriptive title. Bar charts are used for discontinuous data, and line graphs for continuous data (e.g. time series). Best-fit lines should be drawn where a trend is apparent; avoid 'join-the-dots' unless instructed.
正百分比变化表示增加，负值表示减少。绘制图表时，务必给坐标轴标注适当单位并添加描述性标题。条形图适用于非连续性数据，折线图适用于连续性数据（如时间序列）。存在明显趋势时应绘制最佳拟合线，除非题目要求，否则不要“逐点连线”。
lues. The median is the middle value when data are ordered; the range = maximum − minimum.
还常需计算简单的统计量，如平均数、中位数和极差。平均数 = 所有数值之和 ÷ 数值个数。中位数是数据排序后的中间值；极差 = 最大值 − 最小值。
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