📚 Year 10 OCR Biology: Quick Reference of Formulas & Key Principles | Year 10 OCR 生物：公式定理速查手册
This handbook collects all the essential formulas, equations, and quantitative principles you need to confidently tackle Year 10 OCR GCSE Biology. From magnification and enzyme kinetics to sampling techniques and energy transfers, each section presents the key relationship first in English, then in Chinese, followed by a practical explanation and worked examples where appropriate. Keep it close for exam revision.
本手册汇集了 Year 10 OCR GCSE 生物学所有必备的公式、方程式和定量原理。从放大倍数与酶动力学，到取样技术和能量传递，每个部分先用英文给出关键关系，再用中文加以说明，并提供实际解释与计算示例。考前复习时请随时翻阅。
1. Magnification Formula | 放大倍数公式
The magnification of a biological drawing or microscope image is calculated using the relationship between the size of the image and the actual size of the specimen. All measurements must be in the same unit.
生物绘图或显微镜图像的放大倍数由图像尺寸与标本实际尺寸之间的关系计算。所有测量必须使用相同单位。
Magnification = Image size ÷ Actual size
放大倍数 = 图像尺寸 ÷ 实际尺寸
To find the actual size, rearrange to: Actual size = Image size ÷ Magnification . If the image size is measured in millimetres and the actual size is in micrometres, always convert to the same unit first (1 mm = 1000 µm).
求实际尺寸可使用变形公式：实际尺寸 = 图像尺寸 ÷ 放大倍数。若图像尺寸以毫米为单位，实际尺寸以微米为单位，务必先换算为同一单位（1 毫米 = 1000 微米）。
ell image is 30 mm wide and its actual width is 0.06 mm, magnification = 30 ÷ 0.06 = ×500.
请注意，放大倍数没有单位，它只是一个比值。例如，若细胞图像宽 30 毫米，实际宽 0.06 毫米，则放大倍数 = 30 ÷ 0.06 = ×500。
2. Rate of Reaction | 反应速率
In enzyme-controlled reactions, the rate measures how quickly a product is formed or a substrate is used up over a given time. It can be measured as the quantity of product formed per unit time.
在酶控制的反应中，速率衡量在给定时间内产物生成或底物消耗的快慢。它可以表示为每单位时间生成产物的数量。
Rate = Change in quantity (product or substrate) ÷ Time taken
速率 = 量的变化（产物或底物） ÷ 所用时间
Common experiments use the volume of gas evolved (e.g., O₂ from catalase breaking down H₂O₂) or the disappearance of a colour (e.g., starch-iodine). The units might be cm³/s or absorbance change per minute. The initial rate is often the steepest part of the graph.
常见实验有测量产生气体的体积（如过氧化氢酶分解 H₂O₂ 释放 O₂）或观察颜色消失（如淀粉-碘反应）。单位可以是 cm³/s 或每分钟吸光度变化。初始速率通常是曲线最陡峭的部分。
3. Photosynthesis Word and Symbol Equations | 光合作用的文字方程式与符号方程式
Photosynthesis is the process by which green plants and algae use light energy to convert carbon dioxide and water into glucose and oxygen.
光合作用是绿色植物和藻类利用光能把二氧化碳和水转化为葡萄糖和氧气的过程。
carbon dioxide + water → glucose + oxygen
二氧化碳 + 水 → 葡萄糖 + 氧气
The balanced chemical equation is: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
配平的化学方程式为：6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
Light energy, absorbed by chlorophyll, is essential and is written above the arrow. The glucose produced can be used immediately for respiration, stored as insoluble starch, or used to make other organic molecules such as cellulose, amino acids and lipids.
光能由叶绿素吸收，是必需条件，通常写在箭头上方。产生的葡萄糖可立即用于呼吸作用、转化为不溶性淀粉储存，或用于制造纤维素、氨基酸和脂质等其他有机物。
4. Respiration Equations | 呼吸作用方程式
Respiration is an exothermic reaction that releases energy from glucose. Cells use this energy for movement, active transport and building larger molecules. There are two main types – aerobic and anaerobic.
呼吸作用是释放葡萄糖中能量的放热反应。细胞利用这些能量进行运动、主动运输和合成大分子。呼吸作用主要分为有氧呼吸和无氧呼吸两类。
Aerobic: glucose + oxygen → carbon dioxide + water (+ energy)
有氧呼吸：葡萄糖 + 氧气 → 二氧化碳 + 水（+ 能量）
Balanced symbol equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
配平符号方程式：C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
Anaerobic respiration in animal cells produces lactic acid: glucose → lactic acid (+ energy). In plant and yeast cells, anaerobic respiration produces ethanol and carbon dioxide: glucose → ethanol + carbon dioxide (+ energy). This is also called fermentation.
动物细胞的无氧呼吸产生乳酸：葡萄糖 → 乳酸（+ 能量）。在植物和酵母细胞中，无氧呼吸产生乙醇和二氧化碳：葡萄糖 → 乙醇 + 二氧化碳（+ 能量），也称为发酵。
5. Cardiac Output Formula | 心输出量公式
The cardiac output is the volume of blood pumped by the heart per minute. It depends on the heart rate and the stroke volume.
心输出量是心脏每分钟泵出的血液体积，它取决于心率和每搏输出量。
Cardiac output = Heart rate × Stroke volume
心输出量 = 心率 × 每搏输出量
nute or litres per minute. For an average resting adult, heart rate ≈ 70 bpm, stroke volume ≈ 70 ml, so cardiac output ≈ 4900 ml/min (4.9 L/min). During exercise, both heart rate and stroke volume can increase dramatically.
心率以每分钟心跳次数（bpm）为单位，每搏输出量以毫升（ml）每搏为单位，因此心输出量通常用 ml/min 或 L/min 表示。一般静息成年人，心率约 70 bpm，每搏输出量约 70 ml，故心输出量约为 4900 ml/min（4.9 L/min）。运动时，心率和每搏输出量均可显著升高。
6. Breathing Rate and Ventilation | 呼吸频率与肺通气量
Pulmonary ventilation is the total volume of air moved in and out of the lungs per minute. It can be calculated from the breathing rate and tidal volume.
肺通气量是每分钟进出肺的空气总体积，可由呼吸频率和潮气量计算得到。
Ventilation rate = Breathing rate × Tidal volume
肺通气量 = 呼吸频率 × 潮气量
Breathing rate is the number of breaths per minute. Tidal volume is the volume of air moved in and out during one normal breath (usually about 0.5 L in adults). The unit for ventilation is litres per minute. This is not the same as cardiac output; do not confuse them.
呼吸频率是每分钟呼吸次数。潮气量是一次正常呼吸吸入或呼出的空气体积（成人通常约 0.5 L）。肺通气量的单位是升每分钟。注意不要与心输出量混淆。
7. Energy Transfer Efficiency (Food Chains) | 能量传递效率（食物链）
Only a fraction of the energy stored in one trophic level is transferred to the next. This efficiency can be calculated to understand productivity.
储存在一个营养级中的能量，只有一小部分能传递到下一个营养级。通过计算传递效率可了解生产力。
Efficiency = (Energy available to next level ÷ Energy available to previous level) × 100%
效率 = （传递给下一级的能量 ÷ 上一级可用的能量）× 100%
Alternatively, using biomass: Efficiency = (Biomass in higher trophic level ÷ Biomass in lower trophic level) × 100%. Most energy transfers are about 10% efficient. The rest is lost through respiration, undigested wastes, movement and heat.
也可使用生物量计算：效率 = （较高营养级的生物量 ÷ 较低营养级的生物量）× 100%。多数能量传递效率约为 10%。其余能量通过呼吸作用、未消化废物、运动和散热等形式散失。
When drawing pyramids of biomass, always use dry mass per g/m² or kg/m² to standardise measurements.
绘制生物量金字塔时，务必使用干重（g/m² 或 kg/m²）来标准化测量。
8. Quadrat Sampling and Population Estimation | 样方法种群数量估算
To estimate the population size of slow-moving or non-moving organisms in a habitat, ecologists use random sampling with quadrats and apply a scaling formula.
为了估算栖息地中行动缓慢或不移动的生物种群数量，生态学家使用样方随机取样并套用比例公式。
pulation estimate = (Mean count per quadrat ÷ Area of one quadrat) × Total area of habitat
种群总数估算值 = （每样方平均计数 ÷ 一个样方面积）× 栖息地总面积
n measure the area of the quadrat (e.g., 0.5 m × 0.5 m = 0.25 m²) and the total area of the sampling site. Multiply to scale up.
首先随机放置样方（如使用随机数坐标），计数每个样方内的生物数量，求平均值。再测量样方面积（例如 0.5 m × 0.5 m = 0.25 m²）和整个调查区域的总面积，然后按比例放大。
ore quadrats improves accuracy. Use mean × total area / quadrat area for a quick estimate.
该方法假设生物分布均匀；放置更多样方可提高准确性。快速估算可用平均数量 × 总面积 ÷ 样方面积。
9. Probability in Genetics (Punnett Square) | 遗传概率（庞纳特方格）
Genetic inheritance follows rules of probability. The chances of an offspring inheriting a particular genotype can be predicted using a Punnett square, provided we know the parental genotypes.
遗传遵循概率规则。只要知道亲本基因型，就可以用庞纳特方格预测后代获得特定基因型的概率。
For a monohybrid cross, probability of each genotype is: Number of desired outcomes ÷ Total number of possible outcomes. These ratios are often expressed as 3:1, 1:2:1 etc., or as percentages/fractions.
单基因杂交中，每种基因型的概率 = 期望结果数 ÷ 所有可能结果总数。这些比例通常表示为 3:1、1:2:1 等，也可写成分数或百分数。
4, Aa 1/2, aa 1/4. If a condition is recessive, the probability of affected offspring is 1/4 or 25%.
例如，杂合子杂交（Aa × Aa）得到：AA 1/4，Aa 1/2，aa 1/4。如果某种性状为隐性，则患病后代的概率为 1/4 或 25%。
When two genes are on separate chromosomes, use the rule of multiplication: of : Probability of two independent events both happening = Probability of event 1 × Probability of event 2.
当两个基因位于不同染色体上时，使用乘法法则：两个独立事件同时发生的概率 = 事件 1 的概率 × 事件 2 的概率。
10. Q10 Coefficient for Enzyme-Controlled Reactions | 酶控反应的 Q10 温度系数
The Q10 coefficient measures how much the rate of a reaction increases with a 10°C rise in temperature. It is commonly used to describe enzyme activity within the optimum range.
Q10 系数衡量温度每升高 10°C 反应速率增加的倍数，常用于描述酶在最适温度范围内的活性变化。
Q10 = Rate at (T + 10)°C ÷ Rate at T °C
Q10 = （T+10）°C 时的速率 ÷ T °C 时的速率
Most enzyme-controlled reactions have a Q10 of around 2, meaning the rate doubles for each 10°C rise up to the optimum. Above the optimum, the enzyme denatures and the rate drops sharply, so Q10 is only meaningful below the denaturation temperature.
大多数酶控反应的 Q10 值约为 2，即温度每升高 10°C 速率加倍，直至达到最适温度。超过最适温度后酶会变性，速率骤降，因此 Q10 仅在变性温度以下才有意义。
11. Osmosis and Water Potential | 渗透作用与水势
Osmosis is the net movement of water molecules from a region of higher water potential to a region of lower water potential across a partially permeable membrane. Water potential is measured in kilopascals (kPa) and pure water has a water potential of 0 kPa.
渗透作用是水分子通过部分透性膜从较高水势区域向较低水势区域的净移动。水势以千帕（kPa）为单位，纯水的水势为 0 kPa。
The direction of water movement can be predicted by comparing the water potentials of two solutions. Water moves toward the more negative water potential (more concentrated solute). The formula for calculating the percentage change in mass is often used in osmosis experiments:
通过比较两种溶液的水势可预测水流动方向。水总是流向水势更负（溶质浓度更高）的一侧。渗透实验中常计算质量变化百分比：
% Change in mass = (Final mass − Initial mass) ÷ Initial mass × 100%
质量变化百分比 = （最终质量 − 初始质量） ÷ 初始质量 × 100%
A positive value means the tissue gained water (hypotonic external solution), a negative value means it lost water (hypertonic external solution).
正值表示组织吸水（外液为低渗），负值表示组织失水（外液为高渗）。
12. Microscope Calibration and Measurement | 显微镜校准与测量
To measure cells under the microscope, you must calibrate the eyepiece graticule using a stage micrometer. This allows you to convert graticule units (arbitrary units) into real measurements.
要在显微镜下测量细胞，必须使用载台测微尺校准目镜测微尺，从而将测微尺的任意单位转换为真实长度单位。
Step 1: Line up the graticule scale with the stage micrometer. The stage micrometer has precise divisions, usually 0.01 mm (10 µm) each.
第一步：将目镜测微尺的刻度与载台测微尺对齐。载台测微尺有精确刻度，通常每格为 0.01 mm（10 µm）。
Step 2: Count how many graticule divisions correspond to a known number of stage divisions.
(Number of stage divisions × Length of one stage division) ÷ Number of graticule divisions
第二步：计数一定数量的载台测微尺刻度对应多少目镜测微尺刻度。
校准值 = （载台格数 × 每格长度） ÷ 目镜格数
For example, if 40 graticule divisions cover 10 stage divisions (0.1 mm = 100 µm), then 1 graticule division = 100 µm ÷ 40 = 2.5 µm. Measure your specimen and multiply by the calibration value.
例如，若 40 个目镜格等于 10 个载台格（0.1 mm = 100 µm），则 1 个目镜格 = 100 µm ÷ 40 = 2.5 µm。测量标本后乘以校准值即可得到真实尺寸。
Always recalibrate if the magnification is changed.
如果更换放大倍数，必须重新校准。
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