Year 7 CCEA Biology: Case Study Practice | 七年级 CCEA 生物：案例分析实战演练

📚 Year 7 CCEA Biology: Case Study Practice | 七年级 CCEA 生物：案例分析实战演练

In Year 7 CCEA Biology, case study questions are an excellent way to develop your understanding of key concepts in real-world contexts. This article will guide you through practical exercises, showing you how to analyse scenarios, apply scientific knowledge, and structure your answers effectively.

在七年级 CCEA 生物课程中，案例分析题是培养你在真实情境中理解关键概念的绝佳方式。本文将带你完成实战演练，教你如何分析情境、应用科学知识并有效组织答案。

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1. Introduction to Case Studies in Biology | 生物案例分析简介

Case studies in biology present a scenario or experiment, often accompanied by data, graphs, or observations. Your task is to interpret the information and use your biological knowledge to answer questions. For example, you might be given a description of a pond ecosystem and asked to explain feeding relationships or predict the effect of a change in population.

生物案例分析题会呈现一个情境或实验，通常附有数据、图表或观察结果。你的任务是解读信息并运用生物学知识回答问题。例如，题目可能描述一个池塘生态系统，要求解释捕食关系或预测某种群数量变化的影响。

These questions test not only recall but also application and analysis. You need to identify relevant facts, link them to the scenario, and provide reasoned explanations. Common topics include cells, photosynthesis, food chains, digestion, and habitat studies.

这类题目不仅考查记忆，还考查应用与分析能力。你需要识别相关事实，将其与情境联系起来，并给出合理的解释。常见主题包括细胞、光合作用、食物链、消化和栖息地研究。

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2. How to Approach a Case Study | 如何应对案例分析题

Follow a simple strategy: Read the case carefully, highlight key terms, and note any data. Ask yourself: What topic is this? What do I already know? Then read each question and plan your answer using scientific keywords. Always give evidence from the information provided.

遵照简单的策略：仔细阅读案例，划出关键术语，记下所有数据。问自己：这属于什么主题？我已经知道什么？然后阅读每个问题，用科学关键词规划答案。务必引用题目提供的信息作为证据。

For example, if a case mentions growth of algae in a lake, you might link it to nutrients (eutrophication) and explain how this reduces light for other plants. Use the PEEL structure: Point, Evidence, Explanation, Link.

例如，如果案例提及湖中藻类大量生长，你可以将其与营养物质（富营养化）联系起来，并解释这会如何减少其他植物的光照。使用PEEL结构：观点、证据、解释、联系。

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3. Case 1: Investigating Plant Cells | 案例一：探究植物细胞

Scenario: A student observed onion epidermis cells under a microscope, first using distilled water, then a concentrated salt solution. After the salt solution, the cell membrane pulled away from the cell wall. The student drew diagrams and recorded observations.

情境：一名学生在显微镜下观察洋葱表皮细胞，先使用蒸馏水，然后使用浓盐水。加入盐水后，细胞膜与细胞壁分离。学生画了示意图并记录了观察结果。

Questions asked: Why did the membrane pull away? What does this tell you about the cell wall and membrane? The answer is that water moved out of the cell by osmosis because the salt solution was hypertonic. The cell wall remains rigid, but the membrane shrinks.

问题：为什么细胞膜会分离？这说明了细胞壁和细胞膜的什么特性？答案是水因渗透作用从细胞内流出，因为盐水是高渗溶液。细胞壁保持坚硬，但细胞膜收缩。

This case tests osmosis, the selectively permeable membrane, and the structural role of the cell wall. Remember: water moves from a dilute to a concentrated solution through a partially permeable membrane.

该案例检测渗透作用、选择透过性膜以及细胞壁的结构功能。记住：水会通过部分透性膜从稀释溶液流向浓缩溶液。

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4. Case 2: Photosynthesis in Action | 案例二：光合作用实例

Scenario: An experiment measured the rate of photosynthesis of a pondweed by counting oxygen bubbles per minute at different distances from a lamp. The data showed: at 10 cm, 30 bubbles/min; at 20 cm, 18 bubbles/min; at 30 cm, 9 bubbles/min. The student then added sodium hydrogencarbonate to the water to provide extra CO₂, and the rate increased.

情境：一个实验通过计算不同距离光源下黑藻每分钟产生的氧气泡数量，测量光合作用速率。数据显示：距离10厘米，30气泡/分钟；20厘米，18气泡/分钟；30厘米，9气泡/分钟。学生随后在水中加入碳酸氢钠以提供额外CO₂，速率上升。

Questions may ask: Describe the relationship between distance and rate. Explain why the rate decreases as distance increases. Use the formula for light intensity:

问题可能问：描述距离与速率的关系。解释为什么速率随距离增加而下降。使用光照强度公式：

Light intensity ∝ 1 ÷ distance²

At double distance, intensity is ¼, so less energy is available for photosynthesis. Also, adding CO₂ increased the rate because CO₂ is a reactant. This shows that at low light, light is the limiting factor; when extra CO₂ is added, it can become a limiting factor too.

距离加倍时，光照强度为¼，因此用于光合作用的能量减少。此外，添加CO₂使速率提高，因为CO₂是反应物。这显示在低光强下，光是限制因素；当额外添加CO₂时，CO₂也能成为限制因素。

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5. Case 3: Food Chains and Energy Loss | 案例三：食物链与能量损失

Scenario: A marine food chain: phytoplankton → zooplankton → small fish → salmon. Numbers show: phytoplankton received 1,000,000 kJ of solar energy; zooplankton contain 100,000 kJ; small fish contain 10,000 kJ; salmon contain 1,000 kJ.

情境：一条海洋食物链：浮游植物 → 浮游动物 → 小鱼 → 鲑鱼。数据显示：浮游植物接收了1,000,000 kJ太阳能；浮游动物含有100,000 kJ；小鱼含有10,000 kJ；鲑鱼含有1,000 kJ。

Calculate the efficiency of energy transfer between two levels:

计算两个营养级之间的能量传递效率：

Efficiency = (energy in higher level ÷ energy in lower level) × 100% = (100,000 ÷ 1,000,000) × 100% = 10%

This 10% efficiency is typical because energy is lost as heat, in movement, and in uneaten parts. Explain why food chains rarely have more than 4–5 trophic levels: there is not enough energy to support another level. This case tests your ability to use numbers and understand energy pyramids.

这个10%的效率是典型的，因为能量会以热量、运动、未食用部分等形式损失。解释为什么食物链很少超过4-5个营养级：没有足够的能量支撑下一级。这个案例考查你运用数据以及理解能量金字塔的能力。

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6. Case 4: The Human Digestive System | 案例四：人体消化系统

Scenario: A patient has had their gall bladder removed. After the surgery, they find it difficult to digest fatty foods. A case study asks why, referring to the role of bile.

情境：一位病人切除了胆囊。手术后，他发现难以消化油腻食物。案例问为什么，需提及胆汁的作用。

The gall bladder stores bile, produced by the liver. Bile emulsifies fats, breaking large fat globules into smaller droplets, increasing surface area for lipase enzymes to work. Without bile, fat digestion is inefficient, leading to discomfort.

胆囊储存由肝脏产生的胆汁。胆汁乳化脂肪，将大脂肪球分解为小油滴，增加表面积使脂肪酶能更好地作用。没有胆汁，脂肪消化效率低下，导致不适。

This case links to the functions of the digestive organs and enzymes. You should also mention that lipase breaks down fats into fatty acids and glycerol, and that the small intestine absorbs these products.

这个案例联系到消化器官和酶的功能。你还应提及

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