Year 7 Cambridge Science: Unit Test Mock Paper Analysis | Year 7 剑桥科学：单元测试模拟卷解析

📚 Year 7 Cambridge Science: Unit Test Mock Paper Analysis | Year 7 剑桥科学：单元测试模拟卷解析

This article provides a detailed breakdown of a mock unit test designed for the Year 7 Cambridge Science curriculum. Each section corresponds to a common exam question, covering essential topics from biology, chemistry, and physics. By going through these worked solutions, you will reinforce key concepts, learn how to structure your answers, and avoid common pitfalls.

本文为针对Year 7剑桥科学课程的单元测试模拟卷提供详细解析。每一节对应一道常见的考试题目，涵盖生物、化学和物理的核心知识点。通过这些解题分析，你将巩固关键概念，学会如何组织答案，并避免常见错误。

1. Cell Structures and Functions | 细胞的结构与功能

Mock Question: The diagram shows a plant cell. Label the organelles A, B, C and D, and state one function for each. (8 marks)

模拟题： 下图为植物细胞。标注 A、B、C、D 四个细胞器，并分别说明它们的一项功能。（8分）

Structure A is the cell wall. It provides rigid support and protection for the cell.

结构A是细胞壁。它为细胞提供坚硬的支撑和保护。

Structure B is the nucleus. It contains the genetic material (DNA) and controls all cell activities.

结构B是细胞核。它含有遗传物质（DNA），并控制细胞的所有活动。

Structure C is the large permanent vacuole. It stores cell sap and helps maintain turgor pressure.

结构C是大永久液泡。它储存细胞液，并帮助维持膨压。

Structure D is a chloroplast. It contains chlorophyll and is the site of photosynthesis, producing glucose and oxygen.

结构D是叶绿体。它含有叶绿素，是光合作用的场所，产生葡萄糖和氧气。

A common mistake is to confuse the vacuole with the nucleus or to forget that animal cells lack a cell wall and chloroplasts.

一个常见错误是将液泡与细胞核混淆，或者忘记动物细胞没有细胞壁和叶绿体。

To compare plant and animal cells, remember:

要比较植物细胞与动物细胞，请记住：

Organelle	Plant Cell	Animal Cell
Cell wall	Present	Absent
Chloroplasts	Present (in leaves)	Absent
Large vacuole	Usually one large	Small or absent

Using this table in revision helps you answer comparative questions accurately.

复习时使用该表格有助于准确回答比较类问题。

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2. Particle Model of Matter | 物质的粒子模型

Mock Question: Explain what happens to the particles when a block of ice melts into liquid water. Use the particle model. (3 marks)

模拟题： 用粒子模型解释当一块冰融化成液态水时，粒子发生了什么变化。（3分）

In a solid, particles are closely packed in a regular pattern and vibrate in fixed positions.

在固体中，粒子紧密地排列成规则的图案，并在固定的位置上振动。

When heat energy is added, the particles gain kinetic energy and vibrate faster.

当加入热能时，粒子获得动能，振动得更快。

Eventually, the forces of attraction between particles weaken, allowing them to move past each other while still remaining close together, forming a liquid.

最终，粒子之间的吸引力减弱，使得粒子可以相互移动，但仍保持接近，从而形成液体。

The temperature at which this happens is called the melting point. A strong answer mentions energy, arrangement, and movement.

这个发生的温度叫做熔点。一个有力的答案会提到能量、排列和运动。

Many students forget to mention that in a liquid, particles are still touching but can flow. Linking energy transfer is crucial for full marks.

许多学生忘记提到，在液体中粒子仍然接触但可以流动。将能量转移联系起来是获得满分的关键。

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3. Separating Mixtures | 混合物的分离

Mock Question: A student has a mixture of sand, salt, and water. Describe how she can obtain pure dry salt from this mixture. Name the methods used. (4 marks)

模拟题： 一名学生有沙子、盐和水的混合物。描述她如何从该混合物中获得纯干燥的盐。说出所用方法的名称。（4分）

First, she should perform filtration to separate the insoluble sand from the salt solution.

首先，她应进行过滤，将不溶的沙子与盐溶液分离。

The mixture is poured through filter paper in a funnel; the sand residue stays in the filter paper, and the salt solution (filtrate) passes through.

将混合物倒入漏斗中的滤纸；沙子残渣留在滤纸上，而盐溶液（滤液）通过。

Next, she heats the salt solution to evaporate the water, leaving behind solid salt. This is evaporation, or she could use crystallisation for larger crystals.

接下来，她加热盐溶液以蒸发水，留下固体盐。这是蒸发，或者她可以使用结晶

Published by TutorHao | Year 7 Science Revision Series | aleveler.com

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