IGCSE AQA Biology: Cell Organelles – Key Exam Points | IGCSE AQA 生物：细胞器 考点精讲

📚 IGCSE AQA Biology: Cell Organelles – Key Exam Points | IGCSE AQA 生物：细胞器 考点精讲

Cell organelles are specialised structures within cells that perform distinct functions essential for life. For AQA IGCSE Biology, you need to know the structure and function of key organelles in animal and plant cells, and be able to compare them. Understanding these tiny ‘organs’ helps explain how cells carry out processes like respiration, protein synthesis, and photosynthesis. This revision guide covers the exam points you must master.

细胞器是细胞内具有特定功能的结构，对生命活动至关重要。在 AQA IGCSE 生物考试中，你需要掌握动植物细胞中关键细胞器的结构和功能，并能够进行比较。理解这些微小的“器官”有助于解释细胞如何完成呼吸作用、蛋白质合成和光合作用等过程。本复习指南涵盖必须掌握的考点。

1. Introduction to Cell Organelles | 细胞器简介

All living organisms are made of cells, the basic units of life. Within each eukaryotic cell, a variety of organelles are suspended in a jelly-like substance called cytoplasm. Organelles are either membrane-bound (e.g., nucleus, mitochondria) or non-membrane-bound (e.g., ribosomes). Their compartmentalisation allows different metabolic reactions to occur simultaneously without interference.

所有生物体都是由细胞构成的，细胞是生命的基本单位。在每个真核细胞内部，许多细胞器悬浮在一种称为细胞质的胶状物质中。细胞器有些有膜包被（如细胞核、线粒体），有些没有膜（如核糖体）。这种区室化使得不同的代谢反应能够同时进行而互不干扰。

In IGCSE, you will typically study organelles using a light microscope, although electron microscopes reveal more detail, such as the cristae of mitochondria. Be prepared to identify organelles in diagrams and explain their roles.

在 IGCSE 课程中，你通常使用光学显微镜研究细胞器，不过电子显微镜能显示更多细节，例如线粒体的嵴。要准备好从图中识别细胞器并解释其作用。

2. Nucleus – The Control Centre | 细胞核——控制中心

The nucleus is the largest organelle in many cells and is surrounded by a double membrane called the nuclear envelope, which contains pores. These pores allow substances like mRNA and ribosomes to move between the nucleus and the cytoplasm.

细胞核是许多细胞中最大的细胞器，由双层膜（核膜）包围，核膜上有核孔。这些核孔允许信使 RNA 和核糖体等物质在细胞核与细胞质之间进出。

Inside the nucleus, chromosomes are made of DNA. DNA carries the genetic instructions for making proteins. During cell division, chromosomes condense and become visible under a light microscope.

细胞核内有染色体，染色体由 DNA 组成。DNA 带有合成蛋白质的遗传指令。在细胞分裂过程中，染色体会浓缩并在光学显微镜下可见。

The nucleolus is a dense region within the nucleus where ribosomal RNA is synthesised and ribosome assembly begins. Exam tip: the nucleus controls all cellular activities because it contains the genetic material. It is found in both animal and plant cells, but not in mature red blood cells.

核仁是细胞核内的一个致密区域，是核糖体 RNA 合成和核糖体组装的起始场所。考试提示：细胞核控制所有细胞活动，因为它含有遗传物质。动植物细胞中都有细胞核，但成熟的红细胞没有细胞核。

3. Cytoplasm and Cell Membrane | 细胞质和细胞膜

The cytoplasm is a viscous fluid that fills the cell. It is mainly water with dissolved salts, enzymes, and organic molecules. Most metabolic reactions, including glycolysis, occur in the cytoplasm. The liquid component is sometimes called the cytosol.

细胞质是充满细胞的粘稠液体，主要成分是水，溶解有盐、酶和有机分子。大多数代谢反应，包括糖酵解，都在细胞质中进行。其液体部分有时称为胞质溶胶。

The cell membrane, also known as the plasma membrane, surrounds every cell. It is composed of a phospholipid bilayer with embedded proteins. Its function is to

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