Cell Organelles for GCSE Edexcel Biology | GCSE Edexcel 生物：细胞器 考点精讲

📚 Cell Organelles for GCSE Edexcel Biology | GCSE Edexcel 生物：细胞器 考点精讲

All organisms are made of cells, and understanding the tiny structures inside them—organelles—is key to GCSE Biology. Each organelle has a specific function that contributes to the cell’s overall activity. In the Edexcel specification, you are expected to identify and describe the roles of organelles in animal, plant and bacterial cells, and to compare these cell types.

所有生物都由细胞构成，理解细胞内部的微小结构——细胞器——是 GCSE 生物学的关键。每种细胞器都有特定的功能，共同维持细胞的活动。在 Edexcel 考纲中，你需要识别并描述动物、植物和细菌细胞中细胞器的作用，并对这些细胞类型进行比较。

1. Nucleus | 细胞核

The nucleus is often referred to as the ‘control centre’ of the cell. It is surrounded by a double membrane called the nuclear envelope, which contains pores to allow molecules to move in and out. Inside the nucleus are chromosomes made of DNA, which carry the genetic instructions for making proteins and controlling cell activities. The nucleus is present in all plant and animal cells, but bacterial cells do not have a true nucleus—they have a single circular strand of DNA that lies free in the cytoplasm.

细胞核通常被称为细胞的 “控制中心”。它被双层膜（核膜）所包围，核膜上有核孔，允许分子进出。细胞核内有由 DNA 组成的染色体，携带着合成蛋白质和控制细胞活动的遗传指令。细胞核存在于所有植物和动物细胞中，但细菌细胞没有真正的细胞核——它们有一条环状的 DNA 链，游离在细胞质中。

2. Cytoplasm | 细胞质

Cytoplasm is the jelly-like substance that fills the cell and surrounds the organelles. It is mainly composed of water, salts and organic molecules. Many metabolic reactions, such as the initial stages of respiration and protein synthesis, take place in the cytoplasm. In bacterial cells, the cytoplasm also contains plasmids—small rings of DNA that can be transferred between bacteria.

细胞质是充满细胞并包围细胞器的果冻状物质。它主要由水、盐和有机分子组成。许多代谢反应，如呼吸作用的初始阶段和蛋白质合成，都在细胞质中进行。在细菌细胞中，细胞质还包含质粒——可以在细菌之间转移的小型环状 DNA。

3. Cell Membrane | 细胞膜

The cell membrane, also known as the plasma membrane, forms the outer boundary of animal cells and lies just inside the cell wall in plant and bacterial cells. It is composed of a phospholipid bilayer with embedded proteins, giving it a selectively permeable nature. This means it controls the movement of substances such as glucose, ions and waste products into and out of the cell. In your exam, you should be able to describe how the cell membrane allows diffusion, osmosis and active transport.

细胞膜，也称为质膜，形成了动物细胞的外边界，在植物和细菌细胞中位于细胞壁的内侧。它由磷脂双分子层和嵌入的蛋白质组成，使其具有选择透过性。这意味着它控制着诸如葡萄糖、离子和废物等物质进出细胞。在考试中，你需要能够描述细胞膜如何允许扩散、渗透和主动运输。

4. Mitochondria | 线粒体

Mitochondria are membrane-bound organelles that carry out aerobic respiration. They have a double membrane, with the inner membrane folded into cristae to increase the surface area for reactions. Mitochondria use oxygen to break down glucose and release energy in the form of ATP, which is used to power cellular processes. The overall word equation for aerobic respiration can be summarised as:

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

Muscle cells and sperm cells contain large numbers of mitochondria because they require a lot of energy. Bacteria do not have mitochondria; instead, respiration occurs across their cell membrane.

线粒体是进行有氧呼吸的膜包裹细胞器。它们具有双层膜，内膜向内折叠形成嵴，以增加反应的表面积。线粒体利用氧气分解葡萄糖，释放 ATP 形式的能量，用于驱动细胞活动。有氧呼吸的总文字方程式可以归纳为上面的化学方程式。肌肉细胞和精子细胞含有大量的线粒体，因为它们需要大量能量。细菌没有线粒体；相反，它们的呼吸作用在细胞膜上进行。

5. Ribosomes | 核糖体

Ribosomes are tiny organelles that are the sites of protein synthesis (translation). They are made of ribosomal RNA and proteins and can be found free in the cytoplasm or attached to the rough endoplasmic reticulum. Ribosomes read the genetic code carried by messenger RNA and link amino acids together to form polypeptide chains. Ribosomes are present in all types of cells—animal, plant and bacterial—reflecting the universal need for proteins.

核糖体是蛋白质合成（翻译）的场所，是一种微小的细胞器。它们由核糖体 RNA 和蛋白质组成，可以游离在细胞质中，或附着在粗面内质网上。核糖体读取信使 RNA 携带的遗传密码，并将氨基酸连接成多肽链。核糖体存在于所有类型的细胞中——动物、植物和细菌——这反映了对蛋白质的普遍需求。

6. Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER) | 粗面内质网与滑面内质网

The endoplasmic reticulum (ER) is a network of membrane-bound channels throughout the cytoplasm. Rough ER has ribosomes attached to its surface; it processes and transports proteins made by the ribosomes to the Golgi apparatus. Smooth ER has no ribosomes and is involved in the synthesis and transport of lipids, including steroids, and in detoxification. Both types of ER are found in animal and plant cells but are absent in bacteria.

内质网（ER）是贯穿细胞质的膜包被通道网络。粗面内质网表面附着核糖体；它处理并运输核糖体合成的蛋白质到高尔基体。滑面内质网没有核糖体，参与脂质（包括类固醇）的合成和运输以及解毒作用。两种内质网都存在于动物和植物细胞

Published by TutorHao | GCSE Biology Revision Series | aleveler.com

更多咨询请联系16621398022（同微信）