Name: cell compartments in eukaryotes
Uploaded: 2020-11-23T11:47:33.000Z
Duration: 1 min 46 s
Channel: JoVE

真核细胞
 
 含有许多细胞区室
 
 膜结合细胞器只允许
 
 特定功能在微环境中
 
 发挥作用
 
 保护其不受细胞质内环境
 
 和细胞外环境的影响
 
 例如 细胞核要求控制条件下
 
 使其内部的基因进行精准调节
 
 因此 它被双层膜包围
 
 细胞核被膜带有核孔
 
 核孔可以控制分子的进出 例如信使核糖核酸
 
 此外 一些蛋白质需要氧化环境
 
 且必须与还原性的细胞质体隔离
 
 因此 核糖体在内质网中
 
 生产这些蛋白质
 
 同时在内质网中这些蛋白质可以进行关键性的修饰
 
 在其到达最终目的地前 后续的反应甚至在
 
 被称为囊泡的微小化学环境中发生
 
 其它的细胞器 例如过氧化物酶体
 
 保护自己不受他们有害的副产品的影响
 
 如过氧化氢
 
 会隔绝那些能将有毒的混合物
 
 转化成 例如水这样的无害分子
 
 相似地 溶酶体能分离酶
 
 但原因不同
 
 溶酶体是为了保障消化反应的进行
 
 而消化反应需要比细胞质PH值低得多的环境
 
 线粒体内也含有酸性物质
 
 他们在线粒体的双层膜内协助产生能量
 
 总之 真核细胞区室支持
 
 在没有隔离时会互相排斥的反应
 
 能够同时发生

Gabaldón、Toni 和 Alexandros A. Pittis。"真核生物代谢亚细胞区室化的起源和进化。"生物奇米 119（2015 年 12 月）:262-68。[<a href="https://doi.org/10.1016/j.biochi.2015.03.021" target="__blank">来源</a>]

真核生物区室化

真核细胞的一个显著特征是，它们含有膜结合的细胞器，如细胞核和线粒体，具有特定的功能。由于生物膜只能渗透到少量的物质，细胞器周围的膜创造了一个内部条件可控的区室。这些微环境通常与周围细胞溶胶的环境不同，并根据细胞器的特定功能进行调整。

例如，动物细胞中消化分子和细胞碎片的溶酶体细胞器保持着比周围细胞溶胶更酸性的环境，因为其酶需要较低的pH值来催化反应。同样，线粒体内的pH值也受到调节，这有助于线粒体发挥其产生能量的功能。
 
此外，一些蛋白质需要适当的折叠和处理的氧化环境，但细胞质通常是还原的。因此，这些蛋白质是由内质网(ER)中的核糖体产生的，它维持必要的环境。蛋白质通常通过膜结合的囊泡在细胞内运输。
 
真核细胞的遗传物质在细胞核内被分隔开，细胞核被称为核膜的双层膜所包围。外壳上的小孔控制着哪些分子或离子可以进入或离开原子核。例如，信使RNA (mRNA) 通过这些孔离开细胞核以获取DNA中编码的基因指令到核糖体，在那里它们可以翻译成蛋白质。
 
细胞器还可以通过包含和中和危险物质来保护细胞。例如，过氧化物酶体进行的氧化反应产生对细胞有毒的过氧化氢，但它们还含有将其转化为无害的氧气和水的酶。因此，区域化允许真核细胞执行各种不同的功能，否则它们所需的环境或所产生的副产品是不相容的。

真核细胞的一个显著特征是其含有由膜包被的细胞器，例如细胞核和线粒体，这些细胞器负责……

Education

教育

JoVE Core

Molecular Biology

分子生物学

Unit 1

第一单元

DNA, Cells, and Evolution

DNA、细胞与进化

KEY TERMS AND CONCEPTS

关键术语与概念

Eukaryotic Compartmentalization

cell compartments in eukaryotes

Eukaryotic cells use compartments to organize many different jobs inside one cell. These compartments help separate processes so they can happen in the right place.

The compartment called the cytosol is the fluid part of the cell. It surrounds the other internal structures and helps support many cell processes.

Inside the cell, membrane-bound organelles create distinct microenvironments. A microenvironment is a small internal space with conditions that fit a specific task. This separation lets the cell run different reactions at the same time.

The nucleus is one of the main compartments in eukaryotic cells. It keeps the cell’s genetic material in a protected space and helps separate DNA-related activities from other work in the cytosol.

Compartmentalization is a key feature of eukaryotic cells. It improves organization and helps the cell control where important processes take place.

Cell Compartments in Eukaryotes

the dna helix

DNA Structure and Base Pairing

DNA has a helical structure that helps store genetic information. The double helix is the shape formed by two strands that twist around each other. This structure is a key feature of DNA in cells. The two strands are held together by base pairing. Bases on one strand match with bases on the other strand in a regular way. This pairing helps keep the DNA molecule stable and organized. The helix shape also helps explain how DNA fits into chromosomes and carries instructions for living things. By...

the central dogma

DNA to Protein: Central Dogma Steps

The central dogma explains how genetic information moves from DNA to RNA to protein. This flow is a key idea in molecular biology. It helps show how cells use genes to make the molecules that carry out work. DNA stores the instructions for making proteins. During transcription, a gene in DNA is copied into RNA. The RNA then carries that message to the next stage. In translation, the RNA message is used to build a protein. Proteins do much of the cell’s work, so this process connects genes to...

prokaryotic cells

Inside Prokaryotic Cell Structure

Prokaryotic cells have a simple internal structure compared with many other cells. They are usually divided into two groups: bacteria and archaea. These cells have no nucleus, so their DNA is not enclosed in a membrane-bound compartment. Instead, the genetic material is found in the nucleoid, a region where the DNA is located in the cell. Some prokaryotic cells also contain plasmids, which are small extra DNA molecules. A capsule may surround the cell and provide an additional outer layer. <br...

eukaryotic compartmentalization

Eukaryotic cells use compartments to organize many different jobs inside one cell. These compartments help separate processes so they can happen in the right place. The compartment called the cytosol is the fluid part of the cell. It surrounds the other internal structures and helps support many cell processes. Inside the cell, membrane-bound organelles create distinct microenvironments. A microenvironment is a small internal space with conditions that fit a specific task. This separation...

the tree of life - bacteria, archaea, eukaryotes

the-tree-of-life-bacteria-archaea-eukaryotes

How Life Is Classified Into Three Domains

The tree of life shows how organisms are related through evolution. Its root represents the common ancestor of all life on Earth. From that point, branches spread out like a tree. The tips of the branches represent living, or extant, species. Species that no longer exist, called extinct species, appear closer to the center of the tree. Today, these organisms are grouped into three domains: bacteria, archaea, and eukaryotes. Scientists still debate these divisions, so the tree of life keeps...

mutations

How Mutations Change DNA

Mutations are changes in DNA. They can alter the genetic code and affect how genes work. In high school biology, students often study mutations to understand how DNA changes can influence traits. The transcript focuses on two common mutation types: point mutations and frameshift mutations. A point mutation changes one nucleotide, which is one DNA building block. A frameshift mutation happens when nucleotides are added or removed and the reading frame shifts. These changes matter because they...

gene evolution - fast or slow?

Why Some Gene Regions Evolve Faster

Gene regions do not all change at the same rate. In eukaryotes, long stretches of DNA do not code for proteins or RNAs. Some of these non-coding regions include important regulatory sequences, but most have no known function. Because little or no selection pressure acts on them, they often change the fastest over evolutionary time. Protein-coding regions usually evolve more slowly. A change in a coding sequence can alter a protein and make it less effective at doing its job. That creates...

genome size and the evolution of new genes

genome-size-and-the-evolution-of-new-genes

How Genome Size Shapes New Genes

Genome size can vary widely, and it also helps show how new genes form. Every living organism has a genome, whether it uses RNA or DNA. Yet the size of that genome can be very different from one organism to another. One major difference is whether the organism is prokaryotic or eukaryotic. Prokaryotic genomes usually have little to no non-coding sequence, which means genes are packed closely together in operons along the chromosome. Eukaryotic genomes contain long stretches of non-coding DNA...

gene families

How Gene Families Evolve and Diversify

Gene families are groups of genes that are thought to come from a shared ancestor. They usually form when a gene is copied by mistake during cell division. The original gene stays under selection pressure to keep its job, while the extra copy can change more quickly over time. Some copied genes gain a new role in the organism. When that happens, they are called paralogs, which are two genes in the same species that evolved from one common ancestral gene. Gene families also include orthologs,...

types of genetic transfer between organisms

types-of-genetic-transfer-between-organisms

How Genes Move Within and Across Generations

Genetic transfer is the movement of genetic information from one organism to another. It happens in two main ways: vertical gene transfer and horizontal gene transfer. Vertical gene transfer moves genes from one generation to the next. It is much more common than horizontal gene transfer. Vertical gene transfer happens during both sexual reproduction and asexual reproduction. In both cases, one or more organisms pass some or all of their genome to their offspring. This kind of transfer occurs...

key terms and concepts

Learn how eukaryotic cells use the cytosol, nucleus, and membrane-bound organelles to create microenvironments and organize cell processes.

Cell Compartments in Eukaryotes | JoVE K12

molecular biology

JoVE Core 分子生物学通过清晰简洁的动画视频课程展示了细胞的分子过程。此外，在科学家在行动的视频中，这些概念的应用是通过现代实验室中的真实实验演示的。

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Cell Compartments in Eukaryotes

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