nucleoid

简明释义

英[ˈnjuːklɪˌɔɪd]美[ˈnuːkliˌɔɪd]

n. [病毒] 病毒核心；[细胞] 类核

英英释义

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例句

1.The results showed that the RLO with an integrated cell membrane and a nucleoid of low electronic density appeared in the cytoplasm .

研究表明，该病原体具有完整的细胞包膜，内部具有低电子密度拟核，在胞浆中以两种类型存在-繁殖型和静止型；

2.The results showed that the RLO with an integrated cell membrane and a nucleoid of low electronic density appeared in the cytoplasm .

研究表明，该病原体具有完整的细胞包膜，内部具有低电子密度拟核，在胞浆中以两种类型存在-繁殖型和静止型；

3.The RLO with cell wall was smaller than bacteria but larger than virus and had cell membrane without nucleoid area.

该微生物的大小介于病毒和细菌之间，具有明显的细胞壁和细胞膜双层结构，但无明显的细胞核。

4.The bacterium's genetic material is located in the nucleoid, which is not surrounded by a membrane.

细菌的遗传物质位于核糖体中，周围没有膜包围。

5.In prokaryotic cells, the nucleoid contains the majority of the cell's DNA.

在原核细胞中，核糖体包含大部分细胞的DNA。

6.Researchers studied the structure of the nucleoid to understand bacterial reproduction.

研究人员研究了核糖体的结构，以了解细菌的繁殖。

7.The absence of a true nucleus distinguishes prokaryotes from eukaryotes, as they have a nucleoid instead.

真核生物与原核生物的区别在于缺乏真正的细胞核，后者有一个核糖体。

8.The nucleoid is essential for the cell's function, as it houses the information needed for protein synthesis.

核糖体对细胞的功能至关重要，因为它存储了合成蛋白质所需的信息。

作文

In the study of cellular biology, one of the fundamental concepts is the structure and organization of cells. Cells are often categorized into two main types: prokaryotic and eukaryotic. A key feature that distinguishes these two types of cells is the presence or absence of a defined nucleus. In prokaryotic cells, instead of a nucleus, there is a region called the nucleoid, which is essential for understanding how these organisms function. The nucleoid (核糖体) is not surrounded by a membrane; rather, it is a concentrated area within the cell that contains the genetic material, primarily in the form of circular DNA. This structure is critical for the survival and reproduction of prokaryotic organisms, such as bacteria. The nucleoid plays a vital role in the processes of transcription and replication of DNA. Unlike eukaryotic cells, where DNA is housed within a membrane-bound nucleus, the nucleoid allows for a more direct interaction between the genetic material and the cellular machinery that reads and replicates it. This proximity can lead to faster responses to environmental changes, which is particularly advantageous for prokaryotic organisms that often inhabit fluctuating environments. Furthermore, the organization of DNA within the nucleoid is quite distinct. The DNA is typically supercoiled and associated with proteins that help compact it into a manageable form. This organization is crucial because it allows the relatively small volume of the nucleoid to house a significant amount of genetic information. The ability to efficiently package DNA is one of the reasons why prokaryotes can thrive in diverse habitats, from extreme heat to high salinity. Another interesting aspect of the nucleoid is its dynamic nature. During cell division, the genetic material must be accurately replicated and distributed to daughter cells. The mechanisms involved in this process are fascinating and highlight the adaptability of prokaryotic cells. As the cell grows, the nucleoid can change shape and size, reflecting the cell's metabolic state and its need to respond to various stimuli. This flexibility in the organization of the nucleoid underscores the efficiency of prokaryotic cells in managing their genetic resources. In conclusion, the nucleoid is a defining characteristic of prokaryotic cells that significantly impacts their biology and ecology. Understanding the structure and function of the nucleoid provides insights into the evolutionary adaptations of these organisms. As scientists continue to explore the complexities of cellular life, the role of the nucleoid will undoubtedly remain a focal point of research, revealing more about how life operates at the microscopic level and how these simple yet highly efficient cells have thrived on Earth for billions of years.

在细胞生物学的研究中，一个基本概念是细胞的结构和组织。细胞通常被分为两种主要类型：原核细胞和真核细胞。区分这两种细胞类型的一个关键特征是是否存在明确的细胞核。在原核细胞中，取而代之的是一个叫做nucleoid（核糖体）的区域，这对于理解这些生物体如何运作至关重要。nucleoid并没有被膜包围；相反，它是细胞内一个浓缩的区域，包含遗传物质，主要以环状DNA的形式存在。这个结构对原核生物（如细菌）的生存和繁殖至关重要。 nucleoid在DNA的转录和复制过程中发挥着重要作用。与真核细胞不同，真核细胞中的DNA被封闭在膜包围的细胞核内，而nucleoid则允许遗传物质与读取和复制它的细胞机制之间进行更直接的互动。这种接近性可以导致对环境变化的更快反应，这对于常常生活在波动环境中的原核生物尤其有利。 此外，nucleoid内DNA的组织方式也相当独特。DNA通常是超螺旋的，并与帮助将其压缩成可管理形态的蛋白质结合。这种组织至关重要，因为它允许nucleoid相对小的体积容纳大量的遗传信息。有效包装DNA的能力是原核生物能够在极端热量到高盐度等多样栖息地中生存的原因之一。 nucleoid的另一个有趣方面是它的动态性质。在细胞分裂期间，遗传物质必须被准确复制并分配给子细胞。参与这一过程的机制非常迷人，并突显了原核细胞的适应能力。当细胞生长时，nucleoid可以改变形状和大小，反映细胞的代谢状态及其对各种刺激的反应需求。这种nucleoid的组织灵活性凸显了原核细胞在管理其遗传资源方面的高效性。 总之，nucleoid是原核细胞的一个决定性特征，显著影响它们的生物学和生态学。理解nucleoid的结构和功能提供了对这些生物体进化适应的见解。随着科学家们继续探索细胞生命的复杂性，nucleoid的角色无疑将继续成为研究的重点，揭示有关生命在微观水平上如何运作以及这些简单但高效的细胞如何在地球上生存了数十亿年的更多信息。