Cell Nucleus and Nuclear Envelope

The nucleus of a eukaryotic cell contains the DNA, the genetic material of the cell. The DNA contains the information necessary for constructing the cell and directing the multitude of synthesis tasks performed by the cell in the process of life and reproduction.

真核细胞的细胞核含有DNA，这是细胞的遗传物质。DNA包含了构建细胞和指导细胞在生命过程和繁殖过程中进行多种合成任务所必需的信息。

The nuclear envelope surrounds the nucleus with a double membrane with multiple pores. The pores regulate the passage of macromolecules like proteins and RNA, but permit free passage of water, ions, ATP and other small molecules. In this way the membrane exerts some control over the information flow in the cell since information is carried by the macromolecules.

细胞核被双层膜包围，膜上有多个孔道。这些孔道调节大分子如蛋白质和RNA的通过，但允许水、离子、ATP和其他小分子自由通过。因此，膜在一定程度上控制了细胞内的信息流动，因为信息是通过大分子传递的。

Inside the nuclear envelope is the chromatin, meaning "colored substance" after the early experiments in which that material was highly colored by the staining techniques used. Chromatin consists of DNA associated with proteins which forms long strands called chromosomes. While the DNA remains in the nucleus, it controls most of the processes that occur in the cytoplasm of the cell. Information from the DNA can be transcribed to mRNA and transmitted to other cellular synthesis processes, and information from the cytoplasm can provide feedback to the nucleus.

在核膜内侧是染色质，'染色质'这一名称源于早期实验中，该物质通过染色技术被强烈染色。染色质由DNA与蛋白质结合形成长长的染色体。当DNA位于细胞核内时，它控制着细胞质中大多数发生的过程。DNA中的信息可以转录到mRNA并传递到其他细胞合成过程，而细胞质中的信息也可以反馈给细胞核。

The nucleolus is the central portion of the cell nucleus and is composed of ribosomal RNA, proteins and DNA. It also contains ribosomes in various stages of synthesis. The nucleolus accomplishes the manufacture of the ribosomes.

细胞核的核仁是细胞核的中央部分，由核糖体RNA、蛋白质和DNA组成。它还包含处于不同合成阶段的核糖体。核仁负责制造核糖体。