Have you ever heard of nucleoplasm? It is the internal environment of the cell nucleus (the most important part of the cell) and serves to support many substances involved in cell metabolism and gene expression.
In this article, we will know the most remarkable structure, composition, appearance and functions of this very specific part of the cell. Before that, however, we’ll go over the concept of a cell, and at the end of the article we’ll talk about the other components of the cell nucleus, beyond the nucleoplasm.
The cell as a basic unit
The cell is the basic unit of all living things; it is a microscopic structure, with the cell nucleus as the main component. Human beings are made up of millions and millions of cells, which are distributed throughout the body, making life possible.
In turn, the cell nucleus is made up of different components; one of them is the nucleoplasm, its internal and viscous environment.
But what exactly does this structure consist of? What features does it have? What is its appearance and composition? And its functions …? We’ll cover all of these issues in this article.
Nucleoplasm: what it is and general characteristics
Nucleoplasm (which is also given other names, such as nuclear cytosol, nuclear juice, nuclear matrix, karyoplasm, or karyolymph) it is the internal means of the cell nucleus, of semi-liquid character (It has a viscous texture). In other words, it forms the inner part of the cell nucleus, which is the most important part of cells (mainly because it contains the genetic material: DNA).
In the nucleoplasm, we can find two essential elements of the cell: DNA (genetic material) (in the form of fibers or chromatin) and RNA (ribonucleic acid) (in the form of fibers, called nucleoli). So we can say that this structure is made up of a number of elements that make gene expression possible.
As to its appearance, the nucleoplasm has a viscous texture, and is a semi-liquid medium. Its appearance is homogeneous, although it has a specific less viscous area, called the hyaloplasm.
What is found in the nucleoplasm?
Within the nucleoplasm are distributed various components of the cell nucleus, including: nucleotides (which allow the formation and replication of DNA), enzymes (responsible for directing the various activities developed in the nucleus itself) and the nucleolus (structure that transcribes ribosomal RNA).
What is its structure?
The nucleoplasm is part of the living material of the cell (located inside), which is called the protoplasm.
Structurally, the nucleoplasm is surrounded by the nuclear membrane, which separates it from the cytoplasm. In addition, the nucleoplasm separates the chromatin from the nucleolus (structures which we will explain later).
Composition: various substances
As for its composition, there are many substances that make up the structure of the nucleoplasm, or are found within it. In fact, its composition is similar to that of the cellular cytoplasm.
It should be noted that the nucleoplasm is 80% water. Water is its liquid phase, where there are dispersed organic compounds called compatible solutes.
On the other hand, the nucleoplasm is also formed by proteins and enzymes related to nucleic acid metabolism (DNA). Beyond these proteins, there are also others, called residual proteins, which are not bound to DNA or RNA, like the previous ones.
Finally, the nucleoplasm is also composed of other substances, such as precursor molecules, small water-soluble molecules (linked to cell signaling), cofactors (components necessary for the action of enzymes) and substances involved in the process of glycolysis. get energy from glucose).
Hormones and lipids
On the other hand, different hormones move through the nucleoplasm, linked to their respective nuclear receptors. These substances are steroid hormones and are basically the following: estrogen, testosterone, aldosterone, cortisol and progesterone.
Lipids are also found in the nucleoplasm (more precisely, they are suspended inside the nucleus of the cell), as well as phospholipids and fatty acids; the latter are involved in the regulation of gene expression.
We have seen the most relevant characteristics of the nucleoplasm, but what are its functions? Mainly, the nucleoplasm is the means which allows the development of certain chemical reactions, essential for the metabolic functions of the cell nucleus.
These reactions are usually caused by the random movement of molecules. This motion is called “Brownian motion” and consists of random collisions between molecules suspended in the nucleoplasm. It is a simple and non-uniform diffusion movement.
On the other hand, the aqueous medium constituting the nucleoplasm also facilitates the activity of enzymes, as well as the transport of various substances necessary for the proper functioning of the nucleus and, by extension, of the cell. All of this is possible, in large part, in its slimy texture.
Other parts of the cell nucleus
We have seen how the nucleoplasm is part of the nucleus of any cell and shapes its internal medium of viscous or semi-liquid texture. However, the core is also made up of other components, which are:
1. The nuclear envelope
This structure of the cell nucleus is, in turn, formed by an outer membrane and an inner membrane. Also called nuclear or karyotec membrane, it is a porous structure that separates the nucleoplasm from the outside.
2. The nucleolus
Also called a nucleolus, it is an area or structure in the cell nucleus, and functions to transcribe ribosomal RNA. It also participates in the regulation of the cell cycle, is involved in aging processes and regulates responses to cellular stress.
Chromatin is a presentation form of DNA located in the cell nucleus. consists of the basic substance of eukaryotic cell chromosomes (DNA, RNA and protein binding). In turn, chromatin can take two forms: heterochromatin and euchromatin.
ribosomes they are made up of RNA and ribosomal proteins, and allow the expression of genes, Through a process called translation.
5. The NPC (nuclear pore)
Finally, another component of the cell nucleus is the NPC or cell pores, which are large complexes of proteins that cross the membrane of the cell nucleus.
- Alberts et al. (2010). Molecular biology of the cell. (5th ed.). Omega Editorial.
- Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2002). Molecular Biology of the Cell (4th ed.). Garland Science, pages 120-121.
- Feynman, R. (1970). The Feynman Lectures on Physics Vol I. Addison Wesley Longman.
- Jiménez, F. and Merchant, H. (2003). Cellular and molecular biology. Part II Cell structures. Chapter 13 Ribosomes. Pearson Education, Mexico.
- Lodish et al. (2016). Cellular and molecular biology. (7th ed.). Pan American Medical Editorial.