Nucleoplasm is present inside the nucleus. It is the matrix in which all the nuclear components are present. Mainly nucleolus and chromatin are present in the nucleoplasm along with water, dissolved ions, and a complex mixture of molecules. It is a crucial part of the nucleus as it contains the genetic component of the cell. It is also called karyoplasm.

It was discovered along with the nucleus by Robert Brown in 1831. It is found only in eukaryotic cells as the nucleus is present only in these cells. In this article, we will discuss the nucleoplasm, its structure, diagram, components, and function of nucleoplasm.

Definition of Nucleoplasm

Nucleoplasm is a type of protoplasm that is composed of thick fluid and constitutes chromatin fibres made up of DNA and usually found in the nucleus of the eukaryotic cells.

What is Nucleoplasm?

The nucleoplasm is present inside the nucleus and is similar to the cytoplasm in consistency and the two together contribute to the protoplasm. The nucleolus, an organelle that is not membrane-bound is found inside the nucleoplasm. The nucleoplasm is responsible for maintaining the shape of the nucleus and also providing optimal conditions for genetic processes. Some components of the nucleoplasm include proteins, enzymes, ions, nucleotides, and nucleic acid. The soluble liquid component of the nucleoplasm is called the nuclear hyaloplasm.

Nucleoplasm Structure

Nucleosplasm is the fluid matrix of the nucleus. It is composed of water, proteins, ions, lipids, metabolites, etc. Several nuclear components like chromatin fibres, RNA, etc. remain suspended in the nucleoplasm. Nucleoplasm resembles an eukaryotic cytoplasm in composition and is confined within the nuclear membrane giving a distinct shape to the nucleus.

The major portion of the nucleoplasm is a solid fluid called hyaloplasm or karyolymph. It is composed of water and ions primarily. Suspended in this hyaloplasm, lies the chromosomes, RNAs, nucleolus, nuclear bodies, nuclear speckles, porins, etc. Nucleolus forms the dense region inside the nucleoplasm associated with the synthesis of ribosomal subunits and lies almost near the centre of the nucleoplasm.

Diagram of Nucleoplasm

The diagram of nucleoplasm is shown below:

Diagram of Nucleoplasm

Components of the Nucleoplasm

The nucleoplasm is a gel-like matrix that has structures like the nucleolus and chromatin suspended in it. The nucleoplasm has different components in specified proportions. These proportions are important for carrying out nuclear reactions and processes. The components of the nucleoplasm are as follows:

• Nucleotides: They are the building blocks of nucleic acids. Nucleotides are made up of a sugar molecule, phosphate group, and nitrogenous bases which include purines (Adenine and Guanine) and pyrimidines (Uracil, Thymine, and Cytosine).
• Chromatin: It is a complex of DNA, RNA, and proteins that help in the folding of DNA. The chromatin network is folded in such a way that it can regulate functions like replication and gene expression. Based on the chromatin folding, and DNA staining techniques it can be characterized as follows.
• Euchromatin: Less condensed and looks lightly stained in appearance. It is usually transcriptionally active.
• Heterochromatin: Highly condensed and appears dark after staining. It is found to be transcriptionally inactive.
• Matrix: It is important for the maintenance of the structure and organization of the nucleus. It is useful in organizing the genetic material of the cell.
• Nucleolus: The nucleolus is the major part of the nucleus which is responsible for ribosome production. It also produces key components of ribosome assembly. The subunits of ribosomes are synthesized by the nucleolus. It is the largest organelle in the nucleus and the organisms will not be able to survive without the nucleolus.
• Enzymes: Enzymes are required to increase the rate of chemical reactions. In the nucleoplasm, enzymes required for DNA replication like DNA polymerase along with other enzymes like aldolases, hexokinases, and dehydrogenases can be found.

What are the Major Functions of Nucleoplasm?

The involvement of nucleoplasm in the cellular functions is very important. It is the site of all compounds and products that are synthesized in the nucleus and then moved to other areas of the cell. The functions of the nucleoplasm are as follows.

• It is necessary for the maintenance of nuclear shape and structure.
• All the nuclear components are suspended in the nucleoplasm.
• Important for transport of essential material inside and out of the nucleus.
• Supports the chemical reactions with necessary enzymes and ions.
• Maintains optimal conditions for the reactions to occur.

Difference between Cytoplasm and Nucleoplasm

The difference between Cytoplasm and Nucleoplasm are stated below: