We explain what the cell nucleus is and what its main characteristics are. Also, the functions it performs and what its structure is like.
What is the cell nucleus?
The cell nucleus is a small spheroid or oval-shaped structure which is found (usually) in the center of the nucleus of eukaryotic cells and which contains all the genetic material of the organism.
It is the main organelle of cells and is considered the operational center because it is responsible for controlling cellular activities. In addition, it stores and maintains the integrity of all the genetic information of the organism so that, at the appropriate time, said information is transmitted to the daughter cells.
Inside the cell nucleus are DNA and RNA molecules and structures such as the cell envelope and the nucleolus, which is a dense, spherical region of the nucleus that has the function of producing and assembling ribosomes.
See more: Plant cell
Characteristics of the cell nucleus
Some of the main characteristics of the cell nucleus are:
- It is the largest organelle within the cell and its shape can be circular or ovoid.
- It is present only in eukaryotic cells of organisms, such as animals, plants, and fungi.
- It stores all the genetic information of the individual.
- It is the operating center of the cell.
- It is usually located in the center of the cell, although in some cases it can be found on the cell periphery.
- It is a fundamental part of the ribosome generation process.
- It is made up of different structures such as the nucleolus, chromatin and cell envelope.
Functions of the cell nucleus
The cell nucleus is only found in eukaryotic cells.since prokaryotic cells are usually found in unicellular organisms that are characterized by having the genetic material loose in the cytoplasm and not in a cell nucleus.
One of the main functions of this organelle is store genetic information of the organismthat is, storing the genes that are inside the DNA molecules and form part of the chromatin and, at the time of interphase, organizing them within chromosomes. This genetic information stored in the cell nucleus is essential in different vital processes such as cell division.
Furthermore, the core is responsible for controlling cellular activity, and within this structure the information from DNA is transcribed into ribosomal RNA, which has, among other functions, protein synthesis. This protein synthesis takes place in ribosomes, which are organelles that are in the cytoplasm of the cell and are created by the nucleolus within the cell nucleus.
Structure and elements of the cell nucleus
The main elements that make up the cell nucleus are:
- 1. Nuclear envelope or membrane. It is the element that covers the nuclear content, gives it structure and separates it from the cytoplasm. Its main function is to protect the nucleus and is subdivided into: outer membrane and inner membrane. These membranes remain separated by a space called “perinuclear space.”
-
- Outer membrane. It is a membrane with a rough appearance due to the presence of ribosomes in its surface composition. It is located between the cytoplasm and the perinuclear space.
- Inner membrane. It is a membrane that does not contain ribosomes and is located between the perinuclear space and the nucleoplasm.
- 2. Perinuclear space and nuclear pores. The perinuclear space is the structure that is formed between the inner and outer membranes and is made up of nuclear pores that allow the passage of substances between the nucleus and the cytoplasm.
- 3. Nucleoplasm, karyolymph or nuclear juiceIt is the aqueous medium that forms part of the interior of the cell nucleus and in which the chromatin and the nucleolus are found. In addition, it is made up of water, molecules, hormones, enzymes, among others. Its main functions are: to support the chromatin, the nucleolus and to be the medium in which chemical reactions of the metabolic process take place.
- 4. Chromatin. It is a substance composed of nucleoproteins and nucleic acids (DNA and RNA). DNA, which is usually very long, is condensed in chromatin. During cell division, chromatin is transformed into thick structures called chromosomes. There are two types of chromatin:
-
- It is the chromatin with the highest level of condensation.
- It is the most abundant chromatin but has the lowest level of condensation.
- 5. DNA (deoxyribonucleic acid). It is the nucleic acid that carries the genetic material that each individual has and is capable of replicating itself to transmit the morphological and physiological characteristics of the individual from generation to generation. DNA is found in the nucleus of the cells of living beings and its structure resembles a double helix formed by two chains of nucleotides. In addition, a small portion of DNA is present in the mitochondria (a cell organelle that supplies energy).
- 6. RNA (ribonucleic acid)It is the nucleic acid responsible for transmitting vital DNA information and producing the proteins that cells need for their activity and development. It has a simple chain structure and there are different types depending on their function: messenger RNA, transfer RNA and ribosomal RNA.
- 7. The nucleolusIt is a structure that forms part of the nucleus and is made up of proteins and synthesizes ribosomal RNA. It is dense and spherical and the number of nucleoli within the nucleus depends on each type of cell. Its main function is the assembly of ribosomes.
Continue with: Lysosomes