There are millions of different kinds of organisms. Of these, only viruses are non-cellular life forms. All the rest have their own cell, the smallest, but the main structural unit. Therefore, it is an important indicator of the individuality of a creature, belonging to one or another kingdom of wildlife. Parts and organelles of the cell can explain how the body lives and grows, what processes occur inside it. Knowledge of the structure of this structural unit is important for understanding the whole living nature as a whole.
General plan of cell structure
A cell under a microscope is an interesting sight. It is simply amazing how much is hidden from the human eye and exists at the level of the microworld! With the invention of this unique optical device, it became possible to become part of this level, to study and understand its life mechanisms, learn to intervene in them and use them for the benefit of people.
So, it was found that not all organisms have the same structural units. Differences are present in almost every representative of the kingdom. For example, the main parts of a plant cell are different from those in animals. The structures of bacteria and fungi have their own characteristics. However, one can still single out the general principles of cell structure.
- Genetic material in the form of DNA molecules (for eukaryotic organisms - plants, fungi, animals - concentrated in the nucleus, prokaryotes (bacteria) do not have a nucleus formed).
- A cytoplasmic membrane that delimits internal content from external space and exposure.
- Cytoplasm with organoids and inclusions.
Many organoids are also the same for all cells, which once again confirms the unity of origin of all living things on our planet. There are a lot of structural parts in each living unit. It is, for example, about:
- mitochondria;
- lysosomes;
- Golgi apparatus;
- EPS (endoplasmic reticulum or reticulum);
- ribosomes;
- inclusions of protein and carbohydrate nature and others.
There are also highly specific organoids that are characteristic only for representatives of any particular kingdom of wildlife. For example, the main part of a plant cell is not only the nucleus, but also the cell wall, as well as the vacuole. Plastids are important, but these structures are not in animal units.
What are the most important parts of the cell?
The answer to this question is quite complicated. Indeed, without any of its structural parts, the cell will not be able to live and develop normally. But nevertheless, it is possible to distinguish several of the most significant organoids and parts in terms of the functions performed.
- A nucleus with nucleoli and genetic material concentrated on chromosomes.
- Cell wall (for plants), cytoplasmic membrane (all cells), mucous membrane (for bacteria).
- Cytoplasm with structural components.
The listed components are the basis of any cell, regardless of whether the body belongs to a particular species. Among the organelles of the cytoplasm, it is also possible to identify which parts of the cell are the most important.
- Mitochondria.
- Ribosomes.
- EPS.
- Lysosomes.
- Golgi apparatus (complex).
Obviously, the main part can be called the majority of all structural units of the unit structure of organisms.
The core and its structure
Historically, the main part of the cell is the nucleus. However, not all of them have it. So, there are no cores in:
- mature red blood cells;
- cells of conductive plant tissues ;
- bacteria.
There are also species in which, on the contrary, several cores. For instance:
- striated muscle;
- mushrooms;
- seaweed;
- milky plant vessels.
On the whole, the general structure plan of the structure in question is single. There are several main parts that make up any core.
- Karyolemma (nuclear membrane) - is a double membrane structure that acts as a barrier between the cytoplasm and the inner part of the nucleus. Ribosomes, EPS, Golgi complex are attached to it from the outside.
- Karyoplasma is an internal gel-like matrix filling the core. Another name is nucleoplasm. Contains different proteins, ribosomal RNA.
- Chromatin, capable of spiraling into tightly packed chromosomes during the period of division. Its composition is mainly provided by DNA strands. Also present are calcium and magnesium ions, proteins, RNA, lipids.
- Nuclei localized around chromosome regions. Consist of RNA, DNA, proteins. Serve for assembly of ribosome subunits, synthesis of r-RNA (ribosomal RNA).
This is a general plan of the structure of the nucleus, from which it is already obvious that the importance of this structure in each cell is crucial for the reproduction, storage and transmission of hereditary information, and the combination of genetic traits.
Cytoplasm and its meaning
The importance of this structure was discovered only with the invention of particularly powerful equipment to increase. Prior to this, it was assumed that it was simply a breeding ground for organoids. However, it has now been found that the cytoplasm has the following structure.
- The cytoskeleton is a complex of microfilaments and protein tubes that form the supporting network. Inside it, the organelles of the cell move.
- A cytosol or hyaloplasm is the colloidal internal content of the cytoskeleton, in which minerals, water are dissolved, lipids, proteins, carbohydrates are found. It is here that the processes of cell metabolism are carried out, the structures communicate with each other.
- Ectoplasm is the part of the cytoplasm adjacent directly to the membrane. Endoplasm - the entire space located between the karyolemma and ectoplasm.
In the cytoplasm, processes of intracellular transport take place, which allows all components to be in close contact. It is thanks to the constant dynamic movement of the structure under consideration that the organoids inside the cell move.
Cytoplasmic membrane
It is a bilipid elastic layer penetrated by protein molecules. The most common theory of the structure of a given organoid is the liquid-mosaic model. It serves to separate the external and internal environment of the cell. It has selective permeability, therefore it protects and protects against the ingress of foreign particles. In many ways, it maintains the shape of the cell.
If you answer the question: “What are the most important parts of the cell?”, Then the membrane will be the first, because each of them has it. Differences in composition appear in different species of organisms. For bacteria, the chitin included in the composition is characteristic, for animals - its absence.
Mitochondria
These structures are not in vain called energy, or "power stations" of cells. After all, it is in them that oxidative phosphorylation processes occur, as a result of which energy is released from ATP (adenosine triphosphoric acid) molecules. In the future, this energy is the source of all life processes, both internal and external.
The names of the parts of the cell were not always taken immediately. In the case of mitochondria, initially in 1894 these structures were described under the name of bioblasts.
The structure of this organelle itself is quite interesting. The outer membrane is two-layer. The inner layer has a folded structure, forms cristae, on which numerous ribosomes are located.
Mitochondria have their own DNA and two types of RNA (transport and matrix). A protein complex is also present. The number of structures under consideration in the cell can fluctuate, that is, depends on the activity of the organ. The largest number of mitochondria contain muscle cells.
Ribosomes
Small rounded dark structures that are visible when the cell is examined under an electron microscope are called ribosomes. These are also the main parts of the cell, because they are directly involved in the assembly of protein molecules.
By themselves, they are represented by ribonucleoprotein and make up a quarter of the total mass of the cell. They consist of two unequal subunits combined in one rounded shape. Attached to the Golgi complex, EPS, mitochondria, nucleus. Located inside some parts.
It is in the ribosomes that protein molecules are synthesized, which are necessary for all processes of plastic and energy metabolism.
Endoplasmic reticulum
A cell under a microscope resembles a highly stripped maze. This is due to such a structure as EPS or endoplasmic reticulum. It represents a whole network of branched channels and tubules, vesicles, which entangle all organelles and are especially closely concentrated around the nucleus.
It is through these tubes and channels that various particles move (transport) from one part of the cell to another. Therefore, EPS is also one of its main structures.
Cell wall and vacuole - parts of a plant cell
If you answer the question: "What parts of the cell are the most important in plants?", Then, in addition to the above, a few more should be added. This is primarily a cell wall. This is a dense membrane following the cytoplasmic membrane. It consists of cellulose and other carbohydrates and provides extra strength to cells. At trees, it is impregnated with a special substance - lignin. That is why their trunks are so durable. Also, it is the cell wall that is the structure that forms the shape of the cell as a whole.
Vacuole is the largest part of the plant's building units. It occupies almost the entire volume of the inner space of the cell. It is filled from the inside with a liquid that is a cell juice. This is a mixture of water, vitamins, minerals, hormones, carbohydrates.
Plastids
Another component of a plant cell is plastids. Presented in three varieties:
- leukoplasts are colorless;
- chromoplasts - red, orange, yellow pigments;
- chloroplasts - contain the green pigment chlorophyll.
The latter are the most important, since they are directly involved in the processes of photosynthesis.