Each cell of any organism has a complex structure that includes many components.
A brief about the structure of the cell
It consists of a membrane, cytoplasm, organelles that are located in them, as well as a nucleus (except for prokaryotes), in which DNA molecules are located. In addition, there is an additional protective structure above the membrane. In animal cells it is the glycocalyx, in all others it is the cell wall. In plants, it consists of cellulose, in fungi - of chitin, in bacteria - of murein. The membrane consists of three layers: two phospholipids and protein between them.
It has pores, through which the transfer of substances in and out. Near each pore are special transport proteins that allow only certain substances to enter the cell. The organelles of an animal cell are:
- mitochondria, which act as a kind of "power plants" (the process of cellular respiration and energy synthesis takes place in them);
- lysosomes, which contain special enzymes for metabolism;
- Golgi complex, designed to store and modify certain substances;
- endoplasmic reticulum, whichneeded for the transport of chemical compounds;
- centrosome, consisting of two centrioles that are involved in the division process;
- nucleolus, which regulates metabolic processes and creates some organelles;
- ribosomes, which we will discuss in detail in this article;
- plant cells have additional organelles: a vacuole, which is needed for the accumulation of unnecessary substances due to the inability to bring them out due to a strong cell wall; plastids, which are subdivided into leukoplasts (responsible for storing nutrient chemical compounds); chromoplasts containing colorful pigments; chloroplasts, which contain chlorophyll and where photosynthesis takes place.
The ribosome is what?
Since we are talking about her in this article, it is quite logical to ask such a question. The ribosome is an organelle that can be located on the outer side of the walls of the Golgi complex. It should also be clarified that the ribosome is an organelle that is contained in the cell in very large quantities. One can contain up to ten thousand.
Where are these organelles located?
So, as already mentioned, the ribosome is a structure that is located on the walls of the Golgi complex. It can also move freely in the cytoplasm. The third option where the ribosome can be located is the cell membrane. And those organelles that are in this place practically do not leave it and are stationary.
Ribosome - structure
Howwhat does this organelle look like? It looks like a telephone with a receiver. The ribosome of eukaryotes and prokaryotes consists of two parts, one of which is larger, the other is smaller. But these two parts of her do not join together when she is in a calm state. This happens only when the ribosome of the cell directly begins to perform its functions. We'll talk about functions later. The ribosome, the structure of which is described in the article, also contains messenger RNA and transfer RNA. These substances are necessary in order to write on them information about the proteins needed by the cell. The ribosome, the structure of which we are considering, does not have its own membrane. Its subunits (as its two halves are called) are not protected by anything.
What functions does this organoid perform in the cell?
What the ribosome is responsible for is protein synthesis. It occurs on the basis of information that is recorded on the so-called messenger RNA (ribonucleic acid). The ribosome, the structure of which we examined above, combines its two subunits only for the duration of protein synthesis - a process called translation. During this procedure, the synthesized polypeptide chain is located between two subunits of the ribosome.
Where do they form?
The ribosome is an organelle that is created by the nucleolus. This procedure takes place in ten stages, during which the proteins of the small and large subunits are gradually formed.
How do proteins form?
Protein biosynthesis occurs in several stages. The first oneis the activation of amino acids. There are twenty of them in total, and by combining them with different methods, you can get billions of different proteins. During this stage, amino allic-t-RNA is formed from amino acids. This procedure is impossible without the participation of ATP (adenosine triphosphoric acid). This process also requires magnesium cations.
The second stage is the initiation of the polypeptide chain, or the process of combining two subunits of the ribosome and supplying the necessary amino acids to it. Magnesium ions and GTP (guanosine triphosphate) also take part in this process. The third stage is called elongation. This is directly the synthesis of the polypeptide chain. Occurs by the method of translation. Termination - the next stage - is the process of disintegration of the ribosome into separate subunits and the gradual cessation of the synthesis of the polypeptide chain. Next comes the last stage - the fifth - is processing. At this stage, complex structures are formed from a simple chain of amino acids, which already represent ready-made proteins. Specific enzymes are involved in this process, as well as cofactors.
Protein structure
Since the ribosome, the structure and functions of which we have analyzed in this article, is responsible for the synthesis of proteins, let's take a closer look at their structure. It is primary, secondary, tertiary and quaternary. The primary structure of a protein is a specific sequence in which the amino acids that form a given organic compound are located. The secondary structure of a protein is formed from polypeptidealpha helix chains and beta folds. The tertiary structure of the protein provides for a certain combination of alpha helices and beta folds. The quaternary structure consists in the formation of a single macromolecular formation. That is, combinations of alpha helices and beta structures form globules or fibrils. According to this principle, two types of proteins can be distinguished - fibrillar and globular.
The first are such as actin and myosin, from which muscles are formed. Examples of the latter are hemoglobin, immunoglobulin and others. Fibrillar proteins resemble a thread, fiber. Globular ones are more like a tangle of alpha helices and beta folds woven together.
What is denaturation?
Everyone must have heard this word. Denaturation is the process of destroying the protein structure - first the quaternary, then the tertiary, and then the secondary. In some cases, the elimination of the primary structure of the protein also occurs. This process can occur due to the impact on this organic matter of high temperature. So, protein denaturation can be observed when boiling chicken eggs. In most cases, this process is irreversible. So, at temperatures above forty-two degrees, hemoglobin denaturation begins, so severe hyperthermia is life-threatening. Protein denaturation to individual nucleic acids can be observed during digestion, when the body breaks down complex organic compounds into simpler ones with the help of enzymes.
Conclusion
The role of ribosomes is very difficult to overestimate. They are the basis for the existence of the cell. Thanks to these organelles, it can create the proteins that it needs for a wide variety of functions. Organic compounds formed by ribosomes can play a protective role, a transport role, a catalyst role, a building material for a cell, an enzymatic, regulatory role (many hormones have a protein structure). Therefore, we can conclude that ribosomes perform one of the most important functions in the cell. Therefore, there are so many of them - the cell always needs products synthesized by these organelles.
