Every cell of any organism is a complex structure, including a plurality of components.Briefly
about cell structure
It consists of a membrane, cytoplasmic organelles, which are located, as well as the nucleus (except for prokaryotes), which contains the DNA molecule.In addition, over the membrane has an extra protective structure.In animal cells is the glycocalyx, all the rest - the cell wall.In plants, it is composed of cellulose, fungi - chitin, bacteria - from murein.The membrane consists of three layers: two phospholipid and protein therebetween.It has pores through which carried out the transfer of substances in and out.Near each pore are special transport proteins in the cell that transmit only certain substances.Animal cell organelles are:
- mitochondria, which act as the original "power" (in which the process of cellular respiration and the synthesis of energy);
- lysosomes that contain special enzymes for metabolism;
- Golgi complex for storing and modification of certain substances;
- endoplasmic reticulum, which is necessary for the transport of chemicals;
- centrosome consists of two centrioles, which are involved in the division;
- nucleolus, which regulates metabolism and creates some organelles;
- ribosomes, which we will talk in detail in this article;
- plant cells have additional organelles: the vacuole, which is necessary for the accumulation of unwanted substances in connection with the inability to output them out because of the strong cell wall;plastids, which are divided into leucoplasts (responsible for the storage of nutrient chemical compounds);chromoplasts containing color pigments;chloroplasts, which is where the chlorophyll and photosynthesis.
ribosome - what's that?
Since we are talking about it in this article, it is logical to ask this question.Ribosome - this organelle, which can be located on the outer side walls of the Golgi complex.It is necessary to clarify further that the ribosome - this organelle, which is contained in a cell in very large quantities.One can be up to ten thousand.
Where are these organelles?
So, as already mentioned, the ribosome - a structure that is on the walls of the Golgi complex.Also it can move freely in the cytoplasm.A third embodiment, where it can be located ribosome - the cell membrane.Both organelles which are found in this location virtually leave it and are stationary.
ribosome - the structure
How looks like this organelle?She looks like a mobile phone handset.Prokaryotic and eukaryotic ribosome is composed of two parts, one of which is more other - less.But the two of its components are not joined together, when it is at rest.This only happens when the ribosome cells immediately begin to perform their functions.Functions will be discussed later.The ribosome, a structure is described in the article, also it incorporates a messenger RNA and transfer RNA.These substances are needed in order to record them on the information about the relevant cell proteins.The ribosome, a structure which we are considering, has no membrane.Its subunit (the so-called two of her half) are not protected.
What does this organelle in the cell?
fact, responsible for what the ribosome - protein synthesis.It occurs on the basis of information which is recorded on the so-called messenger RNA (ribonucleic acid).The ribosome, a structure where we have seen above, joins the two subunits only during protein synthesis - the process called translation.During this procedure, the synthesized polypeptide chain located between the two subunits of the ribosome.
Where are they formed?
ribosome - organelle that is created nucleolus.This procedure takes place in ten stages, during which proteins gradually formed small and large subunits.
How is the formation of proteins?
protein synthesis occurs in several stages.The first of these - is the activation of amino acids.A total of twenty-exist, by combining them in different ways, you can get billions of different proteins.During this stage of the amino acids formed aminoalits-tRNA.This procedure is not possible without the participation of ATP (adenosine triphosphate).Also, for the implementation of this process requires magnesium cations.The second stage - the initiation of the polypeptide chain, or the process of unification of the two subunits of the ribosome and delivery to it of essential amino acids.In this process also participate magnesium ions and GTP (guanosine triphosphate).The third step is called elongation.This has a direct synthesis of the polypeptide chain.There is a method of broadcasting.Termination - the next step - a process of disintegration into individual subunits of the ribosome and the phasing out of the synthesis of the polypeptide chain.Next comes the last step - the fifth - a processing.At this stage of the single chain of amino acids form complex structures that are already ready proteins.This process involves the specific enzymes and cofactors.
Protein Structure
Since the ribosome structure and function that we discussed in this article, is responsible for the synthesis of proteins, then let's look at the details of their structure.It is a primary, secondary, tertiary and quaternary.The primary structure of the protein - a certain sequence in which amino acids are arranged forming this organic compound.The secondary structure of a protein is a polypeptide chain formed from alpha-helices and beta-sheets.The tertiary structure of the protein provides a specific combination of an alpha-helix and beta-sheet.The quaternary structure is the formation of a single macromolecular education.That is a combination of alpha-helices and beta structures form globules or fibrils.According to this principle, there are two types of proteins - fibrous and globular.Among the former are such as actin and myosin, which are formed of muscles.Examples of the latter can serve as hemoglobin, immunoglobulin and others.Fibrillar proteins resemble a filament fiber.Globular more like a ball of woven between an alpha-helices and beta-sheet.
What denaturation?
Everyone must have heard the word.Denaturation - is the process of destroying the structure of the protein - first quaternary, tertiary and then, and then - and secondary.In some cases there and elimination of the primary structure of the protein.This process may result from exposure to this high temperature of the organic substance.Thus, protein denaturation can be observed when cooking eggs.In most cases, this process is irreversible.For example, at a temperature above forty-two degrees begins the denaturation of hemoglobin, so severe hyperthermia is life threatening.Denaturation of proteins to specific nucleic acids can be observed in the process of digestion when using the enzymes the body breaks down complex organic compounds into simpler.
Conclusion
role of ribosomes is difficult to overestimate.They are the basis for the existence of the cell.Due to these organelles it may produce proteins that were required for a variety of functions.Organic compounds formed by ribosomes, may play a protective role, transport, as a catalyst, building material for cells, enzymatic, regulatory (hormones have many protein structure).Therefore, we can conclude that the ribosome to perform one of the most important functions in the cell.Therefore, they and so many - cell always need the products synthesized these organelles.
