To study the processes occurring in the body,you need to know what happens at the cellular level. And there protein protein compounds play an important role. It is necessary to study not only their functions, but also the process of creation. Therefore, it is important to explain protein biosynthesis briefly and clearly. Grade 9 for this is best suited. It is at this stage that students have enough knowledge to understand this topic.
Proteins - what it is and why they are needed
These high-molecular compounds play a hugerole in the life of any organism. Proteins are polymers, that is, consist of many similar "pieces". Their number can vary from a few hundred to thousands.
In a cell, proteins perform many functions. Their role is also great at higher levels of organization: tissues and organs largely depend on the proper functioning of various proteins.
For example, all hormones are of protein origin. But it is these substances that control all the processes in the body.
Hemoglobin is also a protein, it consists of four chains, which are connected in the center by an iron atom. This structure provides the ability to carry oxygen by red blood cells.
There are many more functions of protein molecules that they perform clearly and without question. These amazing compounds are very diverse not only in their roles in the cell, but also in structure.
Where is the synthesis
Рибосома является органеллой, в которой проходит the main part of the process, called "protein biosynthesis". Grade 9 in different schools differs in the program of studying biology, but many teachers give material on organelles in advance, before studying translation.
Therefore, it will not be difficult for students to recallcovered material and fasten it. You should know that only one polypeptide chain can be created on one organelle at a time. This is not enough to satisfy all the needs of the cell. Therefore, a lot of ribosomes, and most often they are combined with the endoplasmic reticulum.
But if you take into account the very beginning, butit is the reading of information from DNA, it can be said that protein biosynthesis in a living cell begins in the nucleus. It is there that matrix RNA is synthesized, which contains the genetic code.
Necessary materials - amino acids, place of synthesis - ribosome
It seems difficult to explain how the flowprotein biosynthesis, briefly and clearly, the process scheme and numerous drawings are simply necessary. They will help to bring all the information, as well as students will be able to remember it easier.
First of all, for the synthesis of necessary "building material" - amino acids. Some of them are produced by the body. Others can only be obtained with food, they are called indispensable.
It is the properties of these parts of each amino acid.determine the structure in which the resulting chain will “collapse”, whether it will form a quaternary structure with other chains, and what properties the resulting macromolecule will have.
So different and important ribonucleic acids
Для того чтобы принести аминокислоту к рибосоме, need a special RNA, called transport. To reduce its designate t-RNA. This single-stranded molecule in the form of a clover leaf is able to attach one amino acid to its free end and forward it to the place of protein synthesis.
Another RNA involved in protein synthesis,called matrix (informational). It carries an equally important component of the synthesis - a code in which it is clearly stated when what amino acid to cling to the resulting protein chain.
This molecule has a single-stranded structure,consists of nucleotides, as well as DNA. There are some differences in the primary structure of these nucleic acids, which you can read about in a comparative article on RNA and DNA.
Information on the composition of the protein m-RNA receives from the main custodian of the genetic code - DNA. The process of reading deoxyribonucleic acid and m-RNA synthesis is called transcription.
It occurs in the nucleus, from where the resulting m-RNA is sent to the ribosome. DNA itself does not come out of the nucleus, its task is only to preserve the genetic code and transfer it to the daughter cell during division.
Summary table of the main participants of the broadcast
In order to describe protein biosynthesis briefly and clearly, the table is simply necessary. In it, we write down all the components and their role in this process, which is called translation.
What is needed for synthesis | What role does |
Amino Acids | Serve as a building material for the protein chain. |
Ribosomes | Are the broadcasting venue |
t-RNA | Transports amino acids to ribosomes |
mRNA | Provides information on the sequence of amino acids in a protein to the site of synthesis. |
The process of creating a protein chain is divided into three stages. Let's look at each of them in more detail. After that, you can easily explain to everyone who is interested in protein biosynthesis briefly and clearly.
Initiation - the beginning of the process
This is the initial stage of translation, in which smallthe ribosome subunit is connected to the very first t-RNA. This ribonucleic acid carries the amino acid methionine. Translation always begins with this amino acid, since the start codon is AUG, which encodes this first monomer in the protein chain.
In order for the ribosome to recognize the start codon anddid not start the synthesis from the middle of the gene, where the AUG sequence may also be, there is a special nucleotide sequence around the initial codon. It is for him that the ribosome recognizes the place where its small subunit should sit.
After the formation of a complex with m-RNA, the initiation stage ends. And the main stage of the broadcast begins.
Elongation - the middle of the synthesis
At this stage, there is a gradual build-up of the protein chain. The duration of elongation depends on the amount of amino acids in the protein.
If the second codon on m-RNA coincides with the anticodon at the top of the "clover leaf", the second amino acid is attached to the first with the help of a peptide bond.
After that, the ribosome moves along m-RNA exactlythree nucleotides (one codon), the first t-RNA detaches methionine from itself and separates from the complex. In its place is the second t-RNA, at the end of which hangs already two amino acids.
Then the third t-RNA enters the large subunit and the process repeats. It will occur until the ribosome stumbles upon a codon in m-RNA, which signals the end of translation.
Termination
This stage is the last, to some it mayseem quite cruel. All molecules and organelles that worked so smoothly to create a polypeptide chain stop as soon as the ribosome runs into the terminal codon.
It does not encode any amino acid, thereforewhatever t-rnc goes into the large subunit, they will all be discarded due to inconsistencies. This is where termination factors come in, which separate the finished protein from the ribosome.
To understand the role of protein biosynthesis, it is necessarylearn what functions he can perform. It depends on the sequence of amino acids in the chain. It is their properties that determine the secondary, tertiary, and sometimes quaternary (if it exists) structure of the protein and its role in the cell. More information about the functions of protein molecules can be found in an article on this topic.
How to learn more about the broadcast
This article describes protein biosynthesis in livingcage. Of course, if you study the subject more deeply, it will take a lot of pages to explain the process in detail. But the above material should be enough for a general presentation. Video materials, in which scientists modeled all stages of the broadcast, can be very useful for understanding. Some of them are translated into Russian and can serve as an excellent tool for students or just informative video.
In order to understand the topic better, you should read other articles on similar topics. For example, about nucleic acids or about the function of proteins.
