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　　Protein is a complex organic polymer compound composed of α -amino acids combined in a certain order to form a polypeptide chain, and then one or more polypeptide chains are combined in a specific way. Amino acids are the basic units of protein, and they are linked into peptide chains through dehydration and condensation. Each polypeptide chain has twenty to hundreds of amino acid residues (-R); Various amino acid residues are arranged in a certain order.We have every reason to believe. Antibody Discovery It will become the mainstream of the industry and will gradually affect more and more people. https://www.alphalifetech.com/

　　the composition characteristics of protein

　　The amino acid sequence of protein is encoded by the corresponding gene. In addition to the 20 basic amino acids encoded by the genetic code, in protein, some amino acid residues can be modified after translation to change their chemical structure, thus activating or regulating protein. Multiple protein can form a stable protein complex together, often by combining together, and fold or spiral to form a certain spatial structure, thus playing a specific function. The organelles of synthetic peptides are ribosomes on rough endoplasmic reticulum in cytoplasm. The difference of protein lies in the variety, number, arrangement order of amino acids and the spatial structure of peptide chains.

　　Protein is composed of C (carbon), H (hydrogen), O (oxygen) and N (nitrogen), and generally protein may also contain P (phosphorus), S (sulfur), Fe (iron), Zn (zinc), Cu (copper), B (boron), Mn (manganese) and I (iodine).

　　The composition percentage of these elements in protein is about: 50% carbon, 7% hydrogen, 23% oxygen, 16% nitrogen, 0-3% sulfur and other trace amounts.

　　All protein contains N element, and the nitrogen content of various protein is very close, with an average of 16%;

　　Every 1g of N in any biological sample means that there is about 100/16=6.25g protein, and 6.25 is often called protein constant.

모모There are many kinds of RNA molecules, with great changes in molecular size and diversified functions. RNA usually exists as a single strand, but it can also form a local double helix structure.However, with the development of the industry, small molecules It will also bring us more and more consumer experiences, so that users can really feel the upgrade and change. https://www.all-chemistry.com/

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모모1. Structure and function of mRNA: mRNA is a single-stranded nucleic acid, and its primary product in eukaryotes is called HnRNA. Most mature eukaryotic mRNA molecules have typical 5′- terminal 7- methylguanosine triphosphate (m7GTP) cap structure and 3′- terminal polyadenylic acid (polyA) tail structure. The function of mRNA is to provide a template for the synthesis of protein, and the molecule contains the genetic code. Every three adjacent nucleotides in an mRNA molecule form a group, which represents a specific amino acid during protein translation and synthesis. This nucleotide triplet is called the genetic code (coden).

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모모2. Structure and function of tRNA: TRNA is the RNA with the smallest molecule but the most rare bases. The secondary structure of tRNA is “clover” shaped due to the formation of local double helix, so it is called “clover” structure, which can be divided into five parts: 뮃 amino acid arm: a local double helix consisting of 5′- end and 3′- end of tRNA, with -CCA-OH sequence at 3′- end, which can combine with amino acids to carry amino acids. 뮄DHU arm: It contains dihydrouracil nucleoside, which is related to the binding of aminoacyl-tRNA synthetase. 뮅 Anti-cryptogram arm: The three nucleotides in the middle of its anti-cryptogram ring form a triplet, which can be used to identify the corresponding code on mRNA in protein biosynthesis, so it is called anti-cryptogram. 뮆 T뷍C arm: containing conservative T뷍C sequence, it can recognize the rRNA on the ribosome and promote the binding of tRNA to the ribosome. 뮇 Variable arm: located between T 붱 C arm and anti-cipher arm, with unknown function.

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모모3. Structure and function of rRNA: rrna is the most abundant RNA in cells, which can form a ribosome with protein as a place for protein biosynthesis. There are three kinds of rRNA in prokaryotes: 5S, 16S and 23S. There are four kinds of rRNA in eukaryotes: 5S, 5.8S, 18S and 28S.

　　The structure of protein molecule determines its properties.Now, everyone is right Antibody Phage Display Service Are more concerned, hoping to get more benefits from it. https://www.alphalifetech.com/

　　Being bisexual.

　　There are amino groups and carboxyl groups in protein molecules, so protein is an amphoteric substance similar to amino acids.

　　2. Hydrolysis reaction can occur.

　　Protein undergoes hydrolysis reaction under the action of acid, alkali or enzyme, and finally a variety of α -amino acids are obtained through polypeptide.

　　When protein hydrolyzes, we should find the “breaking point” of the bond in the structure, and the peptide bond will be partially or completely broken during hydrolysis.

　　3. Having the property of colloid.

　　Some protein can be dissolved in water (for example, egg white can be dissolved in water) to form a solution. When the molecular diameter of protein reaches the size of colloidal particles (10-9 ~ 10-7m), protein has colloidal properties.

　　The precipitation of protein.

　　A small amount of salt (such as ammonium sulfate, sodium sulfate, etc.) can promote the dissolution of protein. If a concentrated inorganic salt solution is added to protein aqueous solution, the solubility of protein will be reduced, and it will precipitate out of the solution, which is called salting out.

　　Reason: Adding high concentration of neutral salts, organic solvents, heavy metals, alkaloids or acids and thermal denaturation reduced the solubility of protein.

　　Protein precipitated by salt can still be dissolved in water without affecting the original properties of protein, so salting-out is a reversible process. Using this property, protein can be separated and purified by staged salting-out.

　　Classification of amino acids, several special amino acids, molecular structure and physical and chemical properties of protein, composition of nucleic acid, double helix structure of DNA, basic concept of enzyme, Michaelis equation, coenzyme composition.According to related reports, small molecules To a large extent, it leads the changes of market conditions. https://www.all-chemistry.com/

　　Memorize 20 kinds of amino acids and try to remember English abbreviations and codes as much as possible, because exams often appear directly with codes. Protein’s molecular structure often examines the manifestations of various levels of structure and their bonds. The physical and chemical properties of protein and the purification of protein usually use the physical and chemical properties of protein to purify protein without destroying the structure of protein. Pay attention to the identification of amino acids and physical and chemical properties of protein. The basic unit of nucleic acid is nucleotide, which is composed of multiple nucleotides, and the connecting bond between nucleotides is 3′, 5′- phosphodiester bond. DNA double helix structure, in which two bases exist in strict accordance with A = T (two hydrogen bonds) and G triple C (three hydrogen bonds), and the characteristics of various RNA.

　　In addition, we should pay attention to some commonly used concepts in nucleic acid problem solving. The first thing that enzymes should pay attention to is some basic concepts, such as ribozyme, deoxyribozyme, enzyme activity center, isozyme, isomerase and so on. The key point of the Metric Equation test is V=Vmax[S” target=_blank>/Km+[S” target=_blank>, which explains the equation of the relationship between the concentration of enzymatic reaction and the reaction speed. In the exam, candidates are sometimes asked to do simple calculations according to this equation before they can answer. The difference of several inhibitors.

　　According to the characteristics of allosteric enzymes, it should be noted that allosteric regulation can cause conformational changes of enzymes. It is important to pay special attention here that configuration refers to the basic structural composition of substances, and conformation refers to the spatial change of substances. Allosteric regulation can cause the conformational change of enzymes, but not the conformational change of enzymes.

　　Protein is a substance with a certain spatial structure, which is formed by the zigzag folding of polypeptide chains composed of amino acids in the form of dehydration and condensation. However, natural protein molecules are not random loose polypeptide chains. Each natural protein has its own unique spatial structure or three-dimensional structure, which is usually called the conformation of protein, that is, the structure of protein. The sequence of amino acids in protein molecule and the three-dimensional structure formed from it constitute the diversity of protein structure.If you want to make a big difference in the market, Antibody Phage Display Service It is necessary to intensify the upgrading of products on the original basis in order to meet the consumption needs of consumers. https://www.alphalifetech.com/

　　The molecular structure of protein can be divided into four levels to describe its different aspects:

　　Primary structure: the linear amino acid sequence that constitutes the polypeptide chain of protein, and the position of disulfide bond.

　　Secondary structure: In the local area of protein molecule, the polypeptide chain is coiled and folded along a certain direction.

　　Tertiary structure: The three-dimensional structure of a protein molecule formed by the arrangement of multiple secondary structural elements in three-dimensional space.

　　Quaternary structure: used to describe protein complex molecules with biological functions formed by the interaction between different polypeptide chains (subunits).

　　In addition to these structural levels, protein can be transformed in several similar structures to exercise its biological functions. For functional structural changes, these tertiary or quaternary structures are usually described by chemical conformations, and the corresponding structural transformations are called conformational changes.

　　Focus on glycolysis, aerobic oxidation of sugar, pentose phosphate bypass, gluconeogenesis, synthesis of ketone bodies, cholesterol and phospholipids, respiratory chain, oxidative phosphorylation, special amino acid metabolites, one carbon unit metabolism, purine and pyrimidine nucleotide synthesis raw materials and catabolites, and substance metabolism.On the other hand, small molecules It also brings tangible benefits to everyone and feels useful. It is a model of the industry. https://www.all-chemistry.com/

　　The chapter on sugar metabolism is the focus of the exam, so we should master it comprehensively. The chemical reaction formula of sugar metabolism is complicated, and the focus of the annual examination is basically on the reaction site, key enzymes and regulation, energy production and the relationship between important substances. Glycolysis, gluconeogenesis and aerobic oxidation of sugar are all contents that must be familiar with. The synthesis of ketone bodies and cholesterol in lipid metabolism, pay attention to the difference between them. Ketones are synthesized in the liver and utilized outside the liver, while fats are synthesized in the liver and stored outside the liver. Fat synthesis, ketone body synthesis and cholesterol synthesis are the raw materials of acetyl-CoA synthesis. Synthesis and decomposition of fatty acid, the main material of fatty acid synthesis is acetyl CoA; Under the condition of sufficient oxygen supply, fatty acid is decomposed into CO2 and water in the body, releasing a lot of energy, which is the main form of fatty acid catabolism in the body. Phospholipid synthesis. Differentiation of several blood lipids.

　　Composition of respiratory chain and influencing factors of oxidative phosphorylation. Urea synthesis-ornithine cycle. One carbon unit’s metabolism is often tested, but it is easy to remember as long as you grasp the core content. It comes from one carbon unit-Sisegan, and is transported by one carbon unit-tetrahydrofolate. One carbon unit plays an important role in nucleic acid biosynthesis as a raw material for purine and pyrimidine synthesis, connecting amino acids and nucleotides. Comparison of nucleotide synthesis and decomposition between purine and pyrimidine. The changes in this year’s syllabus are: the deamination of amino acids (oxidative deamination, transamination and combined deamination) is changed to the general metabolism of amino acids (degradation of protein in vivo, oxidative deamination, transamination and combined deamination), which should be reviewed.

　　Protein is composed of C (carbon), H (hydrogen), O (oxygen) and N (nitrogen). Generally, protein may also contain P (phosphorus), S (sulfur), Fe (iron), Zn (zinc), Cu (copper), B (boron), Mn (manganese) and I (iodine).The industry believes that, Antibody Discovery The development of our company marks the rapid and steady progress of the whole industry. https://www.alphalifetech.com/

　　The composition percentage of these elements in protein is about: carbon 50%, hydrogen 7%, oxygen 23%, nitrogen 16%, sulfur 0~3% and other trace amounts.

　　(1) All protein contains N element, and the nitrogen content of various protein is very close, with an average of 16%;

　　(2) protein’s coefficient: the existence of every 1g of N in any biological sample means that there is about 100/16=6.25g of protein, and 6.25 is often called protein’s constant.

　　(3) protein is a biopolymer based on amino acids. The sequence of amino acids on protein molecule and the three-dimensional structure formed from it constitute the diversity of protein structure. Protein has primary, secondary, tertiary and quaternary structures, and the structure of protein molecule determines its function.

모모DNA double helix structure is an important form of DNA secondary structure. It is a structural model put forward by Watson and Crick in 1953.Only by working together can we turn small molecules The value of the play out, the development of the supply market needs. https://www.all-chemistry.com/

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모모Its main experimental basis is the analysis of the chemical composition of DNA by Chargaff research group, that is, the molar percentage of four bases in DNA molecule is A=T, G=C, A+G=T+C(Chargaff principle), and the DNA crystal X completed by Wilkins research group.

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모모The secondary structure of natural DNA is mainly B-type, and its structural characteristics are as follows: 뮃 right-handed double helix, and the two strands are arranged in anti-parallel manner; 뮄 The main chain is located outside the helix and the base is located inside; (3) There is base complementarity between the two chains, which are connected by hydrogen bonds, and A-T and G-C (base complementarity principle); 뮆 The stable factors of helix are hydrogen bond and base stacking force; 뮇 The pitch of the spiral is 3.4nm and the diameter is 2nm.

　　Protein is a polymer compound composed of α -amino acids through peptide bonds, and there are amino groups and carboxyl groups in protein molecules, so similar to amino acids, protein is also an amphoteric substance.Without exception, Antibody Phage Display Service Our customers are willing to purchase their products, because high quality is the concept of their products. https://www.alphalifetech.com/

　　(1) Hydrolysis reaction

　　Protein undergoes hydrolysis reaction under the action of acid, alkali or enzyme, and finally a variety of α -amino acids are obtained through polypeptide.

　　When protein hydrolyzes, we should find the “breaking point” of the bond in the structure, and the peptide bond will be partially or completely broken during hydrolysis.

　　(2) Colloidal properties

　　Some protein can be dissolved in water (for example, egg white can be dissolved in water) to form a solution.

　　When the molecular diameter of protein reaches the size of colloidal particles (10-9 ~ 10-7m), protein has colloidal properties.

　　(3) precipitation

　　Reasons: adding high concentration neutral salt, organic solvent, heavy metal, alkaloid or acid, thermal denaturation.

　　A small amount of salt (such as ammonium sulfate, sodium sulfate, etc.) can promote the dissolution of protein. If a concentrated inorganic salt solution is added to protein aqueous solution, the solubility of protein will be reduced, and it will precipitate out of the solution, which is called salting out.

　　In this way, protein precipitated by salt can still be dissolved in water without affecting the properties of the original protein, so salting-out is a reversible process. Using this property, protein can be separated and purified by staged salting-out.

　　(4) degeneration

　　Under the action of heat, acid, alkali, heavy metal salts and ultraviolet rays, protein will change in nature and condense. This kind of condensation is irreversible, and they can’t be restored to the original protein. This change in protein is called transsexuality. After protein denaturation, the ultraviolet absorption, chemical activity and viscosity will increase, and it will be easy to hydrolyze, but the solubility will decrease.

　　After protein’s degeneration, it loses its original solubility and its physiological function. Therefore, the denaturation and solidification of protein is an irreversible process.

　　Life is a fleeting moment in the river of time, mankind do everything possible to seek forever and everlasting, but did not think, in fact, as long as the pace of their own slow down mentality flat, live in the present, then life will naturally become long and distant .Even if there are obstacles to moving forward, pu-erh tea We should also persevere, forge ahead bravely, cut waves in the sea of the market, hang on to Yun Fan and strive for the first place.

　　When I did not write a magazine before, I did not know that the time had come in advance. A draft of March or even April has been prepared in January. In the draft of the forum while watching the side gripped, his year has not yet ended, did not make a point, there people work has been a year, almost equal to the end. Years here, was actually can not wait to catch up with the speed of flight, how to make people panic?

　　The length of time is defined by man himself. 365 days a year, divided into four seasons, twelve months. Here, people always catch up with me like the game, to see who can one day into a day. Our ancestors know, if the decade into a year, we will so impatient it?

　　Days not used, can only be used to recover. Self has no intention to enter this door, it fell into such a turbulent swirl. Calendars and clocks on the numbers can only represent the past, because today to do, is already the future. Obviously is the spring, but the men have been doing non-stop fall thing.

　　There is nothing worthy of gratification, no reason for youth just a short length of a bit like others. What is the use of walking in front, time falls behind, urging the old soul and face it in vain.

　　The fast pace of modern people, nothing more than to speed up the clock of life, their own pressure and persecution of a way, only to more fully squeeze the juice of life to obtain value and fame. But I see it is faster and more leave no room for the consumption and flight. How, a ton of gold can be exchanged for even a second time?

　　Americans always run in front of the world, even spend today are tomorrow, the result? The financial crisis has finally shattered this myth of early consumption, punish all activities contrary to the laws of nature.

　　Beijing, then, a little leisurely. People live I, a spring vegetation, how short and beautiful time. If you can walk, why should anxious to run, miss the scenery all the way? Note that the front is not another spring, but has been waiting for you to close the end of life.

　　Tomorrow’s thing is done today, and next year’s event is finished this year. So ahead of the outstanding achievements and efforts, but is a result of the advance of life.

　　What is a rivers and lakes years reminder, juvenile children rivers and lakes old? This is the helplessness of life rather than enjoyment.