1.
Immunity (medical)
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Immunity is the capability of multicellular organisms to resist harmful microorganisms from entering it. Immunity involves both specific and nonspecific components, the nonspecific components act as barriers or eliminators of a wide range of pathogens irrespective of their antigenic make-up. Other components of the immune system adapt themselves to each new disease encountered and are able to generate pathogen-specific immunity, an immune system may contain innate and adaptive components. The innate system in mammalians for example is composed of bone marrow cells that are programmed to recognise foreign substances. The adaptive system is composed of more advanced lymphatic cells that are programmed to recognise self substances, the reaction to foreign substances is etymologically described as inflammation, meaning to set on fire. The non-reaction to self substances is described as immunity, meaning to exempt or as immunotolerance, disease can arise when what is foreign cannot be eliminated or what is self is not spared. Innate immunity, also called native immunity, exists by virtue of an organisms constitution and it is divided into two types, Non-Specific innate immunity, a degree of resistance to all infections in general. Specific innate immunity, a resistance to a kind of microorganism only. As a result some races, specific individuals or breeds in agriculture do not suffer from certain infectious diseases, passive immunity is acquired through transfer of antibodies or activated T-cells from an immune host, it is short lived—usually lasting only a few months. The diagram below summarizes these divisions of immunity, humoral immunity is called active when the organism generates its own antibodies, and passive when antibodies are transferred between individuals or species. Similarly, cell mediated immunity is active when the organisms’ own T-cells are stimulated, the concept of immunity has intrigued mankind for thousands of years. Between the time of Hippocrates and the 19th century, when the foundations of the methods were laid. If someone were exposed to the miasma in a swamp, in evening air, or breathing air in a sickroom or hospital ward, the modern word immunity derives from the Latin immunis, meaning exemption from military service, tax payments or other public services. For no one was attacked a second time, or not with a fatal result. The term immunes, is found in the epic poem Pharsalia written around 60 B. C. by the poet Marcus Annaeus Lucanus to describe a North African tribes resistance to snake venom. In the treatise, Al Razi describes the presentation of smallpox. The first scientist who developed full theory of immunity was Ilya Mechnikov after he revealed phagocytosis in 1882, the birth of active immunotherapy may have begun with Mithridates VI of Pontus. To induce active immunity for snake venom, he recommended using a similar to modern toxoid serum therapy
2.
Agglutination (biology)
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Agglutination is the clumping of particles. The word agglutination comes from the Latin agglutinare, agglutination occurs if an antigen is mixed with its corresponding antibody called isoagglutinin. This term is used in blood grouping. This occurs in biology in three main examples, The clumping of cells such as bacteria or red blood cells in the presence of an antibody or complement, the antibody or other molecule binds multiple particles and joins them, creating a large complex. This increases the efficacy of microbial elimination by phagocytosis as large clumps of bacteria can be eliminated in one pass, the coalescing of small particles that are suspended in a solution, these larger masses are then precipitated. Hemagglutination is the process by which red blood cells agglutinate, meaning clump or clog, the agglutin involved in hemagglutination is called hemagglutinin. In cross-matching, donor red blood cells and recipients serum or plasma are incubated together, if agglutination occurs, this indicates that the donor and recipient blood types are incompatible. Leukoagglutination is when the involved are white blood cells. An example is the PH-L form of phytohaemagglutinin, agglutination is commonly used as a method of identifying specific bacterial antigens, and in turn, the identity of such bacteria. Because the clumping reaction occurs quickly and is easy to produce, two bacteriologists, Herbert Edward Durham and Max von Gruber, discovered specific agglutination in 1896. The clumping became known as Gruber-Durham reaction, Gruber introduced the term agglutinin for any substance that caused agglutination of cells. French physician Fernand Widal put Gruber and Durhams discovery to practical use later in 1896, Widal found that blood serum from a typhoid carrier caused a culture of typhoid bacteria to clump, whereas serum from a typhoid-free person did not. This Widal test was the first example of serum diagnosis, austrian physician Karl Landsteiner found another important practical application of the agglutination reaction in 1900. Landsteiners agglutination tests and his discovery of ABO blood groups was the start of the science of blood transfusion and serology which has made transfusion possible, macrophage Immune System Blocking antibody Mannan Oligosaccharides Agglutination-PCR
3.
Immunoprecipitation
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Immunoprecipitation is the technique of precipitating a protein antigen out of solution using an antibody that specifically binds to that particular protein. This process can be used to isolate and concentrate a particular protein from a sample containing many thousands of different proteins, Immunoprecipitation requires that the antibody be coupled to a solid substrate at some point in the procedure. Involves using an antibody that is specific for a protein to isolate that particular protein out of a solution containing many different proteins. These solutions will often be in the form of a crude lysate of a plant or animal tissue, other sample types could be body fluids or other samples of biological origin. Immunoprecipitation of intact protein complexes is known as co-immunoprecipitation, co-IP works by selecting an antibody that targets a known protein that is believed to be a member of a larger complex of proteins. By targeting this known member with an antibody it may become possible to pull the protein complex out of solution. This concept of pulling protein complexes out of solution is sometimes referred to as a pull-down, co-IP is a powerful technique that is used regularly by molecular biologists to analyze protein–protein interactions. A particular antibody often selects for a subpopulation of its target protein that has the epitope exposed, thus failing to identify any proteins in complexes that hide the epitope. This can be seen in that it is possible to precipitate even half of a given protein from a sample with a single antibody. The first round that were not identified in the previous experiment, as successive rounds of targeting and immunoprecipitations take place, the number of identified proteins may continue to grow. The identified proteins may not ever exist in a complex at a given time. Repeating the experiment by targeting different members of the complex allows the researcher to double-check the result. Each round of pull-downs should result in the recovery of both the known protein as well as other previously identified members of the complex. By repeating the immunoprecipitation in this way, the researcher verifies that each identified member of the complex was a valid identification. Chromatin immunoprecipitation is a used to determine the location of DNA binding sites on the genome for a particular protein of interest. This technique gives a picture of the interactions that occur inside the nucleus of living cells or tissues. The in vivo nature of this method is in contrast to other approaches traditionally employed to answer the same questions, the principle underpinning this assay is that DNA-binding proteins in living cells can be cross-linked to the DNA that they are binding. By using an antibody that is specific to a putative DNA binding protein, the crosslinking is often accomplished by applying formaldehyde to the cells, although it is sometimes advantageous to use a more defined and consistent crosslinker such as DTBP
4.
Immunologist
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Immunology is a branch of biology that covers the study of immune systems in all organisms. It was the Russian biologist Ilya Ilyich Mechnikov who boosted studies on immunology and he jabbed the thorn of a rose on a starfish and noted that,24 hours later, cells were surrounding the tip. It was a response of the body, trying to maintain its integrity. It was Mechnikov who first observed the phenomenon of phagocytosis, in which the body defends itself against a foreign body, Immunology has applications in numerous disciplines of medicine, particularly in the fields of organ transplantation, oncology, virology, bacteriology, parasitology, psychiatry, and dermatology. The important lymphoid organs of the system are the thymus and bone marrow, and chief lymphatic tissues such as spleen, tonsils, lymph vessels, lymph nodes, adenoids. Classical immunology ties in with the fields of epidemiology and medicine and it studies the relationship between the body systems, pathogens, and immunity. The earliest written mention of immunity can be traced back to the plague of Athens in 430 BCE, thucydides noted that people who had recovered from a previous bout of the disease could nurse the sick without contracting the illness a second time. Many other ancient societies have references to this phenomenon, but it was not until the 19th and 20th centuries before the concept developed into scientific theory. The study of the molecular and cellular components that comprise the immune system, the immune system has been divided into a more primitive innate immune system and, in vertebrates, an acquired or adaptive immune system. The latter is divided into humoral and cell-mediated components. The humoral response is defined as the interaction between antibodies and antigens, antibodies are specific proteins released from a certain class of immune cells known as B lymphocytes, while antigens are defined as anything that elicits the generation of antibodies. Immunology rests on an understanding of the properties of two biological entities and the cellular response to both. Immunological research continues to more specialized, pursuing non-classical models of immunity and functions of cells, organs. Clinical immunology is the study of diseases caused by disorders of the immune system and it also involves diseases of other systems, where immune reactions play a part in the pathology and clinical features. Other immune system include various hypersensitivities that respond inappropriately to otherwise harmless compounds. Clinical immunologists also study ways to prevent the immune systems attempts to destroy allografts, the body’s capability to react to antigen depends on a persons age, antigen type, maternal factors and the area where the antigen is presented. Neonates are said to be in a state of physiological immunodeficiency, once born, a child’s immune system responds favorably to protein antigens while not as well to glycoproteins and polysaccharides. In fact, many of the infections acquired by neonates are caused by low virulence organisms like Staphylococcus, in neonates, opsonic activity and the ability to activate the complement cascade is very limited
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Biochemistry
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Biochemistry, sometimes called biological chemistry, is the study of chemical processes within and relating to living organisms. By controlling information flow through biochemical signaling and the flow of energy through metabolism. Biochemistry is closely related to biology, the study of the molecular mechanisms by which genetic information encoded in DNA is able to result in the processes of life. Depending on the definition of the terms used, molecular biology can be thought of as a branch of biochemistry, or biochemistry as a tool with which to investigate. The chemistry of the cell depends on the reactions of smaller molecules. These can be inorganic, for water and metal ions, or organic, for example the amino acids. The mechanisms by which cells harness energy from their environment via chemical reactions are known as metabolism, the findings of biochemistry are applied primarily in medicine, nutrition, and agriculture. In medicine, biochemists investigate the causes and cures of diseases, in nutrition, they study how to maintain health and study the effects of nutritional deficiencies. In agriculture, biochemists investigate soil and fertilizers, and try to discover ways to improve crop cultivation, crop storage and pest control. However, biochemistry as a scientific discipline has its beginning sometime in the 19th century, or a little earlier. Gowland Hopkins on enzymes and the nature of biochemistry. The term biochemistry itself is derived from a combination of biology, the German chemist Carl Neuberg however is often cited to have coined the word in 1903, while some credited it to Franz Hofmeister. Then, in 1828, Friedrich Wöhler published a paper on the synthesis of urea and these techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle. Another significant historic event in biochemistry is the discovery of the gene and this part of biochemistry is often called molecular biology. In the 1950s, James D. Watson, Francis Crick, Rosalind Franklin, in 1958, George Beadle and Edward Tatum received the Nobel Prize for work in fungi showing that one gene produces one enzyme. In 1988, Colin Pitchfork was the first person convicted of murder with DNA evidence, mello received the 2006 Nobel Prize for discovering the role of RNA interference, in the silencing of gene expression. Around two dozen of the 92 naturally occurring elements are essential to various kinds of biological life. Most rare elements on Earth are not needed by life, while a few common ones are not used, most organisms share element needs, but there are a few differences between plants and animals
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Biomolecule
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A more general name for this class of material is biological materials. Biomolecules are usually endogenous but may also be exogenous, for example, pharmaceutical drugs may be natural products or semisynthetic or they may be totally synthetic. Biology and its subsets of biochemistry and molecular biology study biomolecules, most biomolecules are organic compounds, and just four elements—oxygen, carbon, hydrogen, and nitrogen—make up 96% of the human bodys mass. But many other elements, such as the various biometals, are present in small amounts, examples of these include cytidine, uridine, adenosine, guanosine, thymidine and inosine. Nucleosides can be phosphorylated by specific kinases in the cell, producing nucleotides, both DNA and RNA are polymers, consisting of long, linear molecules assembled by polymerase enzymes from repeating structural units, or monomers, of mononucleotides. DNA uses the deoxynucleotides C, G, A, and T, while RNA uses the ribonucleotides C, G, A, modified bases are fairly common, as found in ribosomal RNA or transfer RNAs or for discriminating the new from old strands of DNA after replication. Each nucleotide is made of a nitrogenous base, a pentose. They contain carbon, nitrogen, oxygen, hydrogen and phosphorus and they serve as sources of chemical energy, participate in cellular signaling, and are incorporated into important cofactors of enzymatic reactions. DNA structure is dominated by the double helix formed by Watson-Crick base-pairing of C with G and A with T. This is known as B-form DNA, and is overwhelmingly the most favorable and common state of DNA, its highly specific and stable base-pairing is the basis of reliable genetic information storage. DNA can sometimes occur as single strands or as A-form or Z-form helices, RNA, in contrast, forms large and complex 3D tertiary structures reminiscent of proteins, as well as the loose single strands with locally folded regions that constitute messenger RNA molecules. Those RNA structures contain many stretches of A-form double helix, connected into definite 3D arrangements by single-stranded loops, bulges, examples are tRNA, ribosomes, ribozymes, and riboswitches. Monosaccharides are the simplest form of carbohydrates with only one simple sugar and they essentially contain an aldehyde or ketone group in their structure. The presence of an group in a monosaccharide is indicated by the prefix aldo-. Similarly, a group is denoted by the prefix keto-. Examples of monosaccharides are the hexoses glucose, fructose, and galactose and pentoses, ribose, most saccharides eventually provide fuel for cellular respiration. Disaccharides are formed when two monosaccharides, or two simple sugars, form a bond with removal of water. They can be hydrolyzed to yield their saccharin building blocks by boiling with dilute acid or reacting them with appropriate enzymes, examples of disaccharides include sucrose, maltose, and lactose
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Metabolism
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Metabolism is the set of life-sustaining chemical transformations within the cells of living organisms. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, usually, breaking down releases energy and building up consumes energy. The chemical reactions of metabolism are organized into metabolic pathways, in one chemical is transformed through a series of steps into another chemical. Enzymes act as catalysts that allow the reactions to proceed more rapidly, enzymes also allow the regulation of metabolic pathways in response to changes in the cells environment or to signals from other cells. The metabolic system of a particular organism determines which substances it will find nutritious, for example, some prokaryotes use hydrogen sulfide as a nutrient, yet this gas is poisonous to animals. The speed of metabolism, the rate, influences how much food an organism will require. A striking feature of metabolism is the similarity of the metabolic pathways. These striking similarities in metabolic pathways are likely due to their appearance in evolutionary history. Most of the structures that make up animals, plants and microbes are made from three classes of molecule, amino acids, carbohydrates and lipids. These biochemicals can be joined together to make such as DNA and proteins. Proteins are made of amino acids arranged in a linear chain joined together by peptide bonds, many proteins are enzymes that catalyze the chemical reactions in metabolism. Other proteins have structural or mechanical functions, such as those that form the cytoskeleton, Proteins are also important in cell signaling, immune responses, cell adhesion, active transport across membranes, and the cell cycle. Lipids are the most diverse group of biochemicals and their main structural uses are as part of biological membranes both internal and external, such as the cell membrane, or as a source of energy. Lipids are usually defined as hydrophobic or amphipathic biological molecules but will dissolve in organic solvents such as benzene or chloroform, the fats are a large group of compounds that contain fatty acids and glycerol, a glycerol molecule attached to three fatty acid esters is called a triacylglyceride. Several variations on this structure exist, including alternate backbones such as sphingosine in the sphingolipids. Steroids such as cholesterol are another class of lipids. Carbohydrates are aldehydes or ketones, with hydroxyl groups attached. Carbohydrates are the most abundant biological molecules, and fill numerous roles, such as the storage and transport of energy, the basic carbohydrate units are called monosaccharides and include galactose, fructose, and most importantly glucose
8.
History of biochemistry
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The term “biochemistry” itself is derived from the combining form bio-, meaning life, and chemistry. Nevertheless, several sources cite German chemist Carl Neuberg as having coined the term for the new discipline in 1903, and some credit it to Franz Hofmeister. Over the last 40 years the field has had success in explaining living processes such that now almost all areas of the life sciences from botany to medicine are engaged in biochemical research. Among the vast number of different biomolecules, many are complex and large molecules, each class of polymeric biomolecule has a different set of subunit types. Biochemistry studies the properties of important biological molecules, like proteins. The biochemistry of cell metabolism and the system has been extensively described. Other areas of biochemistry include the code, protein synthesis, cell membrane transport. It began in the ancient Indian culture also with an interest in medicine and they also delved into the interest of bodies being composed of tissues. On the side of chemistry, early advancements were heavily attributed to exploration of interests but also included, metallurgy, the scientific method. In more recent times, the study of chemistry was marked by such as the development of Mendeleevs periodic table, Daltons atomic model. This last mention has the most importance of the three due to the fact that this law intertwines chemistry with thermodynamics in an intercalated manner. As early as the late 18th century and early 19th century, the digestion of meat by stomach secretions, however, the mechanism by which this occurred had not been identified. He wrote that alcoholic fermentation is an act correlated with the life and organization of the yeast cells, the word enzyme was used later to refer to nonliving substances such as pepsin, and the word ferment used to refer to chemical activity produced by living organisms. In 1897 Eduard Buchner began to study the ability of yeast extracts to ferment sugar despite the absence of living yeast cells. In a series of experiments at the University of Berlin, he found that the sugar was fermented even when there were no living yeast cells in the mixture and he named the enzyme that brought about the fermentation of sucrose zymase. In 1907 he received the Nobel Prize in Chemistry for his biochemical research, following Buchners example, enzymes are usually named according to the reaction they carry out. Typically the suffix -ase is added to the name of the substrate or the type of reaction, having shown that enzymes could function outside a living cell, the next step was to determine their biochemical nature. Sumner showed that the enzyme urease was a protein and crystallized it
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Cell biology
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Cell biology is a branch of biology that studies the different structures and functions of the cell and focuses mainly on the idea of the cell as the basic unit of life. This is done both on a microscopic and molecular level as it encompasses prokaryotic cells and eukaryotic cells, knowing the components of cells and how cells work is fundamental to all biological sciences, it is also essential for research in bio-medical fields such as cancer, and other diseases. Research in cell biology is closely related to genetics, biochemistry, molecular biology, immunology, and developmental biology. The study of the cell is done on a level, however, most of the processes within the cell are made up of a mixture of small organic molecules, inorganic ions, hormones. Approximately 75-85% of the volume is due to water making it an indispensable solvent as a result of its polarity. These molecules within the cell, which operate as substrates, provide an environment for the cell to carry out metabolic reactions. The cell shape varies among the different types of organisms, and are then classified into two categories, eukaryotes and prokaryotes. Cell biology focuses more on the study of cells, and their signalling pathways. This environment of the cell is made up of hydrophilic and hydrophobic regions which allows for the exchange of the above-mentioned molecules and ions. The hydrophilic regions of the cell are mainly on the inside and outside of the cell, the cell membrane consists of lipids and proteins which accounts for its hydrophobicity as a result of being non-polar substances. Therefore, in order for these molecules to participate in reactions, within the cell and they accomplish this process of gaining access to the cell via, osmotic pressure, diffusion, concentration gradients, and membrane channels. Inside of the cell are extensive internal sub-cellular membrane-bounded compartments called organelles, cytoplasm - contents of the main fluid-filled space inside cells, chemical reactions also happen in this jelly-like substance. Nuclear Architecture is important for dictating nuclear function, vacuole - contain cell sap or other storage material. Vesicle - small membrane-bounded spheres inside cells which transport substances, the growth process of the cell does not refer to the size of the cell, but instead the density of the number of cells present in the organism at a given time. Cell growth pertains to the increase in the number of cells present in an organism as it grows and develops, Cells are the foundation of all organisms, they are the fundamental unit of life. The growth and development of the cell are essential for the maintenance of the host, for this process the cell goes through the steps of the cell cycle and development which involves cell growth, DNA replication, cell division, regeneration, specialization, and cell death. The cell cycle is divided into four phases, G1, S, G2. The G phases – which is the growth phase - makes up approximately 95% of the cycle
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Bioinformatics
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Bioinformatics /ˌbaɪ. oʊˌɪnfərˈmætɪks/ is an interdisciplinary field that develops methods and software tools for understanding biological data. As an interdisciplinary field of science, bioinformatics combines computer science, statistics, mathematics, Bioinformatics has been used for in silico analyses of biological queries using mathematical and statistical techniques. Common uses of bioinformatics include the identification of genes and nucleotides. Often, such identification is made with the aim of understanding the genetic basis of disease, unique adaptations, desirable properties. In a less formal way, bioinformatics also tries to understand the principles within nucleic acid and protein sequences. Bioinformatics has become an important part of areas of biology. In experimental molecular biology, bioinformatics techniques such as image and signal processing allow extraction of useful results from large amounts of raw data, in the field of genetics and genomics, it aids in sequencing and annotating genomes and their observed mutations. It plays a role in the mining of biological literature. It also plays a role in the analysis of gene and protein expression and regulation, Bioinformatics tools aid in the comparison of genetic and genomic data and more generally in the understanding of evolutionary aspects of molecular biology. At a more level, it helps analyze and catalogue the biological pathways. In structural biology, it aids in the simulation and modeling of DNA, RNA, historically, the term bioinformatics did not mean what it means today. Paulien Hogeweg and Ben Hesper coined it in 1970 to refer to the study of processes in biotic systems. This definition placed bioinformatics as a parallel to biophysics or biochemistry. Computers became essential in molecular biology when protein sequences became available after Frederick Sanger determined the sequence of insulin in the early 1950s, comparing multiple sequences manually turned out to be impractical. A pioneer in the field was Margaret Oakley Dayhoff, who has been hailed by David Lipman, director of the National Center for Biotechnology Information, Dayhoff compiled one of the first protein sequence databases, initially published as books and pioneered methods of sequence alignment and molecular evolution. To study how normal cellular activities are altered in different disease states, therefore, the field of bioinformatics has evolved such that the most pressing task now involves the analysis and interpretation of various types of data. This includes nucleotide and amino acid sequences, protein domains, the actual process of analyzing and interpreting data is referred to as computational biology. For example, there are methods to locate a gene within a sequence, to predict protein structure and/or function, the primary goal of bioinformatics is to increase the understanding of biological processes
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Enzyme
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Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. Enzymes accelerate, or catalyze, chemical reactions, the molecules at the beginning of the process upon which enzymes may act are called substrates and the enzyme converts these into different molecules, called products. Almost all metabolic processes in the cell need enzymes in order to occur at rates fast enough to sustain life, the set of enzymes made in a cell determines which metabolic pathways occur in that cell. The study of enzymes is called enzymology, enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins, although a few are catalytic RNA molecules, enzymes specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the rate of a reaction by lowering its activation energy, some enzymes can make their conversion of substrate to product occur many millions of times faster. An extreme example is orotidine 5-phosphate decarboxylase, which allows a reaction that would take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules, inhibitors are molecules that decrease enzyme activity, many drugs and poisons are enzyme inhibitors. An enzymes activity decreases markedly outside its optimal temperature and pH, some enzymes are used commercially, for example, in the synthesis of antibiotics. French chemist Anselme Payen was the first to discover an enzyme, diastase and he wrote that alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells. In 1877, German physiologist Wilhelm Kühne first used the term enzyme, the word enzyme was used later to refer to nonliving substances such as pepsin, and the word ferment was used to refer to chemical activity produced by living organisms. Eduard Buchner submitted his first paper on the study of yeast extracts in 1897, in a series of experiments at the University of Berlin, he found that sugar was fermented by yeast extracts even when there were no living yeast cells in the mixture. He named the enzyme that brought about the fermentation of sucrose zymase, in 1907, he received the Nobel Prize in Chemistry for his discovery of cell-free fermentation. Following Buchners example, enzymes are usually named according to the reaction they carry out, the biochemical identity of enzymes was still unknown in the early 1900s. Sumner showed that the enzyme urease was a protein and crystallized it. These three scientists were awarded the 1946 Nobel Prize in Chemistry, the discovery that enzymes could be crystallized eventually allowed their structures to be solved by x-ray crystallography. This high-resolution structure of lysozyme marked the beginning of the field of structural biology, an enzymes name is often derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase
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Genetics
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Genetics is the study of genes, genetic variation, and heredity in living organisms. It is generally considered a field of biology, but intersects frequently with other life sciences and is strongly linked with the study of information systems. The father of genetics is Gregor Mendel, a late 19th-century scientist, Mendel studied trait inheritance, patterns in the way traits are handed down from parents to offspring. He observed that organisms inherit traits by way of discrete units of inheritance and this term, still used today, is a somewhat ambiguous definition of what is referred to as a gene. Gene structure and function, variation, and distribution are studied within the context of the cell, the organism, genetics has given rise to a number of subfields, including epigenetics and population genetics. Organisms studied within the broad field span the domain of life, including bacteria, plants, animals, genetic processes work in combination with an organisms environment and experiences to influence development and behavior, often referred to as nature versus nurture. The intracellular or extracellular environment of a cell or organism may switch gene transcription on or off, a classic example is two seeds of genetically identical corn, one placed in a temperate climate and one in an arid climate. The word genetics stems from the ancient Greek γενετικός genetikos meaning genitive/generative, the observation that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding. The modern science of genetics, seeking to understand this process, prior to Mendel, Imre Festetics, a Hungarian noble, who lived in Kőszeg before Mendel, was the first who used the word genetics. He described several rules of inheritance in his work The genetic law of the Nature. His second law is the same as what Mendel published, in his third law, he developed the basic principles of mutation. Other theories of inheritance preceded his work, a popular theory during Mendels time was the concept of blending inheritance, the idea that individuals inherit a smooth blend of traits from their parents. Mendels work provided examples where traits were not blended after hybridization. Blending of traits in the progeny is now explained by the action of genes with quantitative effects. Another theory that had some support at that time was the inheritance of acquired characteristics, other theories included the pangenesis of Charles Darwin and Francis Galtons reformulation of pangenesis as both particulate and inherited. Modern genetics started with Gregor Johann Mendel, a scientist and Augustinian friar who studied the nature of inheritance in plants, the importance of Mendels work did not gain wide understanding until the 1890s, after his death, when other scientists working on similar problems re-discovered his research. William Bateson, a proponent of Mendels work, coined the word genetics in 1905, Bateson popularized the usage of the word genetics to describe the study of inheritance in his inaugural address to the Third International Conference on Plant Hybridization in London in 1906. After the rediscovery of Mendels work, scientists tried to determine which molecules in the cell were responsible for inheritance, in 1911, Thomas Hunt Morgan argued that genes are on chromosomes, based on observations of a sex-linked white eye mutation in fruit flies
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Molecular biology
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Writing in Nature in 1961, William Astbury described molecular biology as. It is concerned particularly with the forms of biological molecules and is predominantly three-dimensional and structural—which does not mean, however and it must at the same time inquire into genesis and function. Researchers in molecular biology use specific techniques native to molecular biology but increasingly combine these techniques and ideas from genetics. There is not a line between these disciplines. Biochemists focus heavily on the role, function, and structure of biomolecules, the study of the chemistry behind biological processes and the synthesis of biologically active molecules are examples of biochemistry. Genetics is the study of the effect of differences on organisms. This can often be inferred by the absence of a normal component, the study of mutants – organisms which lack one or more functional components with respect to the so-called wild type or normal phenotype. Genetic interactions can often confound simple interpretations of such knockout studies, molecular biology is the study of molecular underpinnings of the processes of replication, transcription, translation, and cell function. This picture, however, is undergoing revision in light of emerging novel roles for RNA, much of molecular biology is quantitative, and recently much work has been done at its interface with computer science in bioinformatics and computational biology. In the early 2000s, the study of structure and function. There is also a tradition of studying biomolecules from the ground up in biophysics. One of the most basic techniques of molecular biology to study protein function is molecular cloning, in this technique, DNA coding for a protein of interest is cloned using PCR and/or restriction enzymes into a plasmid. A vector has 3 distinctive features, an origin of replication, a multiple cloning site, the origin of replication will have promoter regions upstream from the replication/transcription start site. This plasmid can be inserted into either bacterial or animal cells, introducing DNA into bacterial cells can be done by transformation via uptake of naked DNA, conjugation via cell-cell contact or by transduction via viral vector. Introducing DNA into eukaryotic cells, such as cells, by physical or chemical means is called transfection. Several different transfection techniques are available, such as calcium phosphate transfection, electroporation, microinjection, the plasmid may be integrated into the genome, resulting in a stable transfection, or may remain independent of the genome, called transient transfection. DNA coding for a protein of interest is now inside a cell, a variety of systems, such as inducible promoters and specific cell-signaling factors, are available to help express the protein of interest at high levels. Large quantities of a protein can then be extracted from the bacterial or eukaryotic cell, polymerase chain reaction is an extremely versatile technique for copying DNA
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Structural biology
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This architecture, the tertiary structure of molecules, depends in a complicated way on the molecules basic composition, or primary structures. Biomolecules are too small to see in detail even with the most advanced light microscopes, the methods that structural biologists use to determine their structures generally involve measurements on vast numbers of identical molecules at the same time. But variations on these methods are used to watch nascent or denatured molecules assume or reassume their native states. A third approach that structural biologists take to understanding structure is bioinformatics to look for patterns among the sequences that give rise to particular shapes. Researchers often can deduce aspects of the structure of membrane proteins based on the membrane topology predicted by hydrophobicity analysis. In the past few years it has become possible for highly accurate physical models to complement the in silico study of biological structures. Examples of these models can be found in the Protein Data Bank
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Glossary of chemistry terms
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This page is a glossary of chemistry terms. Chemistry has a vocabulary and a significant amount of jargon. This is a list of terms, including laboratory tools, glassware. Chemistry itself is a science concerned with the composition, structure. It represents 1 mol of electrons, or the Avogadro number of electrons,6.022 ×1023 electrons, ficks laws of diffusion - frequency – number of cycles per unit of time. 023X10^23 atoms group – the elements in a column of the periodic table. Jodium – Latin name of the element iodine Joule – The SI unit of energy. Kelvin – A unit of measure for temperature based upon an absolute scale, lanthanides – Elements 57 through 71 lattice – Unique arrangement of atoms or molecules in a crystalline liquid or solid. Laws of thermodynamics Lewis acid - Lewis base - liquid – A state of matter in which force is less than or equal to the separating force. Light – Portion of the spectrum which is visible to the naked eye. London dispersion forces – A weak intermolecular force laws of motion – An object in motion stays in motion, magnetic quantum number - manometer - Instrument to measure pressure, invented by Evangelista Torricelli in 1643. It is made up of solutes and solvents, but there are some positive and negative charges in it, due to the formal charge, owing to the partial charges of its constituent atoms
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Biology
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Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, evolution, distribution, identification and taxonomy. Modern biology is a vast and eclectic field, composed of branches and subdisciplines. However, despite the broad scope of biology, there are certain unifying concepts within it that consolidate it into single, coherent field. In general, biology recognizes the cell as the unit of life, genes as the basic unit of heredity. It is also understood today that all organisms survive by consuming and transforming energy and by regulating their internal environment to maintain a stable, the term biology is derived from the Greek word βίος, bios, life and the suffix -λογία, -logia, study of. The Latin-language form of the term first appeared in 1736 when Swedish scientist Carl Linnaeus used biologi in his Bibliotheca botanica, the first German use, Biologie, was in a 1771 translation of Linnaeus work. In 1797, Theodor Georg August Roose used the term in the preface of a book, karl Friedrich Burdach used the term in 1800 in a more restricted sense of the study of human beings from a morphological, physiological and psychological perspective. The science that concerns itself with these objects we will indicate by the biology or the doctrine of life. Although modern biology is a recent development, sciences related to. Natural philosophy was studied as early as the ancient civilizations of Mesopotamia, Egypt, the Indian subcontinent, however, the origins of modern biology and its approach to the study of nature are most often traced back to ancient Greece. While the formal study of medicine back to Hippocrates, it was Aristotle who contributed most extensively to the development of biology. Especially important are his History of Animals and other works where he showed naturalist leanings, and later more empirical works that focused on biological causation and the diversity of life. Aristotles successor at the Lyceum, Theophrastus, wrote a series of books on botany that survived as the most important contribution of antiquity to the plant sciences, even into the Middle Ages. Scholars of the medieval Islamic world who wrote on biology included al-Jahiz, Al-Dīnawarī, who wrote on botany, biology began to quickly develop and grow with Anton van Leeuwenhoeks dramatic improvement of the microscope. It was then that scholars discovered spermatozoa, bacteria, infusoria, investigations by Jan Swammerdam led to new interest in entomology and helped to develop the basic techniques of microscopic dissection and staining. Advances in microscopy also had a impact on biological thinking. In the early 19th century, a number of biologists pointed to the importance of the cell. Thanks to the work of Robert Remak and Rudolf Virchow, however, meanwhile, taxonomy and classification became the focus of natural historians
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Immune system
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The immune system is a host defense system comprising many biological structures and processes within an organism that protects against disease. To function properly, a system must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms. In many species, the system can be classified into subsystems, such as the innate immune system versus the adaptive immune system. In humans, the barrier, blood–cerebrospinal fluid barrier, and similar fluid–brain barriers separate the peripheral immune system from the neuroimmune system. Even simple unicellular organisms such as bacteria possess a rudimentary immune system in the form of enzymes that protect against bacteriophage infections, other basic immune mechanisms evolved in ancient eukaryotes and remain in their modern descendants, such as plants and invertebrates. These mechanisms include phagocytosis, antimicrobial peptides called defensins, and the complement system, jawed vertebrates, including humans, have even more sophisticated defense mechanisms, including the ability to adapt over time to recognize specific pathogens more efficiently. Adaptive immunity creates immunological memory after a response to a specific pathogen. This process of acquired immunity is the basis of vaccination, disorders of the immune system can result in autoimmune diseases, inflammatory diseases and cancer. Immunodeficiency occurs when the system is less active than normal. In humans, immunodeficiency can either be the result of a disease such as severe combined immunodeficiency, acquired conditions such as HIV/AIDS. In contrast, autoimmunity results from an immune system attacking normal tissues as if they were foreign organisms. Common autoimmune diseases include Hashimotos thyroiditis, rheumatoid arthritis, diabetes mellitus type 1, immunology covers the study of all aspects of the immune system. Immunology is a science that examines the structure and function of the immune system and it originates from medicine and early studies on the causes of immunity to disease. The earliest known reference to immunity was during the plague of Athens in 430 BC, thucydides noted that people who had recovered from a previous bout of the disease could nurse the sick without contracting the illness a second time. In the 18th century, Pierre-Louis Moreau de Maupertuis made experiments with scorpion venom and observed that certain dogs and this and other observations of acquired immunity were later exploited by Louis Pasteur in his development of vaccination and his proposed germ theory of disease. Pasteurs theory was in opposition to contemporary theories of disease. It was not until Robert Kochs 1891 proofs, for which he was awarded a Nobel Prize in 1905, viruses were confirmed as human pathogens in 1901, with the discovery of the yellow fever virus by Walter Reed. Immunology made an advance towards the end of the 19th century, through rapid developments, in the study of humoral immunity
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Organism
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In biology, an organism is any contiguous living system, such as an animal, plant, fungus, protist, archaeon, or bacterium. All known types of organisms are capable of some degree of response to stimuli, reproduction, growth and development and homeostasis. An organism consists of one or more cells, when it has one cell it is known as an organism. Most unicellular organisms are of microscopic scale and are thus described as microorganisms. Humans are multicellular organisms composed of trillions of cells grouped into specialized tissues. An organism may be either a prokaryote or a eukaryote, prokaryotes are represented by two separate domains—bacteria and archaea. Eukaryotic organisms are characterized by the presence of a cell nucleus. Fungi, animals and plants are examples of kingdoms of organisms within the eukaryotes, estimates on the number of Earths current species range from 10 million to 14 million, of which only about 1.2 million have been documented. More than 99% of all species, amounting to five billion species. In 2016, a set of 355 genes from the last universal ancestor of all living organisms living was identified. The term organism first appeared in the English language in 1703 and it is directly related to the term organization. There is a tradition of defining organisms as self-organizing beings. An organism may be defined as an assembly of molecules functioning as a more or less stable whole that exhibits the properties of life. Dictionary definitions can be broad, using such as any living structure, such as a plant, animal, fungus or bacterium, capable of growth. Many definitions exclude viruses and possible man-made non-organic life forms, as viruses are dependent on the machinery of a host cell for reproduction. A superorganism is an organism consisting of individuals working together as a single functional or social unit. There has been controversy about the best way to define the organism, several contributions are responses to the suggestion that the category of organism may well not be adequate in biology. Viruses are not typically considered to be organisms because they are incapable of autonomous reproduction and this controversy is problematic because some cellular organisms are also incapable of independent survival and live as obligatory intracellular parasites
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Physiology
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Physiology is the scientific study of normal mechanisms, and their interactions, which operate within a living system. A sub-discipline of biology, its focus is in how organisms, organ systems, organs, cells, and biomolecules carry out the chemical or physical functions that exist in a living system. Given the size of the field, it is divided into, among others, animal physiology, plant physiology, cellular physiology, microbial physiology, bacterial physiology, and viral physiology. The Nobel Prize in Physiology or Medicine is awarded to those who make significant achievements in this discipline by the Royal Swedish Academy of Sciences. In medicine, a state is one occurring from normal body function, rather than pathologically. Physiological studies date back to the ancient civilizations of India and Egypt alongside anatomical studies, the study of human physiology as a medical field dates back to at least 420 BC to the time of Hippocrates, also known as the father of medicine. Hippocrates incorporated his belief called the theory of humours, which consisted of four basic substance, earth, water, air. Each substance is known for having a corresponding humour, black bile, phlegm, blood and yellow bile, Hippocrates also noted some emotional connections to the four humours, which Claudis Galenus would later expand on. The critical thinking of Aristotle and his emphasis on the relationship between structure and function marked the beginning of physiology in Ancient Greece. Like Hippocrates, Aristotle took to the theory of disease. Claudius Galenus, known as Galen of Pergamum, was the first to use experiments to probe the functions of the body, unlike Hippocrates though, Galen argued that humoral imbalances can be located in specific organs, including the entire body. His modification of this theory better equipped doctors to more precise diagnoses. Galen was also the founder of experimental physiology, and for the next 1,400 years, Galenic physiology was a powerful and influential tool in medicine. Jean Fernel, a French physician, introduced the term physiology, inspired in the work of Adam Smith, Milne-Edwards wrote that the body of all living beings, whether animal or plant, resembles a factory. Where the organs, comparable to workers, work incessantly to produce the phenomena that constitute the life of the individual, in more differentiated organisms, the functional labor could be apportioned between different instruments or systems. In 1858, Joseph Lister studied the cause of blood coagulation and inflammation that resulted after previous injuries and he later discovered and implemented antiseptics in the operating room, and as a result decreases death rate from surgery by a substantial amount. The Physiological Society was founded in London in 1876 as a dining club, the American Physiological Society is a nonprofit organization that was founded in 1887. The Society is, devoted to fostering education, scientific research, in 1891, Ivan Pavlov performed research on conditional reflexes that involved dogs saliva production in response to a plethora of sounds and visual stimuli
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In vitro
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In vitro studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. In contrast, in studies are those conducted in animals, including humans. In vitro studies are conducted using components of an organism that have been isolated from their biological surroundings, such as microorganisms, cells. For example, microrganisms or cells can be studied in artificial culture media, colloquially called test-tube experiments, these studies in biology, medicine, and their subdisciplines are traditionally done in test tubes, flasks, Petri dishes, etc. They now involve the range of techniques used in molecular biology. In contrast, studies conducted in living beings are called in vivo, polymerase chain reaction is a method for selective replication of specific DNA and RNA sequences in the test tube. Protein purification involves the isolation of a protein of interest from a complex mixture of proteins. In vitro fertilization is used to allow spermatozoa to fertilize eggs in a culture dish before implanting the resulting embryo or embryos into the uterus of the prospective mother and these ADME process parameters can then be integrated into so called physiologically based pharmacokinetic models or PBPK. In vitro studies permit a species-specific, simpler, more convenient, just as studies in whole animals more and more replace human trials, so are in vitro studies replacing studies in whole animals. This complexity makes it difficult to identify the interactions between individual components and to explore their basic biological functions, in vitro work simplifies the system under study, so the investigator can focus on a small number of components. Another advantage of in vitro methods is that cells can be studied without extrapolation from an experimental animals cellular response. Investigators doing in vitro work must be careful to avoid over-interpretation of their results, for example, scientists developing a new viral drug to treat an infection with a pathogenic virus may find that a candidate drug functions to prevent viral replication in an in vitro setting. However, before this drug is used in the clinic, it must progress through a series of in vivo trials to determine if it is safe and effective in intact organisms. Results obtained from in vitro experiments cannot usually be transposed, as is, building a consistent and reliable extrapolation procedure from in vitro results to in vivo is therefore extremely important. However, increasingly sophisticated in vitro experiments collect increasingly numerous, complex, mathematical models, such as systems biology models, are much needed here. In pharmacology, IVIVE can be used to approximate pharmacokinetics or pharmacodynamics and that indicates that extrapolating effects observed in vitro needs a quantitative model of in vivo PK. Physiologically based PK models are generally accepted to be central to the extrapolations, in these conditions, developing a simple PD model of the dose–response relationship observed in vitro, and transposing it without changes to predict in vivo effects is not enough
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In situ
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In situ is a Latin phrase that translates literally to on site or in position. It means locally, on site, on the premises or in place to describe an event where it takes place, in the aerospace industry, equipment on-board aircraft must be tested in situ, or in place, to confirm everything functions properly as a system. Individually, each piece may work but interference from nearby equipment may create unanticipated problems, special test equipment is available for this in situ testing. In archaeology, in situ refers to an artifact that has not been moved from its place of deposition. In other words, it is stationary, meaning still, an artifact being in situ is critical to the interpretation of that artifact and, consequently, of the culture which formed it. Once an artifacts find-site has been recorded, the artifact can then be moved for conservation, further interpretation, an artifact that is not discovered in situ is considered out of context and as not providing an accurate picture of the associated culture. However, the out of context artifact can provide scientists with an example of types, when excavating a burial site or surface deposit in situ refers to cataloging, recording, mapping, photographing human remains in the position they are discovered. The label in situ indicates only that the object has not been newly moved. Thus, an archaeological in situ find may be an object that was looted from another place, an item of booty of a past war. Consequently, the in situ find site may not reveal its provenance. It is also possible for archaeological layers to be reworked on purpose or by accident, for example, in a Tell mound, where layers are not typically uniform or horizontal, or in land cleared or tilled for farming. The term in situ is used to describe ancient sculpture that was carved in place such as the Sphinx or Petra. This distinguishes it from statues that were carved and moved like the Colossi of Memnon, which was moved in ancient times. In art, in situ refers to a work of art made specifically for a host site, for a more detailed account see, Site-specific art. The term can refer to a work of art created at the site where it is to be displayed, rather than one created in the artists studio. In architectural sculpture the term is employed to describe sculpture that is carved on a building, frequently from scaffolds. A fraction of the star clusters in our galaxy, as well as those in other massive galaxies. The rest might have been accreted from now defunct dwarf galaxies, in biology and biomedical engineering, in situ means to examine the phenomenon exactly in place where it occurs
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Phagocytosis
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In cell biology, phagocytosis is the process by which a cell—often a phagocyte or a protist—engulfs a solid particle to form an internal compartment known as a phagosome. It is distinct from other forms of endocytosis like pinocytosis that involves the internalization of extracellular liquids, phagocytosis is involved in the acquisition of nutrients for some cells. In an organisms immune system, phagocytosis is a mechanism used to remove pathogens. For example, when a macrophage ingests a pathogenic microorganism, the pathogen becomes trapped in a phagosome which then fuses with a lysosome to form a phagolysosome, within the phagolysosome, enzymes and toxic peroxides digest the pathogen. Bacteria, dead cells, and small mineral particles are all examples of objects that may be phagocytized. The process has triggered the name Phagocytes for the 1st line of defence in the immune system, phagocytosis was first noted by Canadian physician William Osler, and later studied and named by Élie Metchnikoff. Phagocytosis in mammalian cells is activated by attachment to pathogen-associated molecular patterns. Opsonins such as C3b and antibodies can act as attachment sites, engulfment of material is facilitated by the actin-myosin contractile system. The phagosome of ingested material is fused with the lysosome, forming a phagolysosome. Degradation can be oxygen-dependent or oxygen-independent, oxygen-dependent degradation depends on NADPH and the production of reactive oxygen species. Hydrogen peroxide and myeloperoxidase activate a system, which leads to the creation of hypochlorite. Oxygen-independent degradation depends on the release of granules, containing proteolytic enzymes such as defensins, lysozyme, other antimicrobial peptides are present in these granules, including lactoferrin, which sequesters iron to provide unfavourable growth conditions for bacteria. It is possible for other than dedicated phagocytes to engage in phagocytosis. Some white blood cells in human immune system perform phagocytosis by gulping in some pathogenic, following apoptosis, the dying cells need to be taken up into the surrounding tissues by macrophages in a process called efferocytosis. Defects in apoptotic cell clearance is usually associated with impaired phagocytosis of macrophages, in many protists, phagocytosis is used as a means of feeding, providing part or all of their nourishment. This is called phagotrophic nutrition, distinguished from osmotrophic nutrition which takes place by absorption, in some, such as amoeba, phagocytosis takes place by surrounding the target object with pseudopods, as in animal phagocytes. In humans, entamoeba histolytica can phagocytose red blood cells, Entamoeba histolytica is an anaerobic parasitic protozoan, part of the genus Entamoeba. Predominantly infecting humans and other primates, E. histolytica is estimated to infect about 50 million people worldwide
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Latin
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Latin is a classical language belonging to the Italic branch of the Indo-European languages. The Latin alphabet is derived from the Etruscan and Greek alphabets, Latin was originally spoken in Latium, in the Italian Peninsula. Through the power of the Roman Republic, it became the dominant language, Vulgar Latin developed into the Romance languages, such as Italian, Portuguese, Spanish, French, and Romanian. Latin, Italian and French have contributed many words to the English language, Latin and Ancient Greek roots are used in theology, biology, and medicine. By the late Roman Republic, Old Latin had been standardised into Classical Latin, Vulgar Latin was the colloquial form spoken during the same time and attested in inscriptions and the works of comic playwrights like Plautus and Terence. Late Latin is the language from the 3rd century. Later, Early Modern Latin and Modern Latin evolved, Latin was used as the language of international communication, scholarship, and science until well into the 18th century, when it began to be supplanted by vernaculars. Ecclesiastical Latin remains the language of the Holy See and the Roman Rite of the Catholic Church. Today, many students, scholars and members of the Catholic clergy speak Latin fluently and it is taught in primary, secondary and postsecondary educational institutions around the world. The language has been passed down through various forms, some inscriptions have been published in an internationally agreed, monumental, multivolume series, the Corpus Inscriptionum Latinarum. Authors and publishers vary, but the format is about the same, volumes detailing inscriptions with a critical apparatus stating the provenance, the reading and interpretation of these inscriptions is the subject matter of the field of epigraphy. The works of several hundred ancient authors who wrote in Latin have survived in whole or in part and they are in part the subject matter of the field of classics. The Cat in the Hat, and a book of fairy tales, additional resources include phrasebooks and resources for rendering everyday phrases and concepts into Latin, such as Meissners Latin Phrasebook. The Latin influence in English has been significant at all stages of its insular development. From the 16th to the 18th centuries, English writers cobbled together huge numbers of new words from Latin and Greek words, dubbed inkhorn terms, as if they had spilled from a pot of ink. Many of these words were used once by the author and then forgotten, many of the most common polysyllabic English words are of Latin origin through the medium of Old French. Romance words make respectively 59%, 20% and 14% of English, German and those figures can rise dramatically when only non-compound and non-derived words are included. Accordingly, Romance words make roughly 35% of the vocabulary of Dutch, Roman engineering had the same effect on scientific terminology as a whole
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Tonsil
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Tonsils are collections of lymphoid tissue facing into the aerodigestive tract. The set of tissue known as Waldeyers tonsillar ring includes the adenoid tonsil. When used unqualified, the term most commonly refers specifically to the palatine tonsils, the palatine tonsils and the nasopharyngeal tonsil are lymphoepithelial tissues located near the oropharynx and nasopharynx. Tonsils in humans include, from anterior, superior, posterior, and inferior, Tonsils tend to reach their largest size near puberty, however, they are largest relative to the diameter of the throat in young children. See also, The impact of tonsillectomy on the immune system These immunocompetent tissues are the systems first line of defense against ingested or inhaled foreign pathogens. Tonsils have on their surface specialized antigen capture cells called M cells that allow for the uptake of antigens produced by pathogens and these M cells then alert the underlying B cells and T cells in the tonsil that a pathogen is present and an immune response is stimulated. B cells are activated and proliferate in areas called germinal centres in the tonsil and these germinal centres are places where B memory cells are created and secretory antibody is produced. Recent studies have provided evidence that the tonsils produce T lymphocytes, also known as T-cells, in a similar to, but different from. Tonsils can become enlarged or inflamed and may require surgical removal and this may be indicated if they obstruct the airway or interfere with swallowing, or in patients with frequent recurrent tonsillitis. However, different mechanisms of pathogenesis for these two subtypes of tonsillar hypertrophy have been described, and may have different responses to identical therapeutic efforts, in older patients, asymmetric tonsils may be an indicator of virally infected tonsils, or tumors such as lymphoma or squamous cell carcinoma. Tonsillitis is a disorder in which the tonsils are inflamed, the most common way to treat it is with anti-inflammatory drugs such as ibuprofen, or if bacterial in origin, antibiotics, e. g. amoxicillin and azithromycin. Often severe and/or recurrent tonsillitis is treated by tonsillectomy, a tonsillolith is material that accumulates on the tonsil. They can range up to the size of a peppercorn and are white/cream in color, the main substance is mostly calcium, but they have a strong unpleasant odor because of hydrogen sulfide and methyl mercaptan and other chemicals. Tonsil enlargement can affect speech, making it hypernasal and giving it the sound of velopharyngeal incompetence, tonsil size may have a more significant impact on upper airway obstruction for obese children than for those of average weight. Other viewpoints treat them as large lymphatic organs contradistinguished from the smaller tissue loci of GALT and MALT, media related to Tonsils at Wikimedia Commons
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Lymphatic system
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The lymphatic system was first described in the seventeenth century independently by Olaus Rudbeck and Thomas Bartholin. Unlike the cardiovascular system, the system is not a closed system. The human circulatory system processes an average of 20 liters of blood per day through capillary filtration, roughly 17 litres of the filtered plasma are reabsorbed directly into the blood vessels, while the remaining three litres remain in the interstitial fluid. One of the functions of the lymph system is to provide an accessory return route to the blood for the surplus three litres. The other main function is that of defense in the immune system, lymph is very similar to blood plasma, it contains lymphocytes and other white blood cells. It also contains waste products and cellular debris together with bacteria, associated organs composed of lymphoid tissue are the sites of lymphocyte production. Lymphocytes are concentrated in the lymph nodes, the spleen and the thymus are also lymphoid organs of the immune system. The tonsils are lymphoid organs that are associated with the digestive system. Lymphoid tissues contain lymphocytes, and also other types of cells for support. Lymph is the fluid that is formed when interstitial fluid enters the lymphatic vessels of the lymphatic system. Eventually, the lymph vessels empty into the ducts, which drain into one of the two subclavian veins, near their junction with the internal jugular veins. The lymphatic system consists of lymphatic organs, a network of lymphatic vessels. The primary or central lymphoid organs generate lymphocytes from immature progenitor cells, the thymus and the bone marrow constitute the primary lymphoid organs involved in the production and early clonal selection of lymphocyte tissues. Bone marrow is responsible for both the creation of T cells and the production and maturation of B cells, from the bone marrow, B cells immediately join the circulatory system and travel to secondary lymphoid organs in search of pathogens. T cells, on the hand, travel from the bone marrow to the thymus. Mature T cells join B cells in search of pathogens, the other 95% of T cells begin a process of apoptosis, a form of programmed cell death. Secondary or peripheral lymphoid organs, which include lymph nodes and the spleen, maintain mature naive lymphocytes, the peripheral lymphoid organs are the sites of lymphocyte activation by antigens. Activation leads to clonal expansion and affinity maturation, mature lymphocytes recirculate between the blood and the peripheral lymphoid organs until they encounter their specific antigen
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Lymph node
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A lymph node or lymph gland, is an ovoid or kidney-shaped organ of the lymphatic system, and of the adaptive immune system, that is widely present throughout the body. They are linked by the vessels as a part of the circulatory system. Lymph nodes are major sites of B and T lymphocytes, Lymph nodes are important for the proper functioning of the immune system, acting as filters for foreign particles and cancer cells. Lymph nodes do not have a function, which is primarily dealt with by the liver. In the lymphatic system the lymph node is a secondary lymphoid organ, a lymph node is enclosed in a fibrous capsule and is made up of an outer cortex and an inner medulla. Lymph nodes also have clinical significance and they become inflamed or enlarged in various diseases which may range from trivial throat infections, to life-threatening cancers. The condition of the nodes is very important in cancer staging, which decides the treatment to be used. When swollen, inflamed or enlarged, lymph nodes can be hard, Lymph nodes are kidney or oval shaped and range in size from a few millimeters to about 1–2 cm long. Each lymph node is surrounded by a capsule, which extends inside the lymph node to form trabeculae. The substance of the node is divided into the outer cortex. The cortex is continuous around the medulla except where the medulla comes into contact with the hilum. Thin reticular fibers of reticular connective tissue, and elastin form a supporting meshwork called a reticulin inside the node, B cells, are mainly found in the outer where they are clustered together as follicular B cells in lymphoid follicles and the T cells are mainly in the paracortex. The number and composition of follicles can change especially when challenged by an antigen, elsewhere in the node, there are only occasional leucocytes. As part of the network there are follicular dendritic cells in the B cell follicle. The reticular network not only provides the support, but also the surface for adhesion of the dendritic cells. It allows exchange of material with blood through the high endothelial venules and provides the growth and regulatory factors necessary for activation and maturation of immune cells. All of these sinuses drain the filtered lymphatic fluid into the medullary sinuses and these vessels are smaller and dont allow the passage of the macrophages so that they remain contained to function within the lymph node. In the course of the lymph, lymphocytes may be activated as part of the immune response
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Surgery
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An act of performing surgery may be called a surgical procedure, operation, or simply surgery. In this context, the verb means to perform surgery. The adjective surgical means pertaining to surgery, e. g. surgical instruments or surgical nurse, the patient or subject on which the surgery is performed can be a person or an animal. A surgeon is a person who practices surgery and an assistant is a person who practices surgical assistance. A surgical team is made up of surgeon, surgeons assistant, anesthesia provider, circulating nurse, Surgery usually spans minutes to hours, but it is typically not an ongoing or periodic type of treatment. The term surgery can also refer to the place where surgery is performed, or simply the office of a physician, dentist, Surgery is a technology consisting of a physical intervention on tissues. As a general rule, a procedure is considered surgical when it involves cutting of a patients tissues or closure of a previously sustained wound, surgical procedures are commonly categorized by urgency, type of procedure, body system involved, degree of invasiveness, and special instrumentation. Based on timing, Elective surgery is done to correct a condition, and is carried out at the patients request, subject to the surgeons. A semi-elective surgery is one that must be done to avoid permanent disability or death, emergency surgery is surgery which must be done promptly to save life, limb, or functional capacity. Based on purpose, Exploratory surgery is performed to aid or confirm a diagnosis, therapeutic surgery treats a previously diagnosed condition. Cosmetic surgery is done to improve the appearance of an otherwise normal structure. By type of procedure, Amputation involves cutting off a part, usually a limb or digit. Resection is the removal of all or part of an organ or part of the body. Replantation involves reattaching a severed body part, reconstructive surgery involves reconstruction of an injured, mutilated, or deformed part of the body. Excision is the cutting out or removal of an organ, tissue, transplant surgery is the replacement of an organ or body part by insertion of another from different human into the patient. Removing an organ or body part from a human or animal for use in transplant is also a type of surgery. By body part, When surgery is performed on one system or structure. Examples include cardiac surgery, gastrointestinal surgery, and orthopedic surgery, by contrast, an open surgical procedure such as a laparotomy requires a large incision to access the area of interest
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Cell (biology)
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The cell is the basic structural, functional, and biological unit of all known living organisms. A cell is the smallest unit of life that can replicate independently, the study of cells is called cell biology. Cells consist of cytoplasm enclosed within a membrane, which contains many such as proteins. Organisms can be classified as unicellular or multicellular, while the number of cells in plants and animals varies from species to species, humans contain more than 10 trillion cells. Most plant and animal cells are only under a microscope. The cell was discovered by Robert Hooke in 1665, who named the unit for its resemblance to cells inhabited by Christian monks in a monastery. Cells emerged on Earth at least 3.5 billion years ago, Cells are of two types, eukaryotic, which contain a nucleus, and prokaryotic, which do not. Prokaryotes are single-celled organisms, while eukaryotes can be either single-celled or multicellular, prokaryotic cells were the first form of life on Earth, characterised by having vital biological processes including cell signaling and being self-sustaining. They are simpler and smaller than eukaryotic cells, and lack membrane-bound organelles such as the nucleus, prokaryotes include two of the domains of life, bacteria and archaea. The DNA of a prokaryotic cell consists of a chromosome that is in direct contact with the cytoplasm. The nuclear region in the cytoplasm is called the nucleoid, most prokaryotes are the smallest of all organisms ranging from 0.5 to 2.0 µm in diameter. Though most prokaryotes have both a cell membrane and a wall, there are exceptions such as Mycoplasma and Thermoplasma which only possess the cell membrane layer. The envelope gives rigidity to the cell and separates the interior of the cell from its environment, the cell wall consists of peptidoglycan in bacteria, and acts as an additional barrier against exterior forces. It also prevents the cell from expanding and bursting from osmotic pressure due to a hypotonic environment, some eukaryotic cells also have a cell wall. Inside the cell is the region that contains the genome, ribosomes. The genetic material is found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular, linear bacterial plasmids have been identified in several species of spirochete bacteria, including members of the genus Borrelia notably Borrelia burgdorferi, which causes Lyme disease. Though not forming a nucleus, the DNA is condensed in a nucleoid, plasmids encode additional genes, such as antibiotic resistance genes
. PMID 4536706.
