1.
Vanderbilt University
–
Vanderbilt University is a private research university founded in 1873 and located in Nashville, Tennessee. It was named in honor of shipping and rail magnate Cornelius Vanderbilt, Vanderbilt hoped that his gift and the greater work of the university would help to heal the sectional wounds inflicted by the Civil War. Today, Vanderbilt enrolls approximately 12,000 students from all 50 U. S. states and over 90 foreign countries in four undergraduate and six graduate, despite its urban surroundings, the campus itself is a national arboretum and features over 300 different species of trees and shrubs. Vanderbilt is ranked as one of the top universities for its teaching, research opportunities. It is ranked 15th on the list of best national universities generated by U. S. News & World Report, however, lack of funds and the ravaged state of the Reconstruction Era South delayed the opening of the college. Indeed, the McTyeires had met at St. Francis Street Methodist Church in Mobile, Cornelius Vanderbilt, who was the wealthiest man in the United States at the time, was considering philanthropy as he was at an advanced age. He had been planning to establish a university on Staten Island, New York, however, McTyeire convinced him to donate $500,000 to endow Central University in order to contribute to strengthening the ties which should exist between all sections of our common country. The endowment was increased to $1 million and would be only one of two philanthropic causes financially supported by Vanderbilt. Though he never expressed any desire that the university be named after himself, McTyeire, Vanderbilt died in 1877 without seeing the school named after him. One of the trustees, Hezekiah William Foote, was a Confederate veteran. The Treasurer of the Board of Trust from 1872 to 1875, Alexander Little Page Green, whose portrait hangs in Kirkland Hall, was a Methodist preacher and a former slave owner. His son-in-law, Robert A. Young, was a Methodist minister who served as the Financial Secretary on the Board of Trust from 1874 to 1882, retiring from the board in 1902. The first building, Main Building, later known as Kirkland Hall, was designed by William Crawford Smith, in the fall of 1875, about 200 students enrolled at Vanderbilt, and in October the university was dedicated. Bishop McTyeire was named Chairman of the Board of Trust for life by Vanderbilt as a stipulation of his endowment, McTyeire named Landon Garland, his mentor from Randolph-Macon College in Virginia and then-Chancellor of the University of Mississippi, as chancellor. Garland shaped the structure and hired the schools faculty, many of whom were renowned scholars in their respective fields. However, most of this faculty left after disputes with Bishop McTyeire, when the first fraternity chapter, Phi Delta Theta, was established on campus in 1876, it was shut down by the faculty, only to be reestablished as a secret society in 1877. Meanwhile, Old Gym, designed by Dutch-born architect Peter J. Williamson, was built in 1879–1880, by 1883, the Board of Trust passed a resolution allowing fraternities on campus, and more chapters were established in 1884. During the first 40 years, the Board of Trust, and therefore the university, was under the control of the General Conference of the Methodist Episcopal Church, conflicts escalated after James H. Kirkland was appointed chancellor in 1893
2.
Nobel Prize in Physiology or Medicine
–
The Nobel Prize in Physiology or Medicine, administered by the Nobel Foundation, is awarded once a year for outstanding discoveries in the fields of life sciences and medicine. It is one of five Nobel Prizes established in 1895 by Swedish chemist Alfred Nobel, Nobel was personally interested in experimental physiology and wanted to establish a prize for progress through scientific discoveries in laboratories. The Nobel Prize is presented to the recipient at a ceremony on 10 December, the anniversary of Nobels death, along with a diploma. The front side of the medal provides the profile of Alfred Nobel as depicted on the medals for Physics, Chemistry. As of 2015,106 Nobel Prizes in Physiology or Medicine have been awarded to 198 men and 12 women. The first Nobel Prize in Physiology or Medicine was awarded in 1901 to the German physiologist Emil von Behring, for his work on serum therapy and this includes one to António Egas Moniz in 1949 for the prefrontal leucotomy, bestowed despite protests from the medical establishment. Other controversies resulted from disagreements over who was included in the award, the 1952 prize to Selman Waksman was litigated in court, and half the patent rights awarded to his co-discoverer Albert Schatz who was not recognized by the prize. The 1962 prize awarded to James D, since the Nobel Prize rules forbid nominations of the deceased, longevity is an asset, one prize being awarded as long as 50 years after the discovery. Alfred Nobel was born on 21 October 1833 in Stockholm, Sweden into a family of engineers and he was a chemist, engineer and inventor who amassed a fortune during his lifetime, most of it from his 355 inventions of which dynamite is the most famous. He was interested in experimental physiology and set up his own labs in France, in 1888, Nobel was surprised to read his own obituary, titled The merchant of death is dead, in a French newspaper. Though Nobel wrote several wills during his lifetime, the last was written a little over a year before he died at the age of 63, because his will was contested, it was not approved by the Storting until 26 April 1897. After Nobels death, the Nobel Foundation was set up to manage the assets of the bequest, in 1900, the Nobel Foundations newly created statutes were promulgated by Swedish King Oscar II. According to Nobels will, the Karolinska Institutet in Sweden, a medical school, today, the prize is commonly referred to as the Nobel Prize in Medicine. It was important to Nobel that the prize be awarded for a discovery, per the provisions of the will, only select persons are eligible to nominate individuals for the award. Past Nobel laureates may also nominate, until 1977, all professors of Karolinska Institutet together decided on the Nobel Prize in Physiology or Medicine. Therefore, the Nobel Assembly was constituted, consisting of 50 professors at Karolinska Institutet. It elects the Nobel Committee with 5 members who evaluate the nominees, the Secretary who is in charge of the organization, in 1968, a provision was added that no more than three persons may share a Nobel prize. True to its mandate, the Committee has selected researchers working in the sciences over those who have made applied contributions
3.
Sugar
–
Sugar is the generic name for sweet, soluble carbohydrates, many of which are used in food. There are various types of derived from different sources. Simple sugars are called monosaccharides and include glucose, fructose, the table sugar or granulated sugar most customarily used as food is sucrose, a disaccharide of glucose and fructose. Sugar is used in prepared foods and it is added to some foods, in the body, sucrose is hydrolysed into the simple sugars fructose and glucose. Other disaccharides include maltose from malted grain, and lactose from milk, longer chains of sugars are called oligosaccharides or polysaccharides. Some other chemical substances, such as glycerol may also have a sweet taste, low-calorie food substitutes for sugar, described as artificial sweeteners, include aspartame and sucralose, a chlorinated derivative of sucrose. Sugars are found in the tissues of most plants and are present in sufficient concentrations for efficient commercial extraction in sugarcane, the world production of sugar in 2011 was about 168 million tonnes. The average person consumes about 24 kilograms of sugar each year, equivalent to over 260 food calories per person, since the latter part of the twentieth century, it has been questioned whether a diet high in sugars, especially refined sugars, is good for human health. Sugar has been linked to obesity, and suspected of, or fully implicated as a cause in the occurrence of diabetes, cardiovascular disease, dementia, macular degeneration, the etymology reflects the spread of the commodity. The English word sugar ultimately originates from the Sanskrit शर्करा, via Arabic سكر as granular or candied sugar, the contemporary Italian word is zucchero, whereas the Spanish and Portuguese words, azúcar and açúcar, respectively, have kept a trace of the Arabic definite article. The Old French word is zuchre and the contemporary French, sucre, the earliest Greek word attested is σάκχαρις. The English word jaggery, a brown sugar made from date palm sap or sugarcane juice, has a similar etymological origin – Portuguese jagara from the Sanskrit शर्करा. Sugar has been produced in the Indian subcontinent since ancient times and it was not plentiful or cheap in early times and honey was more often used for sweetening in most parts of the world. Originally, people chewed raw sugarcane to extract its sweetness, sugarcane was a native of tropical South Asia and Southeast Asia. Different species seem to have originated from different locations with Saccharum barberi originating in India and S. edule, one of the earliest historical references to sugarcane is in Chinese manuscripts dating back to 8th century BC that state that the use of sugarcane originated in India. Sugar was found in Europe by the 1st century AD, but only as an imported medicine and it is a kind of honey found in cane, white as gum, and it crunches between the teeth. It comes in lumps the size of a hazelnut, sugar is used only for medical purposes. Sugar remained relatively unimportant until the Indians discovered methods of turning sugarcane juice into granulated crystals that were easier to store, crystallized sugar was discovered by the time of the Imperial Guptas, around the 5th century AD
4.
Metabolism
–
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
5.
Jmol
–
Jmol is computer software for molecular modelling chemical structures in 3-dimensions. Jmol returns a 3D representation of a molecule that may be used as a teaching tool and it is written in the programming language Java, so it can run on the operating systems Windows, macOS, Linux, and Unix, if Java is installed. It is free and open-source software released under a GNU Lesser General Public License version 2.0, a standalone application and a software development kit exist that can be integrated into other Java applications, such as Bioclipse and Taverna. A popular feature is an applet that can be integrated into web pages to display molecules in a variety of ways, for example, molecules can be displayed as ball-and-stick models, space-filling models, ribbon diagrams, etc. Jmol supports a range of chemical file formats, including Protein Data Bank, Crystallographic Information File, MDL Molfile. There is also a JavaScript-only version, JSmol, that can be used on computers with no Java, the Jmol applet, among other abilities, offers an alternative to the Chime plug-in, which is no longer under active development. While Jmol has many features that Chime lacks, it does not claim to reproduce all Chime functions, most notably, Chime requires plug-in installation and Internet Explorer 6.0 or Firefox 2.0 on Microsoft Windows, or Netscape Communicator 4.8 on Mac OS9. Jmol requires Java installation and operates on a variety of platforms. For example, Jmol is fully functional in Mozilla Firefox, Internet Explorer, Opera, Google Chrome, fast and Scriptable Molecular Graphics in Web Browsers without Java3D
6.
Adenylyl cyclase
–
Adenylyl cyclase is an enzyme with key regulatory roles in essentially all cells. The best known class of adenylyl cyclases is class III or AC-III, AC-III occurs widely in eukaryotes and has important roles in many human tissues. All classes of adenylyl cyclases catalyse the conversion of adenosine triphosphate to 3, 5-cyclic AMP, magnesium ions are generally required and appears to be closely involved in the enzymatic mechanism. The cAMP produced by AC then serves as a signal via specific cAMP-binding proteins, either transcription factors, enzymes. The first class of adenylyl cyclases occur in bacteria including E. coli. This was the first class of AC to be characterized and it was observed that E. coli deprived of glucose produce cAMP that serves as an internal signal to activate expression of genes for importing and metabolizing other sugars. CAMP exerts this effect by binding the transcription factor CRP, also known as CAP, Class I ACs are large cytosolic enzymes with a large regulatory domain that indirectly senses glucose levels. As of 2012, no crystal structure is available for class I AC and these adenylyl cyclases are toxins secreted by pathogenic bacteria such as Bacillus anthracis and Bordetella pertussis during infection. These bacteria also secrete proteins that enable the AC-II to enter host cells, the genes for Class II ACs are known as cyaA. Several crystal structures are known for AC-II enzymes and these adenylyl cyclases are the most familiar based on extensive study due to their important roles in human health. They are also found in bacteria, notably Mycobacterium tuberculosis where they appear to have a key role in pathogenesis. Most AC-IIIs are integral membrane proteins involved in transducing extracellular signals into intracellular responses, the effect of adrenaline is via a G protein signaling cascade, which transmits chemical signals from outside the cell across the membrane to the inside of the cell. CAMP is known as a second messenger, cyclic AMP is an important molecule in eukaryotic signal transduction, a so-called second messenger. Adenylyl cyclases are often activated or inhibited by G proteins, which are coupled to membrane receptors, photoactivatable adenylyl cyclase was discovered in E. gracilis and can be expressed in other organisms through genetic manipulation. Shining blue light on a cell containing PAC activates it and abruptly increases the rate of conversion of ATP to cAMP, for example, PAC expression in certain neurons has been shown to alter the grooming behavior in fruit flies exposed to blue light. Channelrhodopsin-2 is also used in a similar fashion, most class III adenylyl cyclases are transmembrane proteins with 12 transmembrane segments. The protein is organized with 6 transmembrane segments, then the C1 cytoplasmic domain, then another 6 membrane segments, the important parts for function are the N-terminus and the C1 and C2 regions. The C1a and C2a subdomains are homologous and form a dimer that forms the active site
7.
Catalysis
–
Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst. In most cases, reactions occur faster with a catalyst because they require less activation energy, furthermore, since they are not consumed in the catalyzed reaction, catalysts can continue to act repeatedly. Often only tiny amounts are required in principle, in the presence of a catalyst, less free energy is required to reach the transition state, but the total free energy from reactants to products does not change. A catalyst may participate in multiple chemical transformations, the effect of a catalyst may vary due to the presence of other substances known as inhibitors or poisons or promoters. Catalyzed reactions have an activation energy than the corresponding uncatalyzed reaction, resulting in a higher reaction rate at the same temperature. However, the mechanics of catalysis is complex. Usually, the catalyst participates in this slowest step, and rates are limited by amount of catalyst, in heterogeneous catalysis, the diffusion of reagents to the surface and diffusion of products from the surface can be rate determining. A nanomaterial-based catalyst is an example of a heterogeneous catalyst, analogous events associated with substrate binding and product dissociation apply to homogeneous catalysts. Although catalysts are not consumed by the reaction itself, they may be inhibited, deactivated, in heterogeneous catalysis, typical secondary processes include coking where the catalyst becomes covered by polymeric side products. Additionally, heterogeneous catalysts can dissolve into the solution in a system or sublimate in a solid–gas system. The production of most industrially important chemicals involves catalysis, similarly, most biochemically significant processes are catalysed. Research into catalysis is a field in applied science and involves many areas of chemistry, notably organometallic chemistry. Catalysis is relevant to aspects of environmental science, e. g. the catalytic converter in automobiles. Many transition metals and transition metal complexes are used in catalysis as well, Catalysts called enzymes are important in biology. A catalyst works by providing a reaction pathway to the reaction product. The rate of the reaction is increased as this route has a lower activation energy than the reaction route not mediated by the catalyst. The disproportionation of hydrogen peroxide creates water and oxygen, as shown below,2 H2O2 →2 H2O + O2 This reaction is preferable in the sense that the reaction products are more stable than the starting material, though the uncatalysed reaction is slow. In fact, the decomposition of hydrogen peroxide is so slow that hydrogen peroxide solutions are commercially available and this reaction is strongly affected by catalysts such as manganese dioxide, or the enzyme peroxidase in organisms
8.
Dictyostelid
–
The dictyostelids are a group of cellular slime molds, or social amoebae. When food is readily available dictyostelids behave as individual amoebae, which feed, however, when the food supply is exhausted, they aggregate to form a multicellular assembly, called a pseudoplasmodium, grex, or slug. The grex has an anterior and posterior, responds to light and temperature gradients. Under the correct circumstances the grez matures forming a sorocarp with a supporting one or more sori. These spores are inactive cells protected by resistant cell walls, in Acytostelium, the sorocarp is supported by a stalk composed of cellulose, but in other dictyostelids the stalk is composed of cells, sometimes taking up the majority of the original amoebae. With a few exceptions, these cells die during stalk formation, aggregation of amoebae generally takes place in converging streams. The amoebae move using filose pseudopods, and are attracted to chemicals produced by other amoebae, in Dictyostelium, aggregation is signalled by cAMP, but others use different chemicals. In the species Dictyostelium purpureum, the grouping is by kinship, Dictyostelium has been used as a model organism in molecular biology and genetics, and is studied as an example of cell communication, differentiation, and programmed cell death. It is also an example of the evolution of cooperation. A large body of data concerning D. discoideum is available on-line at DictyBase. The mechanism behind the aggregation of the amoebae relies on Cyclic adenosine monophosphate as a signal molecule, one cell, the founder of the colony, begins to secrete cAMP in response to stress. Others detect this signal, and respond in two ways, The amoeba moves towards the signal, the amoeba secretes more cAMP to boost the signal. The effect of this is to relay the signal throughout the population of amoebae. A different g-protein stimulates Phospholipase C IP3 induces calcium ion release Calcium ions act on the cytoskeleton to induce the extension of pseudopodia, because the internal cAMP concentration inactivates the receptor for external cAMP, an individual cell shows oscillatory behaviour. This behaviour produces beautiful spirals seen in converging colonies and is reminiscent of the Belousov-Zhabotinsky reaction, the entire genome of Dictyostelium discoideum was published in Nature in 2005 by geneticist Ludwig Eichinger and coworkers. The haploid genome contains approximately 12,500 genes on 6 chromosomes, for comparison, the diploid human genome has 20, 000-25,000 genes on 23 chromosome pairs. There is a level of the nucleotides adenosine and thymidine leading to a codon usage that favors more adenosines and thymidines in the third position. Tandem repeats of trinucleotides are abundant in Dictyostelium, which in humans cause Trinucleotide repeat disorders, sexual development can occur when amoeboid cells are starved for their bacterial food supply and dark humid conditions are present
9.
Signal transduction
–
Proteins responsible for detecting stimuli are generally termed receptors, although in some cases the term sensor is used. The changes elicited by ligand binding in a receptor give rise to a cascade of events along a signalling pathway. When signalling pathways interact with one another they form networks, which allow cellular responses to be coordinated and these molecular events are the basic mechanisms controlling cell growth, proliferation, metabolism and many other processes. In multicellular organisms, signal transduction pathways have evolved to regulate cell communication in a variety of ways. Each component of a pathway is classified according to the role it plays with respect to the initial stimulus. Ligands are termed first messengers, while receptors are the signal transducers, such effectors are often linked to second messengers, which can activate secondary effectors, and so on. Depending on the efficiency of the nodes, a signal can be amplified, as with other signals, the transduction of biological signals is characterised by delay, noise and interference, which can range from negligible to pathological. With the advent of computational biology, the analysis of signalling pathways and networks has become a tool to understand cellular functions. The basis for signal transduction is the transformation of a certain stimulus into a biochemical signal, traditionally, signals that reach the central nervous system are classified as senses. These are transmitted from neuron to neuron in a process called synaptic transmission, many other intercellular signal relay mechanisms exist in multicellular organisms, such as those that govern embryonic development. The majority of signal transduction pathways involve the binding of signalling molecules, known as ligands, the combination of a signaling molecule with a receptor causes a change in the conformation of the receptor, known as receptor activation. Most ligands are soluble molecules from the medium which bind to cell surface receptors. These include growth factors, cytokines and neurotransmitters, components of the extracellular matrix such as fibronectin and hyaluronan can also bind to such receptors. In addition, some such as steroid hormones are lipid-soluble. In the case of hormone receptors, their stimulation leads to binding to the promoter region of steroid-responsive genes. Not all classifications of signalling molecules take into account the nature of each class member. For example, odorants belong to a range of molecular classes, as do neurotransmitters. Moreover, some molecules may fit more than one class, e. g. epinephrine is a neurotransmitter when secreted by the central nervous system
10.
European Chemicals Agency
–
ECHA is the driving force among regulatory authorities in implementing the EUs chemicals legislation. ECHA helps companies to comply with the legislation, advances the safe use of chemicals, provides information on chemicals and it is located in Helsinki, Finland. The Agency, headed by Executive Director Geert Dancet, started working on 1 June 2007, the REACH Regulation requires companies to provide information on the hazards, risks and safe use of chemical substances that they manufacture or import. Companies register this information with ECHA and it is freely available on their website. So far, thousands of the most hazardous and the most commonly used substances have been registered, the information is technical but gives detail on the impact of each chemical on people and the environment. This also gives European consumers the right to ask whether the goods they buy contain dangerous substances. The Classification, Labelling and Packaging Regulation introduces a globally harmonised system for classifying and labelling chemicals into the EU. This worldwide system makes it easier for workers and consumers to know the effects of chemicals, companies need to notify ECHA of the classification and labelling of their chemicals. So far, ECHA has received over 5 million notifications for more than 100000 substances, the information is freely available on their website. Consumers can check chemicals in the products they use, Biocidal products include, for example, insect repellents and disinfectants used in hospitals. The Biocidal Products Regulation ensures that there is information about these products so that consumers can use them safely. ECHA is responsible for implementing the regulation, the law on Prior Informed Consent sets guidelines for the export and import of hazardous chemicals. Through this mechanism, countries due to hazardous chemicals are informed in advance and have the possibility of rejecting their import. Substances that may have effects on human health and the environment are identified as Substances of Very High Concern 1. These are mainly substances which cause cancer, mutation or are toxic to reproduction as well as substances which persist in the body or the environment, other substances considered as SVHCs include, for example, endocrine disrupting chemicals. Companies manufacturing or importing articles containing these substances in a concentration above 0 and they are required to inform users about the presence of the substance and therefore how to use it safely. Consumers have the right to ask the retailer whether these substances are present in the products they buy, once a substance has been officially identified in the EU as being of very high concern, it will be added to a list. This list is available on ECHA’s website and shows consumers and industry which chemicals are identified as SVHCs, Substances placed on the Candidate List can then move to another list
11.
Lipid
–
In biology, lipids comprise a group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins, monoglycerides, diglycerides, triglycerides, phospholipids, and others. The main biological functions of lipids include storing energy, signaling, lipids have applications in the cosmetic and food industries as well as in nanotechnology. Biological lipids originate entirely or in part from two types of biochemical subunits or building-blocks, ketoacyl and isoprene groups. Although the term lipid is sometimes used as a synonym for fats, fats are a subgroup of lipids called triglycerides, lipids also encompass molecules such as fatty acids and their derivatives, as well as other sterol-containing metabolites such as cholesterol. Although humans and other mammals use various biosynthetic pathways both to break down and to synthesize lipids, some essential lipids cannot be made this way, the word lipid stems etymologically from the Greek lipos. The fatty acid structure is one of the most fundamental categories of biological lipids, the carbon chain, typically between four and 24 carbons long, may be saturated or unsaturated, and may be attached to functional groups containing oxygen, halogens, nitrogen, and sulfur. If a fatty acid contains a double bond, there is the possibility of either a cis or trans geometric isomerism, cis-double bonds cause the fatty acid chain to bend, an effect that is compounded with more double bonds in the chain. This in turn plays an important role in the structure and function of cell membranes, most naturally occurring fatty acids are of the cis configuration, although the trans form does exist in some natural and partially hydrogenated fats and oils. Examples of biologically important fatty acids include the eicosanoids, derived primarily from arachidonic acid and eicosapentaenoic acid, that include prostaglandins, leukotrienes, docosahexaenoic acid is also important in biological systems, particularly with respect to sight. Other major lipid classes in the fatty acid category are the fatty esters, fatty esters include important biochemical intermediates such as wax esters, fatty acid thioester coenzyme A derivatives, fatty acid thioester ACP derivatives and fatty acid carnitines. The fatty amides include N-acyl ethanolamines, such as the cannabinoid neurotransmitter anandamide, glycerolipids are composed of mono-, di-, and tri-substituted glycerols, the best-known being the fatty acid triesters of glycerol, called triglycerides. The word triacylglycerol is sometimes used synonymously with triglyceride, in these compounds, the three hydroxyl groups of glycerol are each esterified, typically by different fatty acids. Because they function as a store, these lipids comprise the bulk of storage fat in animal tissues. The hydrolysis of the bonds of triglycerides and the release of glycerol. Additional subclasses of glycerolipids are represented by glycosylglycerols, which are characterized by the presence of one or more sugar residues attached to glycerol via a glycosidic linkage, examples of structures in this category are the digalactosyldiacylglycerols found in plant membranes and seminolipid from mammalian sperm cells. Glycerophospholipids, usually referred to as phospholipids, are ubiquitous in nature and are key components of the bilayer of cells, as well as being involved in metabolism. Neural tissue contains high amounts of glycerophospholipids, and alterations in their composition has been implicated in various neurological disorders. Examples of glycerophospholipids found in biological membranes are phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine, the major sphingoid base of mammals is commonly referred to as sphingosine
12.
Chemotaxis
–
Chemotaxis is the movement of an organism in response to a chemical stimulus. Somatic cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemicals in their environment and this is important for bacteria to find food by swimming toward the highest concentration of food molecules, or to flee from poisons. In multicellular organisms, chemotaxis is critical to development and subsequent phases of development as well as in normal function. In addition, it has recognized that mechanisms that allow chemotaxis in animals can be subverted during cancer metastasis. Positive chemotaxis occurs if the movement is toward a higher concentration of the chemical in question, chemically prompted kinesis can be called chemokinesis. Metchnikoff also contributed to the study of the field, with investigations of the process as a step of phagocytosis. The significance of chemotaxis in biology and clinical pathology was widely accepted in the 1930s, the availability of this technology led to the discovery of C5a, a major chemotactic factor involved in acute inflammation. The pioneering works of J. Adler represented a significant turning point in understanding the process of intracellular signal transduction of bacteria. Research on cell migration applies complementary techniques, classical and modern, the field of studies in chemotaxis contributes both basic research and applied science. Also incorporate data on migration and chemotaxis. Of the various ares of research into diverse, known taxis phenomena—e. g, thermotaxis, geotaxis, phototaxis), etc. —chemotaxis research contributes a significant proportion overall, underscoring the fundamental importance of chemotaxis research in biology and medicine. Chemoattractants and chemorepellents are inorganic or organic substances possessing chemotaxis-inducer effect in motile cells, effects of chemoattractants are elicited via described or hypothetic chemotaxis receptors, the chemoattractant moiety of a ligand is target cell specific and concentration dependent. Most frequently investigated chemoattractants are formyl peptides and chemokines, responses to chemorepellents result in axial swimming and they are considered a basic motile phenomena in bacteria. The most frequently investigated chemorepellents are inorganic salts, amino acids, some bacteria, such as E. coli, have several flagella per cell. The directions of rotation are given for an observer outside the cell looking down the flagella toward the cell, the overall movement of a bacterium is the result of alternating tumble and swim phases. If one watches a bacterium swimming in an environment, its movement will look like a random walk with relatively straight swims interrupted by random tumbles that reorient the bacterium. In the presence of a chemical gradient bacteria will chemotax, or direct their overall motion based on the gradient, even under very high concentrations, it can still distinguish very small differences in concentration, and fleeing from a repellent works with the same efficiency. This biased random walk is a result of choosing between two methods of random movement, namely tumbling and straight swimming
verify (what is 
?)
