Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes within and relating to living organisms. Biochemical processes give rise to the complexity of life. A sub-discipline of both biology and chemistry, biochemistry can be divided in three fields. Over the last decades of the 20th century, biochemistry has through these three disciplines become successful at explaining living processes. All areas of the life sciences are being uncovered and developed by biochemical methodology and research. Biochemistry focuses on understanding how biological molecules give rise to the processes that occur within living cells and between cells, which in turn relates to the study and understanding of tissues and organism structure and function. Biochemistry is related to molecular biology, the study of the molecular mechanisms by which genetic information encoded in DNA is able to result in the processes of life. Much of biochemistry deals with the structures and interactions of biological macromolecules, such as proteins, nucleic acids and lipids, which provide the structure of cells and perform many of the functions associated with life.
The chemistry of the cell depends on the reactions of smaller molecules and ions. These can be inorganic, for example water and metal ions, or organic, for example the amino acids, which are used to synthesize proteins; the mechanisms by which cells harness energy from their environment via chemical reactions are known as metabolism. The findings of biochemistry are applied in medicine and agriculture. In medicine, biochemists investigate the cures of diseases. In nutrition, they study how to maintain health wellness and study the effects of nutritional deficiencies. In agriculture, biochemists investigate soil and fertilizers, try to discover ways to improve crop cultivation, crop storage and pest control. At its broadest definition, biochemistry can be seen as a study of the components and composition of living things and how they come together to become life, in this sense the history of biochemistry may therefore go back as far as the ancient Greeks. However, biochemistry as a specific scientific discipline has its beginning sometime in the 19th century, or a little earlier, depending on which aspect of biochemistry is being focused on.
Some argued that the beginning of biochemistry may have been the discovery of the first enzyme, diastase, in 1833 by Anselme Payen, while others considered Eduard Buchner's first demonstration of a complex biochemical process alcoholic fermentation in cell-free extracts in 1897 to be the birth of biochemistry. Some might point as its beginning to the influential 1842 work by Justus von Liebig, Animal chemistry, or, Organic chemistry in its applications to physiology and pathology, which presented a chemical theory of metabolism, or earlier to the 18th century studies on fermentation and respiration by Antoine Lavoisier. Many other pioneers in the field who helped to uncover the layers of complexity of biochemistry have been proclaimed founders of modern biochemistry, for example Emil Fischer for his work on the chemistry of proteins, F. Gowland Hopkins on enzymes and the dynamic nature of biochemistry; the term "biochemistry" itself is derived from a combination of chemistry. In 1877, Felix Hoppe-Seyler used the term as a synonym for physiological chemistry in the foreword to the first issue of Zeitschrift für Physiologische Chemie where he argued for the setting up of institutes dedicated to this field of study.
The German chemist Carl Neuberg however is cited to have coined the word in 1903, while some credited it to Franz Hofmeister. It was once believed that life and its materials had some essential property or substance distinct from any found in non-living matter, it was thought that only living beings could produce the molecules of life. In 1828, Friedrich Wöhler published a paper on the synthesis of urea, proving that organic compounds can be created artificially. Since biochemistry has advanced since the mid-20th century, with the development of new techniques such as chromatography, X-ray diffraction, dual polarisation interferometry, NMR spectroscopy, radioisotopic labeling, electron microscopy, molecular dynamics simulations; 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, led to an understanding of biochemistry on a molecular level. Philip Randle is well known for his discovery in diabetes research is the glucose-fatty acid cycle in 1963.
He confirmed. High fat oxidation was responsible for the insulin resistance. Another significant historic event in biochemistry is the discovery of the gene, its role in the transfer of information in the cell; this part of biochemistry is called molecular biology. In the 1950s, James D. Watson, Francis Crick, Rosalind Franklin, Maurice Wilkins were instrumental in solving DNA structure and suggesting its relationship with genetic transfer of information. 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, which led to the growth of forensic science. More Andrew Z. Fire and Craig C. 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
Wickenburg, Arizona
Wickenburg is a town located in Maricopa County, United States, with a portion in neighboring Yavapai County. According to the 2010 census, the population of the town is 6,363; the Wickenburg area with much of the Southwest became part of the United States by the 1848 treaty that ended the Mexican–American War. The first extensive survey was conducted by Gila Rangers who were pursuing hostile Indians who had raided the Butterfield Overland Mail route and attacked miners at Gila City. In 1862, a gold strike on the Colorado River near present-day Yuma brought American prospectors, who searched for minerals throughout central Arizona. Many of the geographic landmarks now bear the names of these pioneers, including the Weaver Mountains, named after mountain man Pauline Weaver, Peeples Valley, named after a settler. A German named, his efforts were rewarded with the discovery of the Vulture Mine, from which more than $30 million worth of gold has been dug. Ranchers and farmers soon built homes along the fertile plain of the Hassayampa River.
Together with the miners, they founded the town of Wickenburg in 1863. Wickenburg was the home of Jack Swilling, who prospected in the Salt River Valley in 1867. Swilling helped ground the city of Phoenix, Arizona. Wickenburg was supplied from the Colorado River, by steamboat over the La Paz - Wikenburg Road by wagons and pack mules. Wickenburg in turn became a supply point for the mines and army posts in the interior of Arizona Territory; as the town grew, conflicts developed with the Yavapai Native American tribe, who rejected a treaty signed by their chiefs breaking the treaty. When the American Civil War began in 1861, the Federal troops were all withdrawn and the settlements were left unprotected; the Yavapai promptly began a series of attacks on the white intruders. A company of Confederate cavalry brought temporary relief, but it fell back before the advance of Union troops from California. By 1869, an estimated 1000 Yavapai and 400 settlers had been killed, with many on both sides fleeing to safer areas.
With the end of the war, the Union troops and local volunteers forced the Yavapai onto a reservation, where they remain to this day. However, Yavapai recalcitrants remained for years, raids on stage-coaches, isolated farm houses, periodic raids on villages kept the area in a constant state of tension. Following several murders of Yavapai chiefs allied with America by insurgent Yavapai warriors, hostile warrior tribal leaders mobilized the entire Yavapai warrior band into a massive assault on the primary American settlement of Wickenburg and massacred or drove out much of the American populace. In 1872, in response to the assassination of friendly Yavapai chiefs, the take-over of the entire Yavapai nation and its reservation by hostile elements, with most of the American area under continual penetrating raids by Yavapai warrior bands, General George Crook began an all-out campaign against the Yavapai, with the aim of forcing the insurgent Yavapai warrior bands into a decisive battle and the removal of Yavapai settlers from American territory.
After several months of forced marches and pitched skirmishes by combined Arizona territorial militia and US Army Cavalry, Crook forced the Yavapai bands into a single decisive battle. In December 1872, the Battle of Salt River Canyon in the Superstition Mountains decisively routed the Yavapai, within a year most Yavapai resistance was crushed. Having broken their treaty with America several times, with most of the friendly and allied chiefs killed by insurgent Yavapais, who killed Americans, Crook was authorized to enter into new negotiations with the aim of reducing the size of the Yavapai reservation and removing it to an area more cordoned off from American communities and their communication lines; the surviving Yavapai warrior leaders grudgingly accepted the treaty which left the nation in far worse conditions than previously. They were compelled to surrender their firearms, move to the Fort Verde Reservation, accept a permanent Army garrison on their territory, accept direct administration by American Bureau of Indian Affairs agents and commissioners, have trade emplaced in the hands of American government agents, be regulated by an Indian Police force picked and trained by the US Army and Arizona Territorial officers.
After only two years on the Rio Verde Reservation, local officials grew concerned about the Yavapais' continued hostility and self-sufficiency, so they persuaded the federal government to close their reservation and move all the Yavapai to the San Carlos Apache Indian Reservation. The infant town of Wickenburg went through many trials and tribulations in its first decades, surviving the Indian Wars including repeating Indian raids, mine closures, a disastrous flood in 1890 when the Walnut Creek Dam burst, killing nearly 70 residents. In spite of such challenging circumstances, the town continued to grow, its prosperity was ensured with the coming of the railroad in 1895. In those years, the town had once been viewed as a possible candidate for territorial capital; the historic train depot today houses the Visitor's Center. As of 2007, only freight trains pass through Wickenburg. Along the town's main historic district, early businesses built many structures that still form Wickenburg's downtown area.
Tourism led to the development of guest ranches, with as many as 14 operating in the 1950s and 60s, when Wickenburg billed itself as the "Dude Ranch Capital of the World", with development spurred by the construction of. As of 2007, some
Columbia University
Columbia University is a private Ivy League research university in Upper Manhattan, New York City. Established in 1754, Columbia is the oldest institution of higher education in New York and the fifth-oldest institution of higher learning in the United States, it is one of nine colonial colleges founded prior to the Declaration of Independence, seven of which belong to the Ivy League. It has been ranked by numerous major education publications as among the top ten universities in the world. Columbia was established as King's College by royal charter of George II of Great Britain in reaction to the founding of Princeton University in New Jersey, it was renamed Columbia College in 1784 following the Revolutionary War and in 1787 was placed under a private board of trustees headed by former students Alexander Hamilton and John Jay. In 1896, the campus was moved from Madison Avenue to its current location in Morningside Heights and renamed Columbia University. Columbia scientists and scholars have played an important role in the development of notable scientific fields and breakthroughs including: brain-computer interface.
The Columbia University Physics Department has been affiliated with 33 Nobel Prize winners as alumni, faculty or research staff, the third most of any American institution behind MIT and Harvard. In addition, 22 Nobel Prize winners in Physiology and Medicine have been affiliated with Columbia, the third most of any American institution; the university's research efforts include the Lamont-Doherty Earth Observatory, Goddard Institute for Space Studies and accelerator laboratories with major technology firms such as IBM. Columbia is one of the fourteen founding members of the Association of American Universities and was the first school in the United States to grant the M. D. degree. The university administers the Pulitzer Prize annually. Columbia is organized into twenty schools, including three undergraduate schools and numerous graduate schools, it maintains research centers outside of the United States known as Columbia Global Centers. In 2018, Columbia's undergraduate acceptance rate was 5.1%, making it one of the most selective colleges in the United States, the second most selective in the Ivy League after Harvard.
Columbia is ranked as the 3rd best university in the United States by U. S. News & World Report behind Princeton and Harvard. In athletics, the Lions field varsity teams in 29 sports as a member of the NCAA Division I Ivy League conference; the university's endowment stood at $10.9 billion in 2018, among the largest of any academic institution. As of 2018, Columbia's alumni and affiliates include: five Founding Fathers of the United States — among them an author of the United States Constitution and co-author of the Declaration of Independence. S. presidents. Discussions regarding the founding of a college in the Province of New York began as early as 1704, at which time Colonel Lewis Morris wrote to the Society for the Propagation of the Gospel in Foreign Parts, the missionary arm of the Church of England, persuading the society that New York City was an ideal community in which to establish a college. However, it was not until the founding of the College of New Jersey across the Hudson River in New Jersey that the City of New York considered founding a college.
In 1746, an act was passed by the general assembly of New York to raise funds for the foundation of a new college. In 1751, the assembly appointed a commission of ten New York residents, seven of whom were members of the Church of England, to direct the funds accrued by the state lottery towards the foundation of a college. Classes were held in July 1754 and were presided over by the college's first president, Dr. Samuel Johnson. Dr. Johnson was the only instructor of the college's first class, which consisted of a mere eight students. Instruction was held in a new schoolhouse adjoining Trinity Church, located on what is now lower Broadway in Manhattan; the college was founded on October 31, 1754, as King's College by royal charter of King George II, making it the oldest institution of higher learning in the state of New York and the fifth oldest in the United States. In 1763, Dr. Johnson was succeeded in the presidency by Myles Cooper, a graduate of The Queen's College, an ardent Tory. In the charged political climate of the American Revolution, his chief opponent in discussions at the college was an undergraduate of the class of 1777, Alexander Hamilton.
The American Revolutionary War broke out in 1776, was catastrophic for the operation of King's College, which suspended instruction for eight years beginning in 1776 with the arrival of the Continental Army. The suspension continued through the military occupation of New York City by British troops until their departure in 1783; the college's library was looted and its sole building requisitioned for use as a military hospital first by American and British forces. Loyalists were forced to abandon their King's College in New York, seized by the rebels and renamed Columbia College; the Loyalists, led by Bishop Charles Inglis fled to Windsor, Nova Scotia, where the
Svante Arrhenius
Svante August Arrhenius was a Swedish scientist. A physicist, but referred to as a chemist, Arrhenius was one of the founders of the science of physical chemistry, he received the Nobel Prize for Chemistry in 1903, becoming the first Swedish Nobel laureate, in 1905 became director of the Nobel Institute where he remained until his death. He was the first to use basic principles of physical chemistry to calculate estimates of the extent to which increases in atmospheric carbon dioxide increase the Earth's surface temperature, leading David Keeling to conclude, demonstrate in the 1960s, that human-caused carbon dioxide emissions are large enough to cause global warming, his lasting contributions to science are exemplified and memorialized by the Arrhenius equation, Arrhenius acid, lunar crater Arrhenius, Martian crater Arrhenius, the mountain of Arrheniusfjellet, the Arrhenius Labs at Stockholm University. Arrhenius was born on 19 February 1859 at Vik, near Uppsala, the son of Svante Gustav and Carolina Thunberg Arrhenius.
His father had been a land surveyor for Uppsala University. At the age of three, Arrhenius taught himself to read without the encouragement of his parents, by watching his father's addition of numbers in his account books, became an arithmetical prodigy. In life, Arrhenius enjoyed using masses of data to discover mathematical relationships and laws. At age eight, he entered the local cathedral school, starting in the fifth grade, distinguishing himself in physics and mathematics, graduating as the youngest and most able student in 1876. At the University of Uppsala, he was dissatisfied with the chief instructor of physics and the only faculty member who could have supervised him in chemistry, Per Teodor Cleve, so he left to study at the Physical Institute of the Swedish Academy of Sciences in Stockholm under the physicist Erik Edlund in 1881, his work focused on the conductivities of electrolytes. In 1884, based on this work, he submitted a 150-page dissertation on electrolytic conductivity to Uppsala for the doctorate.
It did not impress the professors, among whom was Cleve, he received a fourth-class degree, but upon his defense it was reclassified as third-class. Extensions of this work would earn him the 1903 Nobel Prize in Chemistry. Arrhenius put forth 56 theses in his 1884 dissertation, most of which would still be accepted today unchanged or with minor modifications; the most important idea in the dissertation was his explanation of the fact that solid crystalline salts disassociate into paired charged particles when dissolved, for which he would win the 1903 Nobel Prize in Chemistry. Arrhenius's explanation was that in forming a solution, the salt disassociates into charged particles, to which Michael Faraday had given the name ions many years earlier. Faraday's belief had been that ions were produced in the process of electrolysis, that is, an external direct current source of electricity was necessary to form ions. Arrhenius proposed that in the absence of an electric current, aqueous solutions of salts contained ions.
He thus proposed. The dissertation did not impress the professors at Uppsala, but Arrhenius sent it to a number of scientists in Europe who were developing the new science of physical chemistry, such as Rudolf Clausius, Wilhelm Ostwald, J. H. van't Hoff. They were far more impressed, Ostwald came to Uppsala to persuade Arrhenius to join his research team. Arrhenius declined, however, as he preferred to stay in Sweden for a while and had received an appointment at Uppsala. In an extension of his ionic theory Arrhenius proposed definitions for acids and bases, in 1884, he believed that acids were substances that produce hydrogen ions in solution and that bases were substances that produce hydroxide ions in solution. In 1885 Arrhenius next received a travel grant from the Swedish Academy of Sciences, which enabled him to study with Ostwald in Riga, with Friedrich Kohlrausch in Würzburg, with Ludwig Boltzmann in Graz and with van't Hoff in Amsterdam. In 1889 Arrhenius explained the fact that most reactions require added heat energy to proceed by formulating the concept of activation energy, an energy barrier that must be overcome before two molecules will react.
The Arrhenius equation gives the quantitative basis of the relationship between the activation energy and the rate at which a reaction proceeds. In 1891 he became a lecturer at the Stockholm University College, being promoted to professor of physics in 1895, rector in 1896, he was married twice, first to his former pupil Sofia Rudbeck, with whom he had one son Olof Arrhenius, to Maria Johansson, with whom he had two daughters and a son. About 1900, Arrhenius became involved in setting up the Nobel Prizes, he was elected a member of the Royal Swedish Academy of Sciences in 1901. For the rest of his life, he would be a member of the Nobel Committee on Physics and a de facto member of the Nobel Committee on Chemistry, he used his positions to attempt to deny them to his enemies. In 1901 Arrhenius was elected against strong opposition. In 1903 he became the first Swede to be awarded the Nobel Prize in chemistry. In 1905, upon the founding of the Nobel Institute for Physical Research at Stockholm, he was appointed rector of the institute, the position whe
Jacobus Henricus van 't Hoff
Jacobus Henricus "Henry" van't Hoff, Jr. was a Dutch physical chemist. A influential theoretical chemist of his time, van't Hoff was the first winner of the Nobel Prize in Chemistry, his pioneering work helped found the modern theory of chemical affinity, chemical equilibrium, chemical kinetics, chemical thermodynamics. In his 1874 pamphlet van't Hoff formulated the theory of the tetrahedral carbon atom and laid the foundations of stereochemistry. In 1875, he predicted the correct structures of allenes and cumulenes as well as their axial chirality, he is widely considered one of the founders of physical chemistry as the discipline is known today. The third of seven children, van't Hoff was born in Rotterdam, Netherlands, 30 August 1852, his father was Jacobus Henricus van't Hoff, Sr. a physician, his mother was Alida Kolff van't Hoff. From a young age, he was interested in science and nature, took part in botanical excursions. In his early school years, he showed a strong interest in philosophy.
He considered Lord Byron to be his idol. Against the wishes of his father, van't Hoff chose to study chemistry. First, he enrolled at Delft University of Technology in September 1869, studied until 1871, when he passed his final exam on 8 July and obtained a degree of chemical technologist, he passed all his courses in two years. He enrolled at University of Leiden to study chemistry, he studied in Bonn, with Friedrich Kekulé and in Paris with C. A. Wurtz, he received his doctorate under Eduard Mulder at the University of Utrecht in 1874. In 1878, van't Hoff married Johanna Francina Mees, they had two daughters, Johanna Francina and Aleida Jacoba, two sons, Jacobus Henricus van't Hoff III and Govert Jacob. Van't Hoff died on 1 March 1911, at Steglitz, near Berlin, of tuberculosis. Van't Hoff earned his earliest reputation in the field of organic chemistry. In 1874, he accounted for the phenomenon of optical activity by assuming that the chemical bonds between carbon atoms and their neighbors were directed towards the corners of a regular tetrahedron.
This three-dimensional structure accounted for the isomers found in nature. He shares credit for this with the French chemist Joseph Le Bel, who independently came up with the same idea. Three months before his doctoral degree was awarded, van't Hoff published this theory, which today is regarded as the foundation of stereochemistry, first in a Dutch pamphlet in the fall of 1874, in the following May in a small French book entitled La chimie dans l'espace. A German translation appeared in 1877, at a time when the only job van't Hoff could find was at the Veterinary School in Utrecht. In these early years his theory was ignored by the scientific community, was criticized by one prominent chemist, Hermann Kolbe. Kolbe wrote: "A Dr. J. H. van ’t Hoff of the Veterinary School at Utrecht has no liking for exact chemical investigation. He has considered it more convenient to mount Pegasus and to proclaim in his ‘La chimie dans l’espace’ how, in his bold flight to the top of the chemical Parnassus, the atoms appeared to him to be arranged in cosmic space."
However, by about 1880 support for van't Hoff's theory by such important chemists as Johannes Wislicenus and Viktor Meyer brought recognition. In 1884, van't Hoff published his research on chemical kinetics, titled Études de Dynamique chimique, in which he described a new method for determining the order of a reaction using graphics and applied the laws of thermodynamics to chemical equilibria, he introduced the modern concept of chemical affinity. In 1886, he showed a similarity between the behaviour of dilute gases. In 1887, he and German chemist Wilhelm Ostwald founded an influential scientific magazine named Zeitschrift für physikalische Chemie, he worked on Svante Arrhenius's theory of the dissociation of electrolytes and in 1889 provided physical justification for the Arrhenius equation. In 1896, he became a professor at the Prussian Academy of Sciences in Berlin, his studies of the salt deposits at Stassfurt were an important contribution to Prussia's chemical industry. Van't Hoff became a lecturer in physics at the Veterinary College in Utrecht.
He worked as a professor of chemistry and geology at the University of Amsterdam for 18 years before becoming the chairman of the chemistry department. In 1896, van't Hoff moved to Germany, where he finished his career at the University of Berlin in 1911. In 1901, he received the first Nobel Prize in Chemistry for his work with solutions, his work showed that dilute solutions follow mathematical laws that resemble the laws describing the behavior of gases. In 1885, van't Hoff was appointed as a member of the Royal Netherlands Academy of Sciences. Other distinctions include honorary doctorates from Harvard and Yale, Victoria University, the University of Manchester, University of Heidelberg, he was awarded the Davy Medal of the Royal Society in 1893, elected a Foreign Member of the Royal Society in 1897. He was awarded the Helmholtz Medal of the Prussian Academy of Sciences and appointed Chevalier de la Légion d'honneur and Senator der Kaiser-Wilhelm-Gesellschaft. Van't Hoff became an honorary member of the British Chemical Society in London, the Royal Dutch Academy of Sciences, American Chemical Society, Borlase's Chemistry Society.
And the Académie des Scienc
Biochemist
Biochemists are scientists that are trained in biochemistry. Biochemists study chemical processes and chemical transformations in living organisms. Biochemists study DNA, proteins and cell parts; the word "biochemist" is a portmanteau of "biological chemist." Biochemists research how certain chemical reactions happen in cells and tissues and observe and record the effects of products in food additives and medicines. Biochemist researchers focus on planning and conducting research experiments for developing new products, updating existing products and analyzing said products, it is the responsibility of a biochemist to present their research findings and create grant proposals to obtain funds for future research. Biochemists study aspects of the immune system, the expressions of genes, isolating and synthesizing different products, mutations that lead to cancers, manage laboratory teams and monitor laboratory work. Biochemists have to have the capabilities of designing and building laboratory equipment and devise new methods of producing correct results for products.
The most common industry role is the development of biochemical processes. Identifying substances' chemical and physical properties in biological systems is of great importance, can be carried out by doing various types of analysis. Biochemists must prepare technical reports after collecting and summarizing the information and trends found. In biochemistry, researchers break down complicated biological systems into their component parts, they study the effects of foods, drugs and other substances on living tissues. About 75 % work in either applied research; each of these fields allows specialization. Biochemists in the field of agriculture research the interactions between herbicides with plants, they examine the relationships of compounds, determining their ability to inhibit growth, evaluate the toxicological effects surrounding life. Biochemists prepare pharmaceutical compounds for commercial distribution. Modern biochemistry is considered a sub-discipline of the biological sciences, due to its increased reliance on, training, in accord with modern molecular biology.
Before the term biochemist was formally recognized, initial studies were performed by those trained in basic chemistry, but by those trained as physicians. Some of the job skills and abilities that one needs to attain to be successful in this field of work include science, reading comprehension and critical thinking; these skills are critical because of the nature of the experimental techniques that are used as well as the need to convey orally and written the trends found in research. A degree in biochemistry or a related science such as chemistry is the minimum requirement for any work in this field; this is sufficient for a position in academic settings. A Ph. D. is required to pursue or direct independent research. To advance further in commercial environments, one may need to acquire skills in management. Biochemists must pass a qualifying exam or a preliminary exam to continue their studies when receiving a Ph. D. in biochemistry. Biochemistry requires an understanding of inorganic chemistry.
All types of chemistry are required, with emphasis on biochemistry, organic chemistry and physical chemistry. Basic classes in biology, including microbiology, molecular biology, molecular genetics, cell biology, genomics, are focused on; some instruction in experimental techniques and quantification is part of most curricula. In the private industries for businesses, it is imperative to possess strong business management skills as well as communication skills. Biochemists must be familiar with regulatory rules and management techniques. Due to the reliance on most principles of the basic science of Biochemistry, early contemporary physicians were informally qualified to perform research on their own in this field. Biochemists are employed in the life sciences, where they work in the pharmaceutical or biotechnology industry in a research role, they are employed in academic institutes, where in addition to pursuing their research they may be involved with teaching undergraduates, training graduate students, collaborating with post-doctoral fellows.
The U. S. Bureau of Labor Statistics estimates that jobs in the biochemist, combined with the statistics of biophysicists, field would increase by 31% between 2004 and 2014 because of the demand in medical research and development of new drugs and products, the preservation of the environment; because of a biochemists' background in both biology and chemistry, they may be employed in the medical, industrial and environmental fields. More than half of the biological scientists are employed by the Federal State and local governments; the field of medicine includes nutrition, genetics and pharmacology.
Crystallization
Crystallization is the process by which a solid forms, where the atoms or molecules are organized into a structure known as a crystal. Some of the ways by which crystals form are precipitating from a solution, freezing, or more deposition directly from a gas. Attributes of the resulting crystal depend on factors such as temperature, air pressure, in the case of liquid crystals, time of fluid evaporation. Crystallization occurs in two major steps; the first is nucleation, the appearance of a crystalline phase from either a supercooled liquid or a supersaturated solvent. The second step is known as crystal growth, the increase in the size of particles and leads to a crystal state. An important feature of this step is that loose particles form layers at the crystal's surface lodge themselves into open inconsistencies such as pores, etc; the majority of minerals and organic molecules crystallize and the resulting crystals are of good quality, i.e. without visible defects. However, larger biochemical particles, like proteins, are difficult to crystallize.
The ease with which molecules will crystallize depends on the intensity of either atomic forces, intermolecular forces or intramolecular forces. Crystallization is a chemical solid–liquid separation technique, in which mass transfer of a solute from the liquid solution to a pure solid crystalline phase occurs. In chemical engineering, crystallization occurs in a crystallizer. Crystallization is therefore related to precipitation, although the result is not amorphous or disordered, but a crystal; the crystallization process consists of two major events and crystal growth which are driven by thermodynamic properties as well as chemical properties. In crystallization Nucleation is the step where the solute molecules or atoms dispersed in the solvent start to gather into clusters, on the microscopic scale, that become stable under the current operating conditions; these stable clusters constitute the nuclei. Therefore, the clusters need to reach a critical size; such critical size is dictated by many different factors.
It is at the stage of nucleation that the atoms or molecules arrange in a defined and periodic manner that defines the crystal structure — note that "crystal structure" is a special term that refers to the relative arrangement of the atoms or molecules, not the macroscopic properties of the crystal, although those are a result of the internal crystal structure. The crystal growth is the subsequent size increase of the nuclei that succeed in achieving the critical cluster size. Crystal growth is a dynamic process occurring in equilibrium where solute molecules or atoms precipitate out of solution, dissolve back into solution. Supersaturation is one of the driving forces of crystallization, as the solubility of a species is an equilibrium process quantified by Ksp. Depending upon the conditions, either nucleation or growth may be predominant over the other, dictating crystal size. Many compounds have the ability to crystallize with some having different crystal structures, a phenomenon called polymorphism.
Each polymorph is in fact a different thermodynamic solid state and crystal polymorphs of the same compound exhibit different physical properties, such as dissolution rate, melting point, etc. For this reason, polymorphism is of major importance in industrial manufacture of crystalline products. Additionally, crystal phases can sometimes be interconverted by varying factors such as temperature. There are many examples of natural process. Geological time scale process examples include: Natural crystal formation. Human time scale process examples include: Snow flakes formation. Crystal formation can be divided into two types, where the first type of crystals are composed of a cation and anion known as a salt, such as sodium acetate; the second type of crystals are composed for example menthol. Crystal formation can be achieved by various methods, such as: cooling, addition of a second solvent to reduce the solubility of the solute, solvent layering, changing the cation or anion, as well as other methods.
The formation of a supersaturated solution does not guarantee crystal formation, a seed crystal or scratching the glass is required to form nucleation sites. A typical laboratory technique for crystal formation is to dissolve the solid in a solution in which it is soluble at high temperatures to obtain supersaturation; the hot mixture is filtered to remove any insoluble impurities. The filtrate is allowed to cool. Crystals that form are filtered and washed with a solvent in which they are not soluble, but is miscible with the mother liquor; the process is repeated to increase the purity in a technique known as recrystallization. For biological molecules in which the solvent channels continue to be present to retain the three dimensional structure intact, microbatch crystallization under oil and vapor diffusion methods have been the common methods. Equipment for the main industrial processes for crystallization. Tank crystallizers. Tank crystallization is an old method still used in some specialized cases.
Saturated solutions, in tank crystallization, are allowed to cool in open tanks. After a period of time the mother liquo
