1.
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
2.
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
3.
Life
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Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguous and may or may not define viruses, viroids, biology is the primary science concerned with the study of life, although many other sciences are involved. The definition of life is controversial, the current definition is that organisms maintain homeostasis, are composed of cells, undergo metabolism, can grow, adapt to their environment, respond to stimuli, and reproduce. However, many other definitions have been proposed, and there are some borderline cases. Modern definitions are more complex, with input from a diversity of scientific disciplines, biophysicists have proposed many definitions based on chemical systems, there are also some living systems theories, such as the Gaia hypothesis, the idea that the Earth itself is alive. Another theory is that life is the property of systems, and yet another is elaborated in complex systems biology. Abiogenesis describes the process of life arising from non-living matter. Properties common to all organisms include the need for certain chemical elements to sustain biochemical functions. Life on Earth first appeared as early as 4.28 billion years ago, soon after ocean formation 4.41 billion years ago, Earths current life may have descended from an RNA world, although RNA-based life may not have been the first. The mechanism by which began on Earth is unknown, though many hypotheses have been formulated and are often based on the Miller–Urey experiment. The earliest known forms are microfossils of bacteria. In July 2016, scientists reported identifying a set of 355 genes believed to be present in the last universal ancestor of all living organisms. Since its primordial beginnings, life on Earth has changed its environment on a time scale. To survive in most ecosystems, life must often adapt to a range of conditions. Some microorganisms, called extremophiles, thrive in physically or geochemically extreme environments that are detrimental to most other life on Earth, Aristotle was the first person to classify organisms. Later, Carl Linnaeus introduced his system of nomenclature for the classification of species. Eventually new groups and categories of life were discovered, such as cells and microorganisms, cells are sometimes considered the smallest units and building blocks of life. There are two kinds of cells, prokaryotic and eukaryotic, both of which consist of cytoplasm enclosed within a membrane and contain many such as proteins
4.
Microscope
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A microscope is an instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy, microscopic means invisible to the eye unless aided by a microscope. There are many types of microscopes, the most common is the optical microscope, which uses light to image the sample. Other major types of microscopes are the microscope, the ultramicroscope. The earliest microscopes were single lens magnifying glasses with limited magnification which date at least as far back as the wide use of lenses in eyeglasses in the 13th century. Compound microscopes, which combine an objective lens with an eyepiece to view a real image, the actual inventor of the compound microscope is unknown although many claims have been made over the years. These include what may be a claim by the son of Zacharias Janssen that his father invented the microscope and telescope as early as 1590. Historians note the compound microscope did not appear in the Netherlands until the 1620s, giovanni Faber coined the name microscope for the compound microscope Galileo submitted to the Accademia dei Lincei in 1625. The first detailed account of the construction of living tissue based on the use of a microscope did not appear until 1644, in Giambattista Odiernas Locchio della mosca. It was not until the 1660s and 1670s that the microscope was used extensively for research in Italy, marcello Malpighi in Italy began the analysis of biological structures, beginning with the lungs. Robert Hookes Micrographia had an impact, largely because of its impressive illustrations. A significant contribution came from Antonie van Leeuwenhoek who achieved up to 300 times magnification using a single lens microscope. He sandwiched a very small glass ball lens between the holes in two metal plates riveted together, and with a needle attached to mount the specimen. Then, Van Leeuwenhoek re-discovered red blood cells and spermatozoa, on 9 October 1676, he reported the discovery of micro-organisms. The performance of light microscopy depends as much on how the sample is illuminated as on how it is observed, early instruments were limited until this principle was fully appreciated and developed, and until electric lamps were available as light sources. In 1893 August Köhler developed a key principle of sample illumination, Köhler illumination and this method of sample illumination produces even lighting and overcomes the limited contrast and resolution imposed by early techniques of sample illumination. In the early 20th century a significant alternative to light microscopy was developed, ernst Ruska started development of the first electron microscope in 1931 which was the transmission electron microscope. The transmission electron microscope works on the principle as an optical microscope but uses electrons in the place of light
5.
Optical microscope
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The optical microscope, often referred to as light microscope, is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. Optical microscopes are the oldest design of microscope and were invented in their present compound form in the 17th century. Basic optical microscopes can be simple, although there are many complex designs which aim to improve resolution. The image from a microscope can be captured by normal light-sensitive cameras to generate a micrograph. Originally images were captured by photographic film but modern developments in CMOS, purely digital microscopes are now available which use a CCD camera to examine a sample, showing the resulting image directly on a computer screen without the need for eyepieces. Alternatives to optical microscopy which do not use visible light include scanning electron microscopy, there are two basic types of optical microscopes, simple microscopes and compound microscopes. A simple microscope is one which uses a lens for magnification. A compound microscope uses several lenses to enhance the magnification of an object, the vast majority of modern research microscopes are compound microscopes while some cheaper commercial digital microscopes are simple single lens microscopes. Compound microscopes can be divided into a variety of other types of microscopes which differ in their optical configurations, cost. A simple microscope uses a lens or set of lenses to enlarge an object through angular magnification alone, the use of a single convex lens or groups of lenses are still found in simple magnification devices such as the magnifying glass, loupes, and eyepieces for telescopes and microscopes. A compound microscope uses a close to the object being viewed to collect light which focuses a real image of the object inside the microscope. That image is magnified by a second lens or group of lenses that gives the viewer an enlarged inverted virtual image of the object. The use of a compound objective/eyepiece combination allows for higher magnification. Common compound microscopes often feature exchangeable objective lenses, allowing the user to quickly adjust the magnification, a compound microscope also enables more advanced illumination setups, such as phase contrast. There are many variants of the optical microscope design for specialized purposes. Comparison microscope, which has two light paths allowing direct comparison of two samples via one image in each eye. Inverted microscope, for studying samples from below, useful for cell cultures in liquid, student microscope, designed for low cost, durability, and ease of use. Polarizing microscope, similar to the petrographic microscope, phase contrast microscope, which applies the phase contrast illumination method
6.
Robert Hooke
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Robert Hooke FRS was an English natural philosopher, architect and polymath. Allan Chapman has characterised him as Englands Leonardo, Robert Gunthers Early Science in Oxford, a history of science in Oxford during the Protectorate, Restoration and Age of Enlightenment, devotes five of its fourteen volumes to Hooke. Hooke studied at Wadham College, Oxford during the Protectorate where he became one of a tightly knit group of ardent Royalists led by John Wilkins. Here he was employed as an assistant to Thomas Willis and to Robert Boyle and he built some of the earliest Gregorian telescopes and observed the rotations of Mars and Jupiter. In 1665 he inspired the use of microscopes for scientific exploration with his book, based on his microscopic observations of fossils, Hooke was an early proponent of biological evolution. Much of Hookes scientific work was conducted in his capacity as curator of experiments of the Royal Society, much of what is known of Hookes early life comes from an autobiography that he commenced in 1696 but never completed. Richard Waller mentions it in his introduction to The Posthumous Works of Robert Hooke, the work of Waller, along with John Wards Lives of the Gresham Professors and John Aubreys Brief Lives, form the major near-contemporaneous biographical accounts of Hooke. Robert Hooke was born in 1635 in Freshwater on the Isle of Wight to John Hooke, Robert was the last of four children, two boys and two girls, and there was an age difference of seven years between him and the next youngest. Their father John was a Church of England priest, the curate of Freshwaters Church of All Saints, Robert Hooke was expected to succeed in his education and join the Church. John Hooke also was in charge of a school, and so was able to teach Robert. He was a Royalist and almost certainly a member of a group who went to pay their respects to Charles I when he escaped to the Isle of Wight, Robert, too, grew up to be a staunch monarchist. As a youth, Robert Hooke was fascinated by observation, mechanical works and he dismantled a brass clock and built a wooden replica that, by all accounts, worked well enough, and he learned to draw, making his own materials from coal, chalk and ruddle. Hooke quickly mastered Latin and Greek, made study of Hebrew. Here, too, he embarked on his study of mechanics. It appears that Hooke was one of a group of students whom Busby educated in parallel to the work of the school. Contemporary accounts say he was not much seen in the school, in 1653, Hooke secured a choristers place at Christ Church, Oxford. He was employed as an assistant to Dr Thomas Willis. There he met the natural philosopher Robert Boyle, and gained employment as his assistant from about 1655 to 1662, constructing, operating and he did not take his Master of Arts until 1662 or 1663
7.
Cork (material)
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Cork is an impermeable buoyant material, the phellem layer of bark tissue that is harvested for commercial use primarily from Quercus suber, which is endemic to southwest Europe and northwest Africa. The montado landscape of Portugal produces approximately half of cork harvested annually worldwide, Cork was examined microscopically by Robert Hooke, which led to his discovery and naming of the cell. There are about 2,200,000 hectares of cork forest worldwide, 34% in Portugal and 27% in Spain. Annual production is about 200,000 tons,49. 6% from Portugal,30. 5% from Spain,5. 8% from Morocco,4. 9% from Algeria,3. 5% from Tunisia,3. 1% Italy, and 2. 6% from France. Once the trees are about 25 years old the cork is traditionally stripped from the trunks every nine years, the trees live for about 300 years. The cork industry is regarded as environmentally friendly. Cork production is considered sustainable because the cork tree is not cut down to obtain cork. The tree continues to live and grow, the sustainability of production and the easy recycling of cork products and by-products are two of its most distinctive aspects. Cork Oak forests also prevent desertification and are a habitat in the Iberian Peninsula. The Corticeira Amorim’s study, in particular, was developed by PricewaterhouseCoopers, results concluded that, concerning the emission of greenhouse gases, each plastic stopper released 10 times more CO2, whilst an aluminium stopper releases 26 times more CO2 than does a cork stopper. The Cork Oak is unrelated to the trees, which have corky bark but are not used for cork production. Cork is extracted only from early May to late August, when the cork can be separated from the tree without causing permanent damage, when the tree reaches 25–30 years of age and about 24 in in circumference, the cork can be removed for the first time. However, this first harvest almost always produces poor quality or male cork, bark from initial harvests can be used to make flooring, shoes, insulation and other industrial products. Subsequent extractions usually occur at intervals of 9 years, though it can take up to 13 for the cork to reach an acceptable size. If the product is of quality it is known as gentle cork. The workers who specialize in removing the cork are known as extractors and this is the most delicate phase of the work because, even though cutting the cork requires quite a bit of strength, the extractor must not damage the underlying phellogen or the tree will be harmed. To free the cork from the tree, the extractor pushes the handle of the axe into the rulers, a good extractor needs to use a firm but precise touch in order to free a large amount of cork without damaging the product or tree. These freed portions of the cork are called planks, the planks are usually carried off by hand since cork forests are rarely accessible to vehicles
8.
Rudolf Virchow
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Rudolf Ludwig Carl Virchow was a German physician, anthropologist, pathologist, prehistorian, biologist, writer, editor, and politician, known for his advancement of public health. He is known as the father of modern pathology because his work helped to discredit humourism and he is also known as the founder of social medicine and veterinary pathology, and to his colleagues, the Pope of medicine. Born and raised in Schievelbein as a child of a working-class family. Dissuaded by his voice, he abandoned his initial interest in theology. With special military scholarship, he earned his degree from Friedrich-Wilhelms Institute under the tutelage of Johannes Peter Müller. He worked at the Charité hospital under Robert Froriep, whom he succeeded as the prosector. Although he failed to contain the 1847–1848 typhus epidemic in Upper Silesia, his report laid the foundation for health in Germany. From it, he coined a well known aphorism, Medicine is a social science and he participated in the Revolution of 1848, which led to his expulsion from Charité the next year. He published a newspaper Die medicinische Reform during this period to disseminate his social and political ideas and he took the first Chair of Pathological Anatomy at the University of Würzburg in 1849. After five years, Charité invited him back to direct its newly built Institute for Pathology, the campus of Charité is now named Campus Virchow Klinikum. He cofounded the political party Deutsche Fortschrittspartei, by which he was elected to the Prussian House of Representatives and his opposition to Otto von Bismarcks financial policy resulted in an anecdotal Sausage Duel between the two. But he ardently supported Bismarck in his campaigns, the social revolution he himself named as Kulturkampf. A prolific writer, his writings alone exceeded 2,000 in number. Among his books, Cellular Pathology published in 1858 is regarded as the root of modern pathology and this work also popularised the third dictum in cell theory, Omnis cellula e cellula, although his idea originated in 1855. He founded journals such as Archiv für pathologische Anatomie und Physiologie und für klinische Medizin, the latter is published by German Anthropological Association and the Berlin Society for Anthropology, Ethnology and Prehistory, the societies of which he also founded. Virchow was the first to describe and give names of diseases such as leukemia, chordoma, ochronosis, embolism. He coined scientific terms, chromatin, agenesis, parenchyma, osteoid, amyloid degeneration and his description of the transmission cycle of a roundworm Trichinella spiralis established the importance of meat inspection, which was started in Berlin. He developed the first systematic method of autopsy involving surgery of all body parts, a number of medical terms are named after him, including Virchows node, Virchow–Robin spaces, Virchow–Seckel syndrome, and Virchows triad
9.
Fluorescence microscope
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The specimen is illuminated with light of a specific wavelength which is absorbed by the fluorophores, causing them to emit light of longer wavelengths. The illumination light is separated from the much weaker emitted fluorescence through the use of an emission filter. Typical components of a microscope are a light source, the excitation filter, the dichroic mirror. The filters and the dichroic beamsplitter are chosen to match the spectral excitation and emission characteristics of the used to label the specimen. In this manner, the distribution of a fluorophore is imaged at a time. Multi-color images of types of fluorophores must be composed by combining several single-color images. Most fluorescence microscopes in use are epifluorescence microscopes, where excitation of the fluorophore and these microscopes are widely used in biology and are the basis for more advanced microscope designs, such as the confocal microscope and the total internal reflection fluorescence microscope. The majority of fluorescence microscopes, especially used in the life sciences, are of the epifluorescence design shown in the diagram. Light of the wavelength is focused on the specimen through the objective lens. Fluorescence microscopy requires intense, near-monochromatic, illumination which some widespread light sources, four main types of light source are used, including xenon arc lamps or mercury-vapor lamps with an excitation filter, lasers, supercontinuum sources, and high-power LEDs. In order for a sample to be suitable for fluorescence microscopy it must be fluorescent, there are several methods of creating a fluorescent sample, the main techniques are labelling with fluorescent stains or, in the case of biological samples, expression of a fluorescent protein. Alternatively the intrinsic fluorescence of a sample can be used, as a result, there is a diverse range of techniques for fluorescent staining of biological samples. Many fluorescent stains have been designed for a range of biological molecules, some of these are small molecules which are intrinsically fluorescent and bind a biological molecule of interest. Major examples of these are nucleic acid stains like DAPI and Hoechst and DRAQ5 and DRAQ7 which all bind the minor groove of DNA, others are drugs or toxins which bind specific cellular structures and have been derivatised with a fluorescent reporter. A major example of class of fluorescent stain is phalloidin which is used to stain actin fibres in mammalian cells. Immunofluorescence is a technique which uses the specific binding of an antibody to its antigen in order to label specific proteins or other molecules within the cell. A sample is treated with an antibody specific for the molecule of interest. A fluorophore can be conjugated to the primary antibody
10.
Phase-contrast microscopy
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Phase-contrast microscopy is an optical-microscopy technique that converts phase shifts in light passing through a transparent specimen to brightness changes in the image. Phase shifts themselves are invisible, but become visible when shown as brightness variations, when light waves travel through a medium other than vacuum, interaction with the medium causes the wave amplitude and phase to change in a manner dependent on properties of the medium. Changes in amplitude arise from the scattering and absorption of light, photographic equipment and the human eye are only sensitive to amplitude variations. Without special arrangements, phase changes are therefore invisible, yet, phase changes often carry important information. Phase-contrast microscopy is particularly important in biology and it reveals many cellular structures that are not visible with a simpler bright-field microscope, as exemplified in the figure. These structures were visible to earlier microscopists by staining, but this required additional preparation. The phase-contrast microscope made it possible for biologists to study living cells, after its invention in the early 1930s, phase-contrast microscopy proved to be such an advancement in microscopy, that its inventor Frits Zernike was awarded the Nobel prize in 1953. The basic principle to making phase changes visible in phase-contrast microscopy is to separate the light from the specimen-scattered light. The ring-shaped illuminating light that passes the condenser annulus is focused on the specimen by the condenser, some of the illuminating light is scattered by the specimen. The remaining light is unaffected by the specimen and forms the background light, when observing an unstained biological specimen, the scattered light is weak and typically phase-shifted by −90° relative to the background light. This leads to the foreground and background having nearly the same intensity, first, the background light is phase-shifted by −90° by passing it through a phase-shift ring, which eliminates the phase difference between the background and the scattered light rays. Some of the light will be phase-shifted and dimmed by the rings. The above describes negative phase contrast, in its positive form, the background light is instead phase-shifted by +90°. The background light will thus be 180° out of relative to the scattered light. The scattered light will then be subtracted from the light to form an image with a darker foreground. The success of the phase-contrast microscope has led to a number of subsequent phase-imaging methods, in 1952 Georges Nomarski patented what is today known as differential interference contrast microscopy. It enhances contrast by creating artificial shadows, as if the object is illuminated from the side, but DIC microscopy and phase contrast microscopy both use polarized light, which is unsuitable when the object or its container alter polarization. With the growing use of polarizing plastic containers in cell biology, DIC microscopy is increasingly replaced by Hoffman modulation contrast microscopy, traditional phase-contrast methods enhance contrast optically, blending brightness and phase information in single image
11.
Cytometry
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Cytometry is the measurement of the characteristics of cells. Cytometry is used to characterize and count blood cells in blood tests such as the complete blood count. Image cytometery is the oldest form of cytometry, image cytometers operate by statically imaging a large number of cells using optical microscopy. Prior to analysis, cells are stained to enhance contrast or to detect specific molecules by labeling these with fluorochromes. Traditionally, cells are viewed within a hemocytometer to aid manual counting, since the introduction of the digital camera, in the mid-1990s, the automation level of image cytometers has steadily increased. This has led to the availability of automated image cytometers. Due to the difficulties of automating microscopy, the flow cytometer has since the mid-1950s been the dominating cytometric device. Flow cytometers operate by aligning single cells using flow techniques, the cells are characterized optically or by the use of an electrical impedance method called the Coulter principle. To detect specific molecules when optically characterized, cells are in most cases stained with the type of fluorochromes that are used by image cytometers. Flow cytometers generally provide less data than image cytometers, but have a higher throughput. Cell sorters are flow cytometers capable of sorting cells according to their characteristics, the sorting is achieved by using technology similar to what is used in inkjet printers. The fluid stream is broken up into droplets by a mechanical vibration, the droplets are then electrically charged according to the characteristics of the cell contained within the droplet. Depending on their charge, the droplets are deflected by an electric field into different containers. Conventional flow and image cytometers have the disadvantage of not being able to observe cells over time, the rapid decrease in the cost of digitally storing and processing video information has led to the development of image cytometers which monitor cultured cells using time-lapse video recordings. After recording, the video is computer processed to track cytometric parameters over time, a key characteristic of time-lapse cytometers is their use of non heat-generating light sources such as light-emitting diodes. This allows a time-lapse cytometer to be placed inside a cell culture incubator to facilitate continuous observation of cellular processes without heat building up inside the incubator. The early history of cytometry is closely associated with the development of the blood cell counting, until the 1950s the hemocytometer was the standard method to count blood cells. In blood cell counting applications the hemocytometer has now replaced by electronic cell counters
This article incorporates public domain material from the NCBI document "Science Primer".
This article incorporates 
