Chinese herbology ( traditional Chinese : 中藥學 ; simplified Chinese : 中药学 ; pinyin : zhōngyào xué ) is the theory of traditional Chinese herbal therapy, which accounts for the majority of treatments in traditional Chinese medicine (TCM). A Nature editorial described TCM as "fraught with pseudoscience ", and said that the most obvious reason why it has not delivered many cures is that the majority of its treatments have no logical mechanism of action .
142-670: The Bencao gangmu , known in English as the Compendium of Materia Medica or Great Pharmacopoeia , is an encyclopedic gathering of medicine, natural history, and Chinese herbology compiled and edited by Li Shizhen and published in the late 16th century, during the Ming dynasty . Its first draft was completed in 1578 and printed in Nanjing in 1596. The Compendium lists the materia medica of traditional Chinese medicine known at
284-535: A last universal common ancestor that lived about 3.5 billion years ago . Geologists have developed a geologic time scale that divides the history of the Earth into major divisions, starting with four eons ( Hadean , Archean , Proterozoic , and Phanerozoic ), the first three of which are collectively known as the Precambrian , which lasted approximately 4 billion years. Each eon can be divided into eras, with
426-440: A lipid bilayer , including cholesterols that sit between phospholipids to maintain their fluidity at various temperatures. Cell membranes are semipermeable , allowing small molecules such as oxygen, carbon dioxide, and water to pass through while restricting the movement of larger molecules and charged particles such as ions . Cell membranes also contain membrane proteins , including integral membrane proteins that go across
568-443: A nucleus , and prokaryotic cells, which do not. Prokaryotes are single-celled organisms such as bacteria , whereas eukaryotes can be single-celled or multicellular. In multicellular organisms , every cell in the organism's body is derived ultimately from a single cell in a fertilized egg . Every cell is enclosed within a cell membrane that separates its cytoplasm from the extracellular space . A cell membrane consists of
710-508: A number of shapes , ranging from spheres to rods and spirals . Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats . Bacteria inhabit soil, water, acidic hot springs , radioactive waste , and the deep biosphere of the Earth's crust . Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only about 27 percent of
852-631: A bland ( 淡 ) flavor). Each of the Five Flavors corresponds to one of the zàng organs , which in turn corresponds to one of the Five Phases : A flavor implies certain properties and presumed therapeutic "actions" of a substance: saltiness "drains downward and softens hard masses"; sweetness is "supplementing, harmonizing, and moistening"; pungent substances are thought to induce sweat and act on qi and blood ; sourness tends to be astringent ( 澀 ; 涩 ) in nature; bitterness "drains heat , purges
994-474: A cell's size, shape, membrane potential , metabolic activity , and responsiveness to signals, which are largely due to highly controlled modifications in gene expression and epigenetics . With a few exceptions, cellular differentiation almost never involves a change in the DNA sequence itself. Thus, different cells can have very different physical characteristics despite having the same genome . Morphogenesis, or
1136-408: A chemical (e.g., nitrous acid , benzopyrene ) or radiation (e.g., x-ray , gamma ray , ultraviolet radiation , particles emitted by unstable isotopes). Mutations can lead to phenotypic effects such as loss-of-function, gain-of-function , and conditional mutations. Some mutations are beneficial, as they are a source of genetic variation for evolution. Others are harmful if they were to result in
1278-432: A copy to the Ming dynasty emperor, who saw it but did not pay much attention. Further editions were then published in 1603, 1606, 1640, and then in many editions, with increasing numbers of illustrations, down to the 21st century. The text consists of 1,892 entries, each entry with its own name called a gang . The mu in the title refers to the synonyms of each name. The Compendium has 53 volumes in total: The text
1420-1233: A few archaea have very different shapes, such as the flat and square cells of Haloquadratum walsbyi . Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes involved in transcription and translation . Other aspects of archaeal biochemistry are unique, such as their reliance on ether lipids in their cell membranes , including archaeols . Archaea use more energy sources than eukaryotes: these range from organic compounds , such as sugars, to ammonia , metal ions or even hydrogen gas . Salt-tolerant archaea (the Haloarchaea ) use sunlight as an energy source, and other species of archaea fix carbon , but unlike plants and cyanobacteria , no known species of archaea does both. Archaea reproduce asexually by binary fission , fragmentation , or budding ; unlike bacteria, no known species of Archaea form endospores . The first observed archaea were extremophiles , living in extreme environments, such as hot springs and salt lakes with no other organisms. Improved molecular detection tools led to
1562-562: A few trials exist that are considered to have adequate methodology by scientific standards. Proof of effectiveness is poorly documented or absent. A 2016 Cochrane review found "insufficient evidence that Chinese Herbal Medicines were any more or less effective than placebo or hormonal therapy" for the relief of menopause related symptoms. A 2012 Cochrane review found no difference in decreased mortality for SARS patients when Chinese herbs were used alongside Western medicine versus Western medicine exclusively. A 2010 Cochrane review found there
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#17327717706471704-403: A final electron acceptor, which is usually the oxidized form of NADP , which is reduced to NADPH, a process that takes place in a protein complex called photosystem I (PSI). The transport of electrons is coupled to the movement of protons (or hydrogen) from the stroma to the thylakoid membrane, which forms a pH gradient across the membrane as hydrogen becomes more concentrated in the lumen than in
1846-776: A granular or powdered form. Herbal extracts, similar to patent medicines, are easier and more convenient for patients to take. The industry extraction standard is 5:1, meaning for every five pounds of raw materials, one pound of herbal extract is derived. There are several different methods to classify traditional Chinese medicinals: The Four Natures are: hot ( 熱 ; 热 ), warm ( 溫 ; 温 ), cool ( 涼 ), cold ( 寒 ) or neutral ( 平 ). Hot and warm herbs are used to treat cold diseases, while cool and cold herbs are used to treat hot diseases. The Five Flavors, sometimes also translated as Five Tastes , are: acrid/pungent ( 辛 ), sweet ( 甘 ), bitter ( 苦 ), sour ( 酸 ), and salty ( 鹹 ; 咸 ). Substances may also have more than one flavor, or none (i.e.,
1988-769: A loss of function of genes needed for survival. Gene expression is the molecular process by which a genotype encoded in DNA gives rise to an observable phenotype in the proteins of an organism's body. This process is summarized by the central dogma of molecular biology , which was formulated by Francis Crick in 1958. According to the Central Dogma, genetic information flows from DNA to RNA to protein. There are two gene expression processes: transcription (DNA to RNA) and translation (RNA to protein). The regulation of gene expression by environmental factors and during different stages of development can occur at each step of
2130-417: A more successful evolutionary theory based on natural selection ; similar reasoning and evidence led Alfred Russel Wallace to independently reach the same conclusions. The basis for modern genetics began with the work of Gregor Mendel in 1865. This outlined the principles of biological inheritance. However, the significance of his work was not realized until the early 20th century when evolution became
2272-457: A new cycle. In contrast to mitosis, meiosis results in four haploid daughter cells by undergoing one round of DNA replication followed by two divisions. Homologous chromosomes are separated in the first division ( meiosis I ), and sister chromatids are separated in the second division ( meiosis II ). Both of these cell division cycles are used in the process of sexual reproduction at some point in their life cycle. Both are believed to be present in
2414-409: A process known as allopatric speciation . A phylogeny is an evolutionary history of a specific group of organisms or their genes. It can be represented using a phylogenetic tree , a diagram showing lines of descent among organisms or their genes. Each line drawn on the time axis of a tree represents a lineage of descendants of a particular species or population. When a lineage divides into two, it
2556-408: A region of deoxyribonucleic acid (DNA) that carries genetic information that controls form or function of an organism. DNA is composed of two polynucleotide chains that coil around each other to form a double helix . It is found as linear chromosomes in eukaryotes , and circular chromosomes in prokaryotes . The set of chromosomes in a cell is collectively known as its genome . In eukaryotes, DNA
2698-541: A role in the synthesis and packaging of proteins, respectively. Biomolecules such as proteins can be engulfed by lysosomes , another specialized organelle. Plant cells have additional organelles that distinguish them from animal cells such as a cell wall that provides support for the plant cell, chloroplasts that harvest sunlight energy to produce sugar, and vacuoles that provide storage and structural support as well as being involved in reproduction and breakdown of plant seeds. Eukaryotic cells also have cytoskeleton that
2840-436: A separate clade as some protists may be more closely related to plants, fungi, or animals than they are to other protists. Like groupings such as algae , invertebrates , or protozoans , the protist grouping is not a formal taxonomic group but is used for convenience. Most protists are unicellular; these are called microbial eukaryotes. Plants are mainly multicellular organisms , predominantly photosynthetic eukaryotes of
2982-851: A serious health issue. Substances known to be potentially dangerous include aconite , secretions from the Asiatic toad , powdered centipede, the Chinese beetle ( Mylabris phalerata , Ban mao), and certain fungi. There are health problems associated with Aristolochia . Toxic effects are also frequent with Aconitum . To avoid its toxic adverse effects Xanthium sibiricum must be processed. Hepatotoxicity has been reported with products containing Reynoutria multiflora ( synonym Polygonum multiflorum ), glycyrrhizin , Senecio and Symphytum . The evidence suggests that hepatotoxic herbs also include Dictamnus dasycarpus , Astragalus membranaceus , and Paeonia lactiflora ; although there
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#17327717706473124-461: A similar effect at preventing and treating influenza as antiviral medication. Due to the poor quality of these medical studies, there is insufficient evidence to support or dismiss the use of Chinese medicinal herbs for the treatment of influenza. There is a need for larger and higher quality randomized clinical trials to determine how effective Chinese herbal medicine is for treating people with influenza. A 2005 Cochrane review found that although
3266-423: A single carbon atom can form four single covalent bonds such as in methane , two double covalent bonds such as in carbon dioxide (CO 2 ), or a triple covalent bond such as in carbon monoxide (CO). Moreover, carbon can form very long chains of interconnecting carbon–carbon bonds such as octane or ring-like structures such as glucose . The simplest form of an organic molecule is the hydrocarbon , which
3408-501: A sort of permanent catheter , which is more profitable than killing the bears. More than 12,000 asiatic black bears are held in "bear farms", where they suffer cruel conditions while being held in tiny cages. The catheter leads through a permanent hole in the abdomen directly to the gall bladder , which can cause severe pain. Increased international attention has mostly stopped the use of bile outside of China; gallbladders from butchered cattle ( 牛胆 ; 牛膽 ; niú dǎn ) are recommended as
3550-446: A specific enzyme. Enzymes are crucial to metabolism because they allow organisms to drive desirable reactions that require energy that will not occur by themselves, by coupling them to spontaneous reactions that release energy. Enzymes act as catalysts —they allow a reaction to proceed more rapidly without being consumed by it—by reducing the amount of activation energy needed to convert reactants into products . Enzymes also allow
3692-649: A substitute for this ingredient. Collecting American ginseng to assist the Asian traditional medicine trade has made ginseng the most harvested wild plant in North America for the last two centuries, which eventually led to a listing on CITES Appendix II . Chinese medicinal plant materials (CMPMs) release chemicals that attracts the Drugstore beetle , leading to the accumulation of this pest and further infestation and damage to these plants. Chinese herbology
3834-399: A unified theory as the modern synthesis reconciled Darwinian evolution with classical genetics . In the 1940s and early 1950s, a series of experiments by Alfred Hershey and Martha Chase pointed to DNA as the component of chromosomes that held the trait-carrying units that had become known as genes . A focus on new kinds of model organisms such as viruses and bacteria, along with
3976-421: A varied mix of traits, and reproduction is able to increase any population, Darwin argued that in the natural world, it was nature that played the role of humans in selecting for specific traits. Darwin inferred that individuals who possessed heritable traits better adapted to their environments are more likely to survive and produce more offspring than other individuals. He further inferred that this would lead to
4118-492: A water molecule again. In pure water , the number of hydrogen ions balances (or equals) the number of hydroxyl ions, resulting in a pH that is neutral. Organic compounds are molecules that contain carbon bonded to another element such as hydrogen. With the exception of water, nearly all the molecules that make up each organism contain carbon. Carbon can form covalent bonds with up to four other atoms, enabling it to form diverse, large, and complex molecules. For example,
4260-536: Is evolution , which explains the unity and diversity of life. Energy processing is also important to life as it allows organisms to move , grow, and reproduce . Finally, all organisms are able to regulate their own internal environments . Biologists are able to study life at multiple levels of organization , from the molecular biology of a cell to the anatomy and physiology of plants and animals, and evolution of populations. Hence, there are multiple subdisciplines within biology , each defined by
4402-419: Is 'sweet herb,' an adequate description for the licorice root. Ku means 'bitter', thus Ku Shen ( Sophorae flavescentis ) translates as 'bitter herb.' The locations or provinces in which herbs are grown often figure into herb names. For example, Bei Sha Shen ( Radix glehniae ) is grown and harvested in northern China, whereas Nan Sha Shen ( Radix adenophorae ) originated in southern China. And
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4544-444: Is a central feature of sexual reproduction in eukaryotes, and the most fundamental function of meiosis appears to be conservation of the integrity of the genome that is passed on to progeny by parents. Two aspects of sexual reproduction , meiotic recombination and outcrossing , are likely maintained respectively by the adaptive advantages of recombinational repair of genomic DNA damage and genetic complementation which masks
4686-641: Is a large family of organic compounds that are composed of hydrogen atoms bonded to a chain of carbon atoms. A hydrocarbon backbone can be substituted by other elements such as oxygen (O), hydrogen (H), phosphorus (P), and sulfur (S), which can change the chemical behavior of that compound. Groups of atoms that contain these elements (O-, H-, P-, and S-) and are bonded to a central carbon atom or skeleton are called functional groups . There are six prominent functional groups that can be found in organisms: amino group , carboxyl group , carbonyl group , hydroxyl group , phosphate group , and sulfhydryl group . In 1953,
4828-462: Is a pseudoscientific practice with potentially unreliable product quality, safety hazards or misleading health advice. There are regulatory bodies, such as China GMP (Good Manufacturing Process) of herbal products. However, there have been notable cases of an absence of quality control during herbal product preparation. There is a lack of high-quality scientific research on herbology practices and product effectiveness for anti-disease activity. In
4970-480: Is a small polar molecule with a bent shape formed by the polar covalent bonds of two hydrogen (H) atoms to one oxygen (O) atom (H 2 O). Because the O–H bonds are polar, the oxygen atom has a slight negative charge and the two hydrogen atoms have a slight positive charge. This polar property of water allows it to attract other water molecules via hydrogen bonds, which makes water cohesive . Surface tension results from
5112-918: Is a term of convenience as not all algae are closely related. Algae comprise several distinct clades such as glaucophytes , which are microscopic freshwater algae that may have resembled in form to the early unicellular ancestor of Plantae. Unlike glaucophytes, the other algal clades such as red and green algae are multicellular. Green algae comprise three major clades: chlorophytes , coleochaetophytes , and stoneworts . Fungi are eukaryotes that digest foods outside their bodies, secreting digestive enzymes that break down large food molecules before absorbing them through their cell membranes. Many fungi are also saprobes , feeding on dead organic matter, making them important decomposers in ecological systems. Animals are multicellular eukaryotes. With few exceptions, animals consume organic material , breathe oxygen , are able to move , can reproduce sexually , and grow from
5254-403: Is catalyzed by lactate dehydrogenase in a reversible reaction. Lactate can also be used as an indirect precursor for liver glycogen. During recovery, when oxygen becomes available, NAD attaches to hydrogen from lactate to form ATP. In yeast, the waste products are ethanol and carbon dioxide. This type of fermentation is known as alcoholic or ethanol fermentation . The ATP generated in this process
5396-465: Is considered as the oldest book on Chinese herbal medicine. It classifies 365 species of roots, grass, woods, furs, animals and stones into three categories of herbal medicine: The original text of Shennong's Materia Medica has been lost; however, there are extant translations. The true date of origin is believed to fall into the late Western Han dynasty (i.e., the first century BCE). The Treatise on Cold Damage Disorders and Miscellaneous Illnesses
5538-457: Is interpreted as stating that these three rulers are not the three classes of Shénnóng mentioned previously. This chapter in particular outlines a more forceful approach. Later on Zhang Zihe ( a.k.a. Zhang Cong-zhen, 1156–1228) is credited with founding the 'Attacking School' which criticized the overuse of tonics. Arguably the most important of these later works is the Compendium of Materia Medica ( Bencao Gangmu , 本草綱目 ) compiled during
5680-441: Is made by substrate-level phosphorylation , which does not require oxygen. Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organism's metabolic activities via cellular respiration. This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water. In most cases, oxygen
5822-535: Is made up of microtubules , intermediate filaments , and microfilaments , all of which provide support for the cell and are involved in the movement of the cell and its organelles. In terms of their structural composition, the microtubules are made up of tubulin (e.g., α-tubulin and β-tubulin ) whereas intermediate filaments are made up of fibrous proteins. Microfilaments are made up of actin molecules that interact with other strands of proteins. All cells require energy to sustain cellular processes. Metabolism
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5964-526: Is mainly in the cell nucleus . In prokaryotes, the DNA is held within the nucleoid . The genetic information is held within genes, and the complete assemblage in an organism is called its genotype . DNA replication is a semiconservative process whereby each strand serves as a template for a new strand of DNA. Mutations are heritable changes in DNA. They can arise spontaneously as a result of replication errors that were not corrected by proofreading or can be induced by an environmental mutagen such as
6106-522: Is misleading in the sense that, while plant elements are by far the most commonly used substances, animal, human, and mineral products are also used, some of which are poisonous. In the Huangdi Neijing they are referred to as 毒藥 (pinyin: dúyào ) which means toxin, poison, or medicine. Paul U. Unschuld points out that this is similar etymology to the Greek pharmakon and so he uses
6248-419: Is mixed in to form a herbal dough. This dough is then machine cut into tiny pieces, a small amount of excipients are added for a smooth and consistent exterior, and they are spun into pills. These medicines are not patented in the traditional sense of the word. No one has exclusive rights to the formula. Instead, "patent" refers to the standardization of the formula. In China, all Chinese patent medicines of
6390-519: Is no evidence that they cause liver damage. Contrary to popular belief, Ganoderma lucidum mushroom extract, as an adjuvant for cancer immunotherapy, appears to have the potential for toxicity. Also, adulteration of some herbal medicine preparations with conventional drugs which may cause serious adverse effects, such as corticosteroids , phenylbutazone , phenytoin , and glibenclamide , has been reported. However, many adverse reactions are due to misuse or abuse of Chinese medicine. For example,
6532-493: Is not enough robust evidence to support the effectiveness of traditional Chinese medicine herbs to stop the bleeding from haemorrhoids . A 2008 Cochrane review found promising evidence for the use of Chinese herbal medicine in relieving painful menstruation , compared to conventional medicine such as NSAIDs and the oral contraceptive pill, but the findings are of low methodological quality. A 2012 Cochrane review found weak evidence suggesting that some Chinese medicinal herbs have
6674-399: Is one of the key ways a cell releases chemical energy to fuel cellular activity. The overall reaction occurs in a series of biochemical steps, some of which are redox reactions. Although cellular respiration is technically a combustion reaction , it clearly does not resemble one when it occurs in a cell because of the slow, controlled release of energy from the series of reactions. Sugar in
6816-407: Is pulled to the separate poles of the bacterium as it increases the size to prepare for splitting. Growth of a new cell wall begins to separate the bacterium (triggered by FtsZ polymerization and "Z-ring" formation). The new cell wall ( septum ) fully develops, resulting in the complete split of the bacterium. The new daughter cells have tightly coiled DNA rods, ribosomes , and plasmids . Meiosis
6958-399: Is released as a waste product. Most plants, algae , and cyanobacteria perform photosynthesis, which is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the energy necessary for life on Earth. Photosynthesis has four stages: Light absorption , electron transport, ATP synthesis, and carbon fixation . Light absorption is
7100-412: Is represented as a fork or split on the phylogenetic tree. Phylogenetic trees are the basis for comparing and grouping different species. Different species that share a feature inherited from a common ancestor are described as having homologous features (or synapomorphy ). Phylogeny provides the basis of biological classification. This classification system is rank-based, with the highest rank being
7242-468: Is the process by which genes and traits are passed on from parents to offspring. It has several principles. The first is that genetic characteristics, alleles , are discrete and have alternate forms (e.g., purple vs. white or tall vs. dwarf), each inherited from one of two parents. Based on the law of dominance and uniformity , which states that some alleles are dominant while others are recessive ; an organism with at least one dominant allele will display
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#17327717706477384-485: Is the set of chemical reactions in an organism. The three main purposes of metabolism are: the conversion of food to energy to run cellular processes; the conversion of food/fuel to monomer building blocks; and the elimination of metabolic wastes . These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolic reactions may be categorized as catabolic —the breaking down of compounds (for example,
7526-410: Is the study of chemical processes within and relating to living organisms . Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including molecular synthesis, modification, mechanisms, and interactions. Life arose from the Earth's first ocean, which formed some 3.8 billion years ago. Since then, water continues to be
7668-493: Is to store, transmit, and express hereditary information. Cell theory states that cells are the fundamental units of life, that all living things are composed of one or more cells, and that all cells arise from preexisting cells through cell division . Most cells are very small, with diameters ranging from 1 to 100 micrometers and are therefore only visible under a light or electron microscope . There are generally two types of cells: eukaryotic cells, which contain
7810-509: Is written in almost 2 million Chinese characters , classified into 16 divisions and 60 orders. For every herb there are entries on their names, a detailed description of their appearance and odor, nature, medical function, side effects, recipes, etc. The text contains information that was proven to be wrong due to Li's limited scientific and technical knowledge. For example, it is claimed that quicksilver (mercury) and lead were not toxic . Li also claimed that otters are always male and that
7952-750: The Treatise on Cold Damage Disorders and the Essential Prescriptions of the Golden Casket , which were edited separately in the eleventh century, under the Song dynasty . Succeeding generations augmented these works, as in the Yaoxing Lun ( 藥性論 ; 药性论 ; 'Treatise on the Nature of Medicinal Herbs'), a 7th-century Tang dynasty Chinese treatise on herbal medicine. There
8094-644: The Cambrian explosion . During the Permian period, synapsids , including the ancestors of mammals , dominated the land, but most of this group became extinct in the Permian–Triassic extinction event 252 million years ago. During the recovery from this catastrophe, archosaurs became the most abundant land vertebrates; one archosaur group, the dinosaurs, dominated the Jurassic and Cretaceous periods. After
8236-495: The Cretaceous–Paleogene extinction event 66 million years ago killed off the non-avian dinosaurs, mammals increased rapidly in size and diversity . Such mass extinctions may have accelerated evolution by providing opportunities for new groups of organisms to diversify. Bacteria are a type of cell that constitute a large domain of prokaryotic microorganisms . Typically a few micrometers in length, bacteria have
8378-535: The Miller–Urey experiment showed that organic compounds could be synthesized abiotically within a closed system mimicking the conditions of early Earth , thus suggesting that complex organic molecules could have arisen spontaneously in early Earth (see abiogenesis ). Macromolecules are large molecules made up of smaller subunits or monomers . Monomers include sugars, amino acids, and nucleotides. Carbohydrates include monomers and polymers of sugars. Lipids are
8520-678: The Ming dynasty by Li Shizhen , which is still used today for consultation and reference. The use of Chinese herbs was popular during the medieval age in western Asian and Islamic countries. They were traded through the Silk Road from the East to the West. Cinnamon , ginger , rhubarb , nutmeg and cubeb are mentioned as Chinese herbs by medieval Islamic medical scholars Such as Rhazes (854–925 CE), Haly Abbas (930–994 CE) and Avicenna (980–1037 CE). There were also multiple similarities between
8662-492: The Precambrian about 1.5 billion years ago and can be classified into eight major clades : alveolates , excavates , stramenopiles , plants, rhizarians , amoebozoans , fungi , and animals. Five of these clades are collectively known as protists , which are mostly microscopic eukaryotic organisms that are not plants, fungi, or animals. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor ), protists by themselves do not constitute
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#17327717706478804-727: The activator is the transcription factor that stimulates transcription when it binds to the sequence near or at the promoter. Negative regulation occurs when another transcription factor called a repressor binds to a DNA sequence called an operator , which is part of an operon, to prevent transcription. Repressors can be inhibited by compounds called inducers (e.g., allolactose ), thereby allowing transcription to occur. Specific genes that can be activated by inducers are called inducible genes , in contrast to constitutive genes that are almost constantly active. In contrast to both, structural genes encode proteins that are not involved in gene regulation. In addition to regulatory events involving
8946-592: The bacterial phyla have species that can be grown in the laboratory. Archaea constitute the other domain of prokaryotic cells and were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom ), a term that has fallen out of use. Archaeal cells have unique properties separating them from the other two domains , Bacteria and Eukaryota . Archaea are further divided into multiple recognized phyla . Archaea and bacteria are generally similar in size and shape, although
9088-530: The black market with such substances, and the black market in rhinoceros horn, for example, has reduced the world's rhino population by more than 90 percent over the past 40 years. Concerns have also arisen over the use of turtle plastron and seahorses . TCM recognizes bear bile as a medicinal. In 1988, the Chinese Ministry of Health started controlling bile production, which previously used bears killed before winter. Now bears are fitted with
9230-404: The cell . In 1838, Schleiden and Schwann began promoting the now universal ideas that (1) the basic unit of organisms is the cell and (2) that individual cells have all the characteristics of life, although they opposed the idea that (3) all cells come from the division of other cells, continuing to support spontaneous generation . However, Robert Remak and Rudolf Virchow were able to reify
9372-403: The cell membrane of another cell or located deep inside a cell. There are generally four types of chemical signals: autocrine , paracrine , juxtacrine , and hormones . In autocrine signaling, the ligand affects the same cell that releases it. Tumor cells, for example, can reproduce uncontrollably because they release signals that initiate their own self-division. In paracrine signaling,
9514-416: The circulatory systems of animals or vascular systems of plants to reach their target cells. Once a ligand binds with a receptor, it can influence the behavior of another cell, depending on the type of receptor. For instance, neurotransmitters that bind with an inotropic receptor can alter the excitability of a target cell. Other types of receptors include protein kinase receptors (e.g., receptor for
9656-528: The domain followed by kingdom , phylum , class , order , family , genus , and species . All organisms can be classified as belonging to one of three domains : Archaea (originally Archaebacteria), bacteria (originally eubacteria), or eukarya (includes the fungi, plant, and animal kingdoms). The history of life on Earth traces how organisms have evolved from the earliest emergence of life to present day. Earth formed about 4.5 billion years ago and all life on Earth, both living and extinct, descended from
9798-481: The duplication of its DNA and some of its organelles , and the subsequent partitioning of its cytoplasm into two daughter cells in a process called cell division . In eukaryotes (i.e., animal, plant, fungal , and protist cells), there are two distinct types of cell division: mitosis and meiosis . Mitosis is part of the cell cycle, in which replicated chromosomes are separated into two new nuclei. Cell division gives rise to genetically identical cells in which
9940-403: The kingdom Plantae, which would exclude fungi and some algae . Plant cells were derived by endosymbiosis of a cyanobacterium into an early eukaryote about one billion years ago, which gave rise to chloroplasts. The first several clades that emerged following primary endosymbiosis were aquatic and most of the aquatic photosynthetic eukaryotic organisms are collectively described as algae, which
10082-423: The microscope . It was then that scholars discovered spermatozoa , bacteria, infusoria and the diversity of microscopic life. Investigations by Jan Swammerdam led to new interest in entomology and helped to develop techniques of microscopic dissection and staining . Advances in microscopy had a profound impact on biological thinking. In the early 19th century, biologists pointed to the central importance of
10224-412: The mitochondrial cristae . Oxidative phosphorylation comprises the electron transport chain, which is a series of four protein complexes that transfer electrons from one complex to another, thereby releasing energy from NADH and FADH 2 that is coupled to the pumping of protons (hydrogen ions) across the inner mitochondrial membrane ( chemiosmosis ), which generates a proton motive force . Energy from
10366-546: The phenotype of that dominant allele. During gamete formation, the alleles for each gene segregate, so that each gamete carries only one allele for each gene. Heterozygotic individuals produce gametes with an equal frequency of two alleles. Finally, the law of independent assortment , states that genes of different traits can segregate independently during the formation of gametes, i.e., genes are unlinked. An exception to this rule would include traits that are sex-linked . Test crosses can be performed to experimentally determine
10508-497: The regulation of the rate of a metabolic reaction, for example in response to changes in the cell's environment or to signals from other cells. Cellular respiration is a set of metabolic reactions and processes that take place in cells to convert chemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. The reactions involved in respiration are catabolic reactions , which break large molecules into smaller ones, releasing energy. Respiration
10650-504: The Chinese words for north and south are respectively bei and nan . Chuan Bei Mu ( Bulbus fritillariae cirrhosae ) and Chuan Niu Xi ( Radix cyathulae ) are both found in Sichuan province, as the character chuan indicates in their names. Some herbs, like Fang Feng ( Radix Saposhnikoviae ), literally 'prevent wind,' preventing or treating wind-related illnesses. Xu Duan ( Radix Dipsaci ), literally 'restore
10792-599: The Moupin langur is ten-foot (three-metre) tall, has backwards feet and can be caught when it draws its upper lip over its eyes. The British historian Joseph Needham writes about the Compendium in his Science and Civilisation in China . The text provided classification of how traditional medicine was compiled and formatted, as well as biology classification of both plants and animals. The text corrected some mistakes in
10934-481: The Phanerozoic eon that began 539 million years ago being subdivided into Paleozoic , Mesozoic , and Cenozoic eras. These three eras together comprise eleven periods ( Cambrian , Ordovician , Silurian , Devonian , Carboniferous , Permian , Triassic , Jurassic , Cretaceous , Tertiary , and Quaternary ). The similarities among all known present-day species indicate that they have diverged through
11076-696: The accumulation of favorable traits over successive generations, thereby increasing the match between the organisms and their environment. A species is a group of organisms that mate with one another and speciation is the process by which one lineage splits into two lineages as a result of having evolved independently from each other. For speciation to occur, there has to be reproductive isolation . Reproductive isolation can result from incompatibilities between genes as described by Bateson–Dobzhansky–Muller model . Reproductive isolation also tends to increase with genetic divergence . Speciation can occur when there are physical barriers that divide an ancestral species,
11218-589: The body plan and the number, identity, and pattern of body parts. Among the most important toolkit genes are the Hox genes . Hox genes determine where repeating parts, such as the many vertebrae of snakes, will grow in a developing embryo or larva. Evolution is a central organizing concept in biology. It is the change in heritable characteristics of populations over successive generations . In artificial selection , animals were selectively bred for specific traits. Given that traits are inherited, populations contain
11360-461: The bowels, and eliminates dampness". These categories mainly include: Many herbs earn their names from their unique physical appearance. Examples of such names include Niu Xi ( Radix cyathulae seu achyranthis ), 'cow's knees,' which has big joints that might look like cow knees; Bai Mu Er ( Fructificatio tremellae fuciformis ), 'white wood ear', which is white and resembles an ear; Gou Ji ( Rhizoma cibotii ), 'dog spine,' which resembles
11502-450: The breaking down of glucose to pyruvate by cellular respiration ); or anabolic —the building up ( synthesis ) of compounds (such as proteins, carbohydrates, lipids, and nucleic acids). Usually, catabolism releases energy, and anabolism consumes energy. The chemical reactions of metabolism are organized into metabolic pathways , in which one chemical is transformed through a series of steps into another chemical, each step being facilitated by
11644-410: The broken,' treating torn soft tissues and broken bones. Many herbs indigenous to other countries have been incorporated into the Chinese materia medica. Xi Yang Shen ( Radix panacis quinquefolii ), imported from North American crops, translates as 'western ginseng,' while Dong Yang Shen ( Radix ginseng Japonica ), grown in and imported from North Asian countries, is 'eastern ginseng.' From
11786-506: The clinical uses of these herbs in Chinese and Islamic medicine. There are roughly 13,000 medicinals used in China and over 100,000 medicinal recipes recorded in the ancient literature. Plant elements and extracts are by far the most common elements used. In the classic Handbook of Traditional Drugs from 1941, 517 drugs were listed – out of these, only 45 were animal parts, and 30 were minerals. For many plants used as medicinals, detailed instructions have been handed down not only regarding
11928-410: The cohesive force due to the attraction between molecules at the surface of the liquid. Water is also adhesive as it is able to adhere to the surface of any polar or charged non-water molecules. Water is denser as a liquid than it is as a solid (or ice). This unique property of water allows ice to float above liquid water such as ponds, lakes, and oceans, thereby insulating the liquid below from
12070-433: The cold air above. Water has the capacity to absorb energy, giving it a higher specific heat capacity than other solvents such as ethanol . Thus, a large amount of energy is needed to break the hydrogen bonds between water molecules to convert liquid water into water vapor . As a molecule, water is not completely stable as each water molecule continuously dissociates into hydrogen and hydroxyl ions before reforming into
12212-418: The copious historical bencao literature. He modelled his work on a Song dynasty compilation, especially its use of non-medical texts. He worked for more than three decades, with the help of his son, Li Jianyuan, who drew the illustrations. He finished a draft of the text in 1578, the printer began to carve the blocks in 1593, but it was not published until 1596, three years after Li died. Li Jianyuan presented
12354-501: The cytoplasm of a cell, there are many biomolecules such as proteins and nucleic acids . In addition to biomolecules, eukaryotic cells have specialized structures called organelles that have their own lipid bilayers or are spatially units. These organelles include the cell nucleus , which contains most of the cell's DNA, or mitochondria , which generate adenosine triphosphate (ATP) to power cellular processes. Other organelles such as endoplasmic reticulum and Golgi apparatus play
12496-455: The cytoplasm, where it is converted to waste products that may be removed from the cell. This serves the purpose of oxidizing the electron carriers so that they can perform glycolysis again and removing the excess pyruvate. Fermentation oxidizes NADH to NAD so it can be re-used in glycolysis. In the absence of oxygen, fermentation prevents the buildup of NADH in the cytoplasm and provides NAD for glycolysis. This waste product varies depending on
12638-625: The development of biological knowledge. He explored biological causation and the diversity of life. His successor, Theophrastus , began the scientific study of plants. Scholars of the medieval Islamic world who wrote on biology included al-Jahiz (781–869), Al-Dīnawarī (828–896), who wrote on botany, and Rhazes (865–925) who wrote on anatomy and physiology . Medicine was especially well studied by Islamic scholars working in Greek philosopher traditions, while natural history drew heavily on Aristotelian thought. Biology began to quickly develop with Anton van Leeuwenhoek 's dramatic improvement of
12780-418: The development of body form, is the result of spatial differences in gene expression. A small fraction of the genes in an organism's genome called the developmental-genetic toolkit control the development of that organism. These toolkit genes are highly conserved among phyla , meaning that they are ancient and very similar in widely separated groups of animals. Differences in deployment of toolkit genes affect
12922-440: The developmental fate of a cell, which becomes more restrictive during development. Differentiation is the process by which specialized cells arise from less specialized cells such as stem cells . Stem cells are undifferentiated or partially differentiated cells that can differentiate into various types of cells and proliferate indefinitely to produce more of the same stem cell. Cellular differentiation dramatically changes
13064-411: The discovery of archaea in almost every habitat , including soil, oceans, and marshlands . Archaea are particularly numerous in the oceans, and the archaea in plankton may be one of the most abundant groups of organisms on the planet. Archaea are a major part of Earth's life . They are part of the microbiota of all organisms. In the human microbiome , they are important in the gut , mouth, and on
13206-420: The discovery of the double-helical structure of DNA by James Watson and Francis Crick in 1953, marked the transition to the era of molecular genetics . From the 1950s onwards, biology has been vastly extended in the molecular domain. The genetic code was cracked by Har Gobind Khorana , Robert W. Holley and Marshall Warren Nirenberg after DNA was understood to contain codons . The Human Genome Project
13348-634: The earliest terrestrial ecosystems , at least 2.7 billion years ago. Microorganisms are thought to have paved the way for the inception of land plants in the Ordovician period. Land plants were so successful that they are thought to have contributed to the Late Devonian extinction event . Ediacara biota appear during the Ediacaran period, while vertebrates , along with most other modern phyla originated about 525 million years ago during
13490-623: The earliest literature are lists of prescriptions for specific ailments, exemplified by the manuscript Recipes for 52 Ailments , found in the Mawangdui which were sealed in 168 BCE. The first traditionally recognized herbalist is Shénnóng ( 神農 , lit. ' Divine Farmer ' ), a mythical god-like figure, who is said to have lived around 2800 BCE. He allegedly tasted hundreds of herbs and imparted his knowledge of medicinal and poisonous plants to farmers. His Shénnóng Běn Cǎo Jīng ( 神農本草經 , Shennong's Materia Medica )
13632-865: The earliest records regarding the use of medicinals to today, the toxicity of certain substances has been described in all Chinese materia medica. Since TCM has become more popular in the Western world, there are increasing concerns about the potential toxicity of many traditional Chinese medicinals including plants, animal parts and minerals. For most medicinals, efficacy and toxicity testing are based on traditional knowledge rather than laboratory analysis. The toxicity in some cases could be confirmed by modern research (i.e., in scorpion ); in some cases it could not (i.e., in Curculigo ). Further, ingredients may have different names in different locales or in historical texts, and different preparations may have similar names for
13774-458: The evidence was weak for the use of any single herb, there was low quality evidence that some Chinese medicinal herbs may be effective for the treatment of acute pancreatitis . Successful results have been scarce: artemisinin is one of few examples, as effective treatment for malaria derived from Artemisia annua , which is traditionally used to treat fever. Chinese herbology is largely pseudoscience , with no valid mechanism of action for
13916-481: The expression of deleterious recessive mutations . The beneficial effect of genetic complementation, derived from outcrossing (cross-fertilization) is also referred to as hybrid vigor or heterosis. Charles Darwin in his 1878 book The Effects of Cross and Self-Fertilization in the Vegetable Kingdom at the start of chapter XII noted “The first and most important of the conclusions which may be drawn from
14058-455: The form of glucose is the main nutrient used by animal and plant cells in respiration. Cellular respiration involving oxygen is called aerobic respiration, which has four stages: glycolysis , citric acid cycle (or Krebs cycle), electron transport chain , and oxidative phosphorylation . Glycolysis is a metabolic process that occurs in the cytoplasm whereby glucose is converted into two pyruvates , with two net molecules of ATP being produced at
14200-1009: The herbal sources listed below, there is little or no evidence for efficacy or proof of safety across consumer age groups and disease conditions for which they are intended. There are over 300 herbs in common use. Some of the most commonly used herbs are Ginseng ( 人参 ; 人參 ; rénshēn ), wolfberry ( 枸杞子 ; gǒuqǐzǐ), dong quai ( Angelica sinensis , 当归 ; 當歸 ; dāngguī ), astragalus ( 黄耆 ; 黃耆 ; huángqí ), atractylodes ( 白术 ; 白朮 ; báizhú ), bupleurum ( 柴胡 ; cháihú ), cinnamon (cinnamon twigs ( 桂枝 ; guìzhī ) and cinnamon bark ( 肉桂 ; ròuguì )), coptis ( 黄连 ; 黃連 ; huánglián ), ginger ( 姜 ; 薑 ; jiāng ), hoelen ( 茯苓 ; fúlíng ), licorice ( 甘草 ; gāncǎo ), ephedra sinica ( 麻黄 ; 麻黃 ; máhuáng ), peony (white: 白芍 ; báisháo and reddish: 赤芍 ; chìsháo ), rehmannia ( 地黄 ; 地黃 ; dìhuáng ), rhubarb ( 大黄 ; 大黃 ; dàhuáng ), and salvia ( 丹参 ; 丹參 ; dānshēn ). In Chinese herbology, there are 50 "fundamental" herbs, as given in
14342-426: The hormone insulin ) and G protein-coupled receptors . Activation of G protein-coupled receptors can initiate second messenger cascades. The process by which a chemical or physical signal is transmitted through a cell as a series of molecular events is called signal transduction . The cell cycle is a series of events that take place in a cell that cause it to divide into two daughter cells. These events include
14484-414: The initial step of photosynthesis whereby light energy is absorbed by chlorophyll pigments attached to proteins in the thylakoid membranes . The absorbed light energy is used to remove electrons from a donor (water) to a primary electron acceptor, a quinone designated as Q. In the second stage, electrons move from the quinone primary electron acceptor through a series of electron carriers until they reach
14626-403: The knowledge of herbs and diseases at the time. Several new herbs and more details from experiments were also included. It also has notes and records on general medical data and medical history. The text includes information on pharmaceutics, biology , chemistry , geography , mineralogy , geology , history , and even mining and astronomy . Chinese herbology The term herbology
14768-406: The last eukaryotic common ancestor. Prokaryotes (i.e., archaea and bacteria) can also undergo cell division (or binary fission ). Unlike the processes of mitosis and meiosis in eukaryotes, binary fission in prokaryotes takes place without the formation of a spindle apparatus on the cell. Before binary fission, DNA in the bacterium is tightly coiled. After it has uncoiled and duplicated, it
14910-405: The ligand diffuses to nearby cells and affects them. For example, brain cells called neurons release ligands called neurotransmitters that diffuse across a synaptic cleft to bind with a receptor on an adjacent cell such as another neuron or muscle cell . In juxtacrine signaling, there is direct contact between the signaling and responding cells. Finally, hormones are ligands that travel through
15052-431: The locations and areas where they grow best, but also regarding the best timing of planting and harvesting them. Some animal parts used as medicinals can be considered rather strange such as cows' gallstones. Furthermore, the classic materia medica Bencao Gangmu describes the use of 35 traditional Chinese medicines derived from the human body , including bones, fingernail, hairs, dandruff, earwax, impurities on
15194-467: The majority of its treatments. The traditional practice of using now- endangered species is controversial within TCM. Modern Materia Medicas such as Bensky, Clavey and Stoger's comprehensive Chinese herbal text discuss substances derived from endangered species in an appendix, emphasizing alternatives. Parts of endangered species used as TCM drugs include tiger bones and rhinoceros horn . Poachers supply
15336-444: The membrane serving as membrane transporters , and peripheral proteins that loosely attach to the outer side of the cell membrane, acting as enzymes shaping the cell. Cell membranes are involved in various cellular processes such as cell adhesion , storing electrical energy , and cell signalling and serve as the attachment surface for several extracellular structures such as a cell wall , glycocalyx , and cytoskeleton . Within
15478-681: The misuse of the dietary supplement Ephedra (containing ephedrine ) can lead to adverse events including gastrointestinal problems as well as sudden death from cardiomyopathy . Products adulterated with pharmaceuticals for weight loss or erectile dysfunction are one of the main concerns. Chinese herbal medicine has been a major cause of acute liver failure in China. Most Chinese herbs are safe but some have shown not to be. Reports have shown products being contaminated with drugs, toxins, or false reporting of ingredients. Some herbs used in TCM may also react with drugs, have side effects, or be dangerous to people with certain medical conditions. Only
15620-403: The mitotic phase of an animal cell cycle—the division of the mother cell into two genetically identical daughter cells. The cell cycle is a vital process by which a single-celled fertilized egg develops into a mature organism, as well as the process by which hair, skin, blood cells , and some internal organs are renewed. After cell division, each of the daughter cells begin the interphase of
15762-437: The most abundant molecule in every organism. Water is important to life because it is an effective solvent , capable of dissolving solutes such as sodium and chloride ions or other small molecules to form an aqueous solution . Once dissolved in water, these solutes are more likely to come in contact with one another and therefore take part in chemical reactions that sustain life. In terms of its molecular structure , water
15904-403: The nature of their research questions and the tools that they use. Like other scientists, biologists use the scientific method to make observations , pose questions, generate hypotheses , perform experiments, and form conclusions about the world around them. Life on Earth, which emerged more than 3.7 billion years ago, is immensely diverse. Biologists have sought to study and classify
16046-441: The observations given in this volume, is that generally cross-fertilisation is beneficial and self-fertilisation often injurious, at least with the plants on which I experimented.” Genetic variation , often produced as a byproduct of sexual reproduction, may provide long-term advantages to those sexual lineages that engage in outcrossing . Genetics is the scientific study of inheritance. Mendelian inheritance , specifically,
16188-517: The only class of macromolecules that are not made up of polymers. They include steroids , phospholipids , and fats, largely nonpolar and hydrophobic (water-repelling) substances. Proteins are the most diverse of the macromolecules. They include enzymes , transport proteins , large signaling molecules, antibodies , and structural proteins . The basic unit (or monomer) of a protein is an amino acid . Twenty amino acids are used in proteins. Nucleic acids are polymers of nucleotides . Their function
16330-404: The organism. In skeletal muscles, the waste product is lactic acid . This type of fermentation is called lactic acid fermentation . In strenuous exercise, when energy demands exceed energy supply, the respiratory chain cannot process all of the hydrogen atoms joined by NADH. During anaerobic glycolysis, NAD regenerates when pairs of hydrogen combine with pyruvate to form lactate. Lactate formation
16472-428: The possibility of common descent . Serious evolutionary thinking originated with the works of Jean-Baptiste Lamarck , who presented a coherent theory of evolution. The British naturalist Charles Darwin , combining the biogeographical approach of Humboldt , the uniformitarian geology of Lyell , Malthus's writings on population growth, and his own morphological expertise and extensive natural observations, forged
16614-907: The process of evolution from their common ancestor. Biologists regard the ubiquity of the genetic code as evidence of universal common descent for all bacteria , archaea , and eukaryotes . Microbial mats of coexisting bacteria and archaea were the dominant form of life in the early Archean eon and many of the major steps in early evolution are thought to have taken place in this environment. The earliest evidence of eukaryotes dates from 1.85 billion years ago, and while they may have been present earlier, their diversification accelerated when they started using oxygen in their metabolism . Later, around 1.7 billion years ago, multicellular organisms began to appear, with differentiated cells performing specialised functions. Algae-like multicellular land plants are dated back to about 1 billion years ago, although evidence suggests that microorganisms formed
16756-539: The process such as transcription , RNA splicing , translation , and post-translational modification of a protein. Gene expression can be influenced by positive or negative regulation, depending on which of the two types of regulatory proteins called transcription factors bind to the DNA sequence close to or at a promoter. A cluster of genes that share the same promoter is called an operon , found mainly in prokaryotes and some lower eukaryotes (e.g., Caenorhabditis elegans ). In positive regulation of gene expression,
16898-517: The promoter, gene expression can also be regulated by epigenetic changes to chromatin , which is a complex of DNA and protein found in eukaryotic cells. Development is the process by which a multicellular organism (plant or animal) goes through a series of changes, starting from a single cell, and taking on various forms that are characteristic of its life cycle. There are four key processes that underlie development: Determination , differentiation , morphogenesis , and growth. Determination sets
17040-406: The proton motive force drives the enzyme ATP synthase to synthesize more ATPs by phosphorylating ADPs . The transfer of electrons terminates with molecular oxygen being the final electron acceptor . If oxygen were not present, pyruvate would not be metabolized by cellular respiration but undergoes a process of fermentation . The pyruvate is not transported into the mitochondrion but remains in
17182-628: The reference text, although these herbs are not universally recognized as such in other texts. The herbs are: In addition to the above, many other Chinese herbs and other substances are in common use, and these include: Traditional Chinese herbs are used either standalone, or in a grouping, jointly with other herbs. When several herbs are used together, this amalgamation is called a 'herbal formula'. There are, generally speaking, three types of herbal formulas used in TCM: 1. Classic Formulas - these are formulas which TCM practitioners believe have withstood
17324-607: The same name will have the same proportions of ingredients, and manufactured in accordance with the PRC Pharmacopoeia, which is mandated by law. However, in western countries there may be variations in the proportions of ingredients in patent medicines of the same name, and even different ingredients altogether. Several producers of Chinese herbal medicines are pursuing FDA clinical trials to market their products as drugs in U.S. and European markets. Chinese herbal extracts are herbal decoctions that have been condensed into
17466-424: The same reason, which can create inconsistencies and confusion in the creation of medicinals, with the possible danger of poisoning. Edzard Ernst "concluded that adverse effects of herbal medicines are an important albeit neglected subject in dermatology, which deserves further systematic investigation." Research suggests that the toxic heavy metals and undeclared drugs found in Chinese herbal medicines might be
17608-449: The same time. Each pyruvate is then oxidized into acetyl-CoA by the pyruvate dehydrogenase complex , which also generates NADH and carbon dioxide. Acetyl-CoA enters the citric acid cycle, which takes places inside the mitochondrial matrix. At the end of the cycle, the total yield from 1 glucose (or 2 pyruvates) is 6 NADH, 2 FADH 2 , and 2 ATP molecules. Finally, the next stage is oxidative phosphorylation, which in eukaryotes, occurs in
17750-680: The second and third stages, respectively, provide the energy and electrons to drive the synthesis of glucose by fixing atmospheric carbon dioxide into existing organic carbon compounds, such as ribulose bisphosphate (RuBP) in a sequence of light-independent (or dark) reactions called the Calvin cycle . Cell signaling (or communication) is the ability of cells to receive, process, and transmit signals with its environment and with itself. Signals can be non-chemical such as light, electrical impulses , and heat, or chemical signals (or ligands ) that interact with receptors , which can be found embedded in
17892-553: The skin. Their morphological, metabolic, and geographical diversity permits them to play multiple ecological roles: carbon fixation; nitrogen cycling; organic compound turnover; and maintaining microbial symbiotic and syntrophic communities, for example. Eukaryotes are hypothesized to have split from archaea, which was followed by their endosymbioses with bacteria (or symbiogenesis ) that gave rise to mitochondria and chloroplasts, both of which are now part of modern-day eukaryotic cells. The major lineages of eukaryotes diversified in
18034-570: The spine of a dog. Color is not only a valuable means of identifying herbs, but in many cases also provides information about the therapeutic attributes of the herb. For example, yellow herbs are referred to as huang (yellow) or jin (gold). Huang Bai ( Cortex Phellodendri ) means 'yellow fir," and Jin Yin Hua ( Flos Lonicerae ) has the label 'golden silver flower." Unique flavors define specific names for some substances. Gan means 'sweet,' so Gan Cao ( Radix glycyrrhizae )
18176-479: The stroma. This is analogous to the proton-motive force generated across the inner mitochondrial membrane in aerobic respiration. During the third stage of photosynthesis, the movement of protons down their concentration gradients from the thylakoid lumen to the stroma through the ATP synthase is coupled to the synthesis of ATP by that same ATP synthase. The NADPH and ATPs generated by the light-dependent reactions in
18318-447: The teeth, feces, urine, sweat, and organs, but most are no longer in use. Typically, one batch of medicinals is prepared as a decoction of about 9 to 18 substances. Some of these are considered as main herbs, some as ancillary herbs; within the ancillary herbs, up to three categories can be distinguished. Some ingredients are added to cancel out toxicity or side-effects of the main ingredients; on top of that, some medicinals require
18460-434: The term pharmaceutic . Thus, the term medicinal (instead of herb ) is usually preferred as a translation for 藥 (pinyin: yào ). Research into the effectiveness of traditional Chinese herbal therapy is of poor quality and often tainted by bias, with little or no rigorous evidence of efficacy. There are concerns over a number of potentially toxic Chinese herbs. Chinese herbs have been used for centuries. Among
18602-553: The test of time over the centuries, and are mentioned in classical texts, such as the Shanghan Lun . Biology Biology is the scientific study of life . It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of at least one cell that processes hereditary information encoded in genes , which can be transmitted to future generations. Another major theme
18744-471: The third tenet, and by the 1860s most biologists accepted all three tenets which consolidated into cell theory . Meanwhile, taxonomy and classification became the focus of natural historians. Carl Linnaeus published a basic taxonomy for the natural world in 1735, and in the 1750s introduced scientific names for all his species. Georges-Louis Leclerc, Comte de Buffon , treated species as artificial categories and living forms as malleable—even suggesting
18886-453: The time, including plants, animals, and minerals that were believed to have medicinal properties. Li compiled his entries not only from hundreds of earlier works in the bencao medical tradition, but from literary and historical texts. He reasoned that a poem might have better value than a medical work and that a tale of the strange could illustrate a drug's effects. The Ming dynasty emperors did not pay too much attention to his work, and it
19028-439: The total number of chromosomes is maintained. In general, mitosis (division of the nucleus) is preceded by the S stage of interphase (during which the DNA is replicated) and is often followed by telophase and cytokinesis ; which divides the cytoplasm , organelles and cell membrane of one cell into two new cells containing roughly equal shares of these cellular components. The different stages of mitosis all together define
19170-431: The underlying genotype of an organism with a dominant phenotype. A Punnett square can be used to predict the results of a test cross. The chromosome theory of inheritance , which states that genes are found on chromosomes, was supported by Thomas Morgans 's experiments with fruit flies , which established the sex linkage between eye color and sex in these insects. A gene is a unit of heredity that corresponds to
19312-399: The use of other substances as catalysts . Chinese patent medicine ( 中成藥 ; 中成药 ; zhōngchéng yào ) is a kind of traditional Chinese medicine . They are standardized herbal formulas. From ancient times, pills were formed by combining several herbs and other ingredients, which were dried and ground into a powder. They were then mixed with a binder and formed into pills by hand. The binder
19454-656: The various forms of life, from prokaryotic organisms such as archaea and bacteria to eukaryotic organisms such as protists , fungi, plants, and animals. These various organisms contribute to the biodiversity of an ecosystem , where they play specialized roles in the cycling of nutrients and energy through their biophysical environment . The earliest of roots of science, which included medicine, can be traced to ancient Egypt and Mesopotamia in around 3000 to 1200 BCE . Their contributions shaped ancient Greek natural philosophy . Ancient Greek philosophers such as Aristotle (384–322 BCE) contributed extensively to
19596-481: Was a shift in emphasis in treatment over several centuries. A section of the Huangdi Neijing Suwen including Chapter 74 was added by Wang Bing in his 765 edition. In which it says: 主病之謂君，佐君之謂臣，應臣之謂使，非上下三品之謂也。 "Ruler of disease it called Sovereign, aid to Sovereign it called Minister, comply with Minister it called Envoy (Assistant), not upper lower three classes (qualities) it called." The last part
19738-540: Was collated by Zhang Zhongjing , also sometime at the end of the Han dynasty , between 196 and 220 CE. Focusing on drug prescriptions, it was the first medical work to combine Yinyang and the Five Phases with drug therapy. This formulary was also the earliest Chinese medical text to group symptoms into clinically useful "patterns" ( zheng , 證 ) that could serve as targets for therapy. Having gone through numerous changes over time, it now circulates as two distinct books:
19880-969: Was ignored. Li's work contained errors and mistakes due to his limited scientific knowledge at the time. For example, Li claimed that all otters were male and that quicksilver (mercury) was not toxic. The title, translated as " Materia Medica , Arranged according to Drug Descriptions and Technical Aspects", uses two Chinese compound words . Bencao ( Pen-ts'ao ; "roots and herbs; based on herbs, pharmacopeia, materia medica ") combines ben ( 本 'origin, basis') and cao ( 草 'grass, plant, herb'). Gangmu ( Kang-mu ; 'detailed outline; table of contents') combines gang ( kang ; 綱 'main rope, hawser; main threads, essential principles') and mu ( 目 'eye, look; category, division'). The characters 綱 and 目 were later used as ' class ' and ' order ', respectively, in biological classification . Li Shizhen travelled widely for field study, combed through more than 800 works of literature, and compiled material from
20022-434: Was launched in 1990 to map the human genome . All organisms are made up of chemical elements ; oxygen , carbon , hydrogen , and nitrogen account for most (96%) of the mass of all organisms, with calcium , phosphorus , sulfur , sodium , chlorine , and magnesium constituting essentially all the remainder. Different elements can combine to form compounds such as water, which is fundamental to life. Biochemistry
20164-403: Was traditionally honey. Modern teapills, however, are extracted in stainless steel extractors to create either a water decoction or water-alcohol decoction, depending on the herbs used. They are extracted at a low temperature (below 100 °C (212 °F)) to preserve essential ingredients. The extracted liquid is then further condensed, and some raw herb powder from one of the herbal ingredients
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