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Double-Helix
In molecular biology, the term double helix refers to the structure formed by double-stranded molecules of nucleic acids such as DNA. The double helical structure of a nucleic acid complex arises as a consequence of its secondary structure, and is a fundamental component in determining its tertiary structure. The structure was discovered by Rosalind Franklin and her student Raymond Gosling, Maurice Wilkins, James Watson, and Francis Crick, while the term "double helix" entered popular culture with the 1968 publication of Watson's '' The Double Helix: A Personal Account of the Discovery of the Structure of DNA''. The DNA double helix biopolymer of nucleic acid is held together by nucleotides which base pair together. In B-DNA, the most common double helical structure found in nature, the double helix is right-handed with about 10–10.5 base pairs per turn. The double helix structure of DNA contains a ''major groove'' and ''minor groove''. In B-DNA the major groove is wider th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features Peer review, peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2022 ''Journal Citation Reports'' (with an ascribed impact factor of 50.5), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in the autumn of 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander MacMillan (publisher), Alexander MacMillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the semi-exclave of Alaska in the northwest and the archipelago of Hawaii in the Pacific Ocean. The United States asserts sovereignty over five Territories of the United States, major island territories and United States Minor Outlying Islands, various uninhabited islands in Oceania and the Caribbean. It is a megadiverse country, with the world's List of countries and dependencies by area, third-largest land area and List of countries and dependencies by population, third-largest population, exceeding 340 million. Its three Metropolitan statistical areas by population, largest metropolitan areas are New York metropolitan area, New York, Greater Los Angeles, Los Angel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerase Chain Reaction
The polymerase chain reaction (PCR) is a method widely used to make millions to billions of copies of a specific DNA sample rapidly, allowing scientists to amplify a very small sample of DNA (or a part of it) sufficiently to enable detailed study. PCR was invented in 1983 by American biochemist Kary Mullis at Cetus Corporation. Mullis and biochemist Michael Smith (chemist), Michael Smith, who had developed other essential ways of manipulating DNA, were jointly awarded the Nobel Prize in Chemistry in 1993. PCR is fundamental to many of the procedures used in genetic testing and research, including analysis of Ancient DNA, ancient samples of DNA and identification of infectious agents. Using PCR, copies of very small amounts of DNA sequences are exponentially amplified in a series of cycles of temperature changes. PCR is now a common and often indispensable technique used in medical laboratory research for a broad variety of applications including biomedical research and forensic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TATA Box
In molecular biology, the TATA box (also called the Goldberg–Hogness box) is a sequence of DNA found in the core promoter region of genes in archaea and eukaryotes. The bacterial homolog of the TATA box is called the Pribnow box which has a shorter consensus sequence. The TATA box is considered a non-coding DNA sequence (also known as a cis-regulatory element). It was termed the "TATA box" as it contains a consensus sequence characterized by repeating T and A base pairs. How the term "box" originated is unclear. In the 1980s, while investigating nucleotide sequences in mouse genome loci, the Hogness box sequence was found and "boxed in" at the -31 position. When consensus nucleotides and alternative ones were compared, homologous regions were "boxed" by the researchers. The boxing in of sequences sheds light on the origin of the term "box". The TATA box was first identified in 1978 as a component of eukaryotic promoters. Transcription is initiated at the TATA box in TA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complementarity (molecular Biology)
In molecular biology, complementarity describes a relationship between two structures each following the lock-and-key principle. In nature complementarity is the base principle of DNA replication and transcription as it is a property shared between two DNA or RNA sequences, such that when they are aligned antiparallel to each other, the nucleotide bases at each position in the sequences will be complementary, much like looking in the mirror and seeing the reverse of things. This complementary base pairing allows cells to copy information from one generation to another and even find and repair damage to the information stored in the sequences. The degree of complementarity between two nucleic acid strands may vary, from complete complementarity (each nucleotide is across from its opposite) to no complementarity (each nucleotide is not across from its opposite) and determines the stability of the sequences to be together. Furthermore, various DNA repair functions as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nobel Prize In Physiology Or Medicine
The Nobel Prize in Physiology or Medicine () is awarded yearly by the Nobel Assembly at the Karolinska Institute for outstanding discoveries in physiology or medicine. The Nobel Prize is not a single prize, but five separate prizes that, according to Alfred Nobel's 1895 will, are awarded "to those who, during the preceding year, have conferred the greatest benefit to humankind". Nobel Prizes are awarded in the fields of Physics, Medicine or Physiology, Chemistry, Literature, and Peace. The Nobel Prize is presented annually on the anniversary of Alfred Nobel's death, 10 December. As of 2024, 115 Nobel Prizes in Physiology or Medicine have been awarded to 229 laureates, 216 men and 13 women. The first one was awarded in 1901 to the German physiologist, Emil von Behring, for his work on serum therapy and the development of a vaccine against diphtheria. The first woman to receive the Nobel Prize in Physiology or Medicine, Gerty Cori, received it in 1947 for her role in elucida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triple-stranded DNA
Triple-stranded DNA (also known as H-DNA or Triplex-DNA) is a DNA structure in which three oligonucleotides wind around each other and form a triple helix. In triple-stranded DNA, the third strand binds to a Nucleic acid double helix#Helix geometries, B-form DNA (via Base pair, Watson–Crick base-pairing) double helix by forming Hoogsteen base pairs or reversed Hoogsteen hydrogen bonds. Structure Examples of triple-stranded DNA from natural sources with the necessary combination of base composition and structural elements have been described, for example in Satellite DNA. Hoogsteen base pairing A thymine (T) nucleobase can bind to a Base pair, Watson–Crick base-pairing of T-A by forming a Hoogsteen base pair, Hoogsteen hydrogen bond. The thymine hydrogen bonds with the adenosine (A) of the original double-stranded DNA to create a T-A*T base-triplet. Intermolecular and intramolecular interactions There are two classes of triplex DNA: intermolecular and intramolecula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Corey
Robert Brainard Corey (August 19, 1897 – April 23, 1971) was an American biochemist, mostly known for his role in discovery of the α-helix and the β-sheet with Linus Pauling. Also working with Pauling was Herman Branson. Their discoveries were remarkably correct, with even the bond lengths being accurate until about 40 years later. The α-helix and β-sheet are two structures that are now known to form the backbones of many proteins. Academic training A childhood polio survivor, Corey received his undergraduate degree from the University of Pittsburgh, and his Ph.D. in chemistry from Cornell University (Marsh, p. 52-53). The findings of α-helix and β-sheet At Caltech, the trio (Pauling, Corey and Branson) published a series of articles in the Proceedings of the National Academy of Sciences. Pauling, L., and R. B. Corey. 1953. A proposed structure for the nucleic acids. Proc. Natl. Acad. Sci. U.S.A. 39:84-97. Pauling, L., R. B. Corey, and H. R. Branson. 1951. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linus Pauling
Linus Carl Pauling ( ; February 28, 1901August 19, 1994) was an American chemist and peace activist. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. ''New Scientist'' called him one of the 20 greatest scientists of all time. For his scientific work, Pauling was awarded the Nobel Prize in Chemistry in 1954. For his peace activism, he was awarded the Nobel Peace Prize in 1962. He is one of five people to have Nobel Prize#Multiple laureates, won more than one Nobel Prize. Of these, he is the only person to have been awarded two unshared Nobel Prizes, and one of two people to be awarded Nobel Prizes in different fields, the other being Marie Curie. Pauling was one of the founders of the fields of quantum chemistry and molecular biology. His contributions to the theory of the chemical bond include the concept of orbital hybridisation and the first accurate scale of electronegativity, electronegativities of the elements. Pauling also wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erwin Chargaff
Erwin Chargaff (11 August 1905 – 20 June 2002) was an Austro-Hungarian-born American biochemist, writer, and professor of biochemistry at Columbia University medical school. A Bucovinian Jew who immigrated to the United States during the Nazi Germany, Nazi regime, he penned a well-reviewed autobiography, ''Heraclitean Fire: Sketches from a Life Before Nature''. Through careful experimentation, Chargaff discovered two rules, called Chargaff's rules, which helped lead to the discovery of the double helix structure of DNA. Early life Chargaff was born on 11 August 1905 to a Jewish family in Czernowitz, Duchy of Bukovina, Austria-Hungary, which is now Chernivtsi, Ukraine. At the outbreak of World War I, his family moved to Vienna, where he attended the Maximiliansgymnasium (now the Gymnasium Wasagasse). He then went on to the TU Wien, Vienna College of Technology (''Technische Hochschule Wien'') where he met his future wife Vera Broido. From 1924 to 1928, Chargaff studied chemist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
