Copyright © Philip M. Parker, INSEAD. Terms of Use.
Definition: Molecular Biology |
Molecular BiologyNoun1. The branch of biology that studies the structure and activity of macromolecules essential to life (and especially with their genetic role). Source: WordNet 1.7.1 Copyright © 2001 by Princeton University. All rights reserved. |
Crosswords: Molecular Biology |
| English words defined with "molecular biology": biotechnology. (references) |
| Specialty definitions using "molecular biology": Biofilms ♦ Chromosomes, Yeast Artificial, Computational Biology, Cyanogen Bromide ♦ DNA computing, DNA Primers ♦ Epidemiology, Molecular ♦ Molecular Sequence Data ♦ Pili, Sex ♦ Receptors, Cell Surface, Receptors, Cholinergic, Receptors, Dopamine D1, Receptors, Dopamine D2, Receptors, Muscarinic, Receptors, Nicotinic, Receptors, Serotonin, Roche Institute of Molecular Biology. (references) |
(From Wikipedia, the free Encyclopedia)
Molecular biology is the study of biology at a molecular level and was established in the 1930s. The field overlaps with other areas of biology, particularly genetics and biochemistry. Molecular biology chiefly concerns itself with understanding the interactions between the various systems of a cell, including the interrelationship of DNA, RNA and protein synthesis and learning how these interactions are regulated.
Writing in Nature, W.T. Astbury described molecular biology as:
"... not so much a technique as an approach, an approach from the viewpoint of the so-called basic sciences with the leading idea of searching below the large-scale manifestations of classical biology for the corresponding molecular plan. It is concerned particularly with the forms of biological molecules and ..... is predominantly three-dimensional and structural - which does not mean, however, that it is merely a refinement of morphology - it must at the same time inquire into genesis and function" [Nature 190, 1124 (1961)]
Researchers in molecular biology use specific techniques native to molecular biology (see Techniques section later in article), but increasingly combine these with techniques and ideas from genetics, biochemistry and biophysics. There is not a hard-line between these disciplines as there once was. The following figure is a schematic that depicts one possible view of the relationship between the fields:
Increasingly many other fields of biology focus on molecules, either directly studying their interactions in their own right such as in cell biology and developmental biology, or indirectly, where the techniques of molecular biology are used to infer historical attributes of populations or species, as in fields in evolutionary biology such as population genetics and phylogenetics. There is also a long tradition of studying biomolecules "from the ground up" in biophysics.
Since the late 1950s and early 1960s, molecular biologists have learned to characterise, isolate, and manipulate the molecular components of cells and organisms. These components include DNA, the repository of genetic information; RNA, a close relative of DNA whose functions range from serving as a temporary working copy of DNA to actual structural and enzymatic functions as well as a functional and structural part of the translational apparatus; and proteins, the major structural and enzymatic type of molecule in cellss.
One of the most basic techniques of molecular biology to study protein function is expression cloning. In this technique, DNA coding for a protein of interest is cloned (using PCR and/or restriction enzymes) into a plasmid (known as an expression vector). This plasmid may have special promoter elements to drive production of the protein of interest, and may also have antibiotic resistance markers to help follow the plasmid.
This plasmid can be inserted into either bacterial or animal cells. Introducing DNA into bacterial cells is called transformation, and can be effected by several methods, including electroporation, microinjection and chemically. Introducing DNA into eukaryotic cells, such as animal cells, is called transfection. Several different transfection technqiues are available, including calcium phosphate transfection, liposome transfection, and proprietary transfection reagents such as Fugene. DNA can also be introduced into cells using viruses as a carrier. In such cases, the technique is called viral transduction, and the cells are said to be transduced.
In either case, DNA coding for a protein of interest is now inside a cell, and the protein can now be expressed.. A variety of systems, such as inducible promoters and specific cell-signaling factors, are available to help express the protein of interest at high levels. Large quantities of a protein can then be extracted from the bacterial or eukaryotic cell. The protein can be tested for enzymatic activity under a variety of situations, the protein may be crystallized so its tertiary structure can be studied, or, in the pharmaceutical industry, the activity of new drugs against the protein can be studied.
Main article: Polymerase chain reaction
The polymerase chain reaction is an extremely versatile technique for copying DNA and RNA. In brief, PCR allows a single DNA to be copied (millions of times), or altered in predetermined ways. For example, PCR can be used to introduce restriction enzyme sites, or to mutate particular bases of DNA. PCR can also be used to determine whether a particular DNA fragment is found in a cDNA library.
Main article: Gel electrophoresis
Gel electrophoresis is one of the principal tools of molecular biology. The basic principle is that DNA, RNA, and proteins can all be separated using an electric field. In agarose gel electrophoresis, DNA and RNA can be separated based on size by running the DNA through an agarose gel. Proteins can be separated based on size using an SDS-PAGE gel. Proteins can also be separated based on their electric charge, using what is known as an isoelectric gel.
Main article: Western blot
Antibodies to any protein can be created by injecting small amounts of protein into an animal such as a mouse, rabbit, sheep, or donkey. These antibodies can be used for a variety of analytical and preprative techniques.
In Western blotting, proteins are first separated by size, on a thin gel sandwiched between two glass plates. The gels, called an SDS-PAGE (for Sodium Dodecyl Sulfate Poly-Acrylamide Gel Electrophoresis). The proteins on the gel are then transferred to a PVDF, nitrocellulose, nylon or other support membrane. This membrane can then be probed with solutions of antibodies. Antibodies that specifically bind to the protein of interest can then be visualized by a variety of techniques, including chemoluminescence or radioactivity.
Antibodies can also be used to purify proteins. Antibodies to a protein are generated and are often then coupled to "beads". After the antibody has bound to the protein of interest, this antibody-protein complex can be separated from all other proteins by centrifugation. During centrifugation, the beads, to which the antibody is coupled, will pellet (bringing the protein of interest down with it) whereas all other proteins will remain in the solution. Alternatively, antibodies coupled to a solid support matrix like Sephadex or Sepharose beads, for example, can be used to remove a protein of interest from a complex solution. After washing unbound and non-specifically bound materials away from the "beads", the protein of interest is then eluted from the matrix, usually by adding a solution with a high salt concentration, or by varying the pH of the solution in which the matrix is contained. The beads can either be suspended in solution (batch processing) or packed into a tube (column processing).
Relationship to other "molecular-scale" biological sciences
Schematic relationship between biochemistry, genetics and molecular biology
Much of the work in molecular biology is quantitative, and recently much work has been done at the interface of molecular biology and computer science in bioinformatics and computational biology. As of the early 2000s, the study of gene structure and function, molecular genetics, has been amongst the most prominent sub-field of molecular biology.Techniques of molecular biology
Expression cloning
Polymerase chain reaction (PCR)
Gel electrophoresis
Western blotting and immunochemistry
Further reading
Related topics
Notable molecular biologists
See also
Source: adapted by the editor from Wikipedia, the free encyclopedia under a copyleft GNU Free Documentation License (GFDL) from the article "Molecular biology."
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Source: compiled by the editor from various references; see credits. | |||
| Thumbnail | Description & Credit | Thumbnail | Description & Credit |
 | Pictured is a molecular biology lab at MIT where a woman scientist works with an apparatus that counts radioactivity incorporated into DNA. She is shown here checking samples in the research work she is performing. Credit: Linda Bartlett (photographer). |  | Purified DNA, fluorescing orange under UV light, is extracted and used for molecular biology studies. The purified DNA, in a cesium chloride gradient, binds to the ethidium bromide dye which absorbs UV light and makes the DNA fluoresce orange. This visualization of a single band of DNA aids in the isolation and extraction of the DNA for future molecular biology studies. Credit: Mike Mitchell (photographer). |
 | The Laboratory of Molecular Biology. / Photographed by Thomas Joy. Credit: National Library of Medicine. |  | Impact of Molecular Biology on Biomedical Research. Credit: National Library of Medicine. |
Source: pictures compiled by the editor from various references; see picture credits. | |||
| Subject | Topic | Quote |
Health | Applying tools of molecular biology. (references) | |
Molecular biology has given us a foothold to understand what goes wrong. (references) | ||
Investigation of genetic bases for susceptibility to NIHL, using contemporary techniques, including molecular biology. (references) | ||
Business | To support the development of biotechnology, the Academia Sinica set up the Institute of Molecular Biology in 1986 and the Institute of Biomedical Sciences in 1987. Both of these organizations are important users of biotech products. (references) | |
Currently linear accelerators of 6mev are used, and these will need to be updated soon. U.S. suppliers can also look forward to more demand in nuclear diagnostic equipment, scintigraphic equipment and molecular biology diagnostic instruments. (references) | ||
Economic History | Australia | Australia's scientific excellence is founded upon its expertise in a range of disciplines, including genetics, molecular biology, immunology, and plant and agricultural biotechnology. (references) |
Source: compiled by the editor from ICON Group International, Inc.; see credits. | ||
Expression using "molecular biology": Roche Institute of Molecular Biology. Additional references. | |
| Source: compiled by the editor from various references; see credits. |
| The following statistics estimate the number of searches per day across the major English-language search engines as identified by various trade publications. Hyperlinks lead to commercial use of the expression at Amazon.com. |
| Expression | Frequency per Day |
molecular biology | 267 |
molecular biology of the cell | 49 |
molecular biology journal | 30 |
molecular biology protocol | 27 |
biochemistry and molecular biology | 15 |
current protocol in molecular biology | 14 |
plant molecular biology | 13 |
molecular biology job | 12 |
molecular biology technique | 8 |
molecular biology tool | 8 |
molecular biology dictionary | 7 |
| Source: compiled by the editor from various references; see credits. | |
| Language | Translations for "molecular biology"; alternative meanings/domain in parentheses. | ||||||||||||||||||||||
Danish | molekylaer biologi, molekularbiologi. (various references) | ||||||||||||||||||||||
Dutch | moleculaire biologie. (various references) | ||||||||||||||||||||||
Finnish | molekyylibiologia. (various references) | ||||||||||||||||||||||
French | biologie moléculaire. (various references) | ||||||||||||||||||||||
German | Molekularbiologie. (various references) | ||||||||||||||||||||||
Greek | μοριακή βιολογία. (various references) | ||||||||||||||||||||||
Italian | biologia molecolare. (various references) | ||||||||||||||||||||||
Japanese Kanji | 分子"物学 . (various references) | ||||||||||||||||||||||
Japanese Katakana | ぶ"しせいぶつがく. (various references) | ||||||||||||||||||||||
Pig Latin | olecularmay iologybay biologia molecular. (various references) biología molecular. (various references) molekylärbiologi. (various references) | ||||||||||||||||||||||
Scrabble® Enable2K-Verified Anagrams | |
| Words within the letters "a-b-c-e-g-i-l-l-l-m-o-o-o-r-u-y" | |
-3 letters: bimolecularly, embryological. | |
-4 letters: biomolecular. | |
-5 letters: aerobiology, bimolecular, bryological, molecularly. | |
| Source: compiled by the editor from various references; see credits. SCRABBLE® is a registered trademark. All intellectual property rights in and to the game are owned in the U.S.A and Canada by Hasbro Inc., and throughout the rest of the world by J.W. Spear & Sons Limited of Maidenhead, Berkshire, England, a subsidiary of Mattel Inc. Mattel and Spear are not affiliated with Hasbro. | |
Hexadecimal (or equivalents, 770AD-1900s) (references)4D 6F 6C 65 63 75 6C 61 72 42 69 6F 6C 6F 67 79 |
| Leonardo da Vinci (1452-1519; backwards) (references)
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Binary Code (1918-1938, probably earlier) (references)01001101 01101111 01101100 01100101 01100011 01110101 01101100 01100001 01110010 00100000 01000010 01101001 01101111 01101100 01101111 01100111 01111001 |
HTML Code (1990) (references)M o l e c u l a r   B i o l o g y |
ISO 10646 (1991-1993) (references)004D 006F 006C 0065 0063 0075 006C 0061 0072 0042 0069 006F 006C 006F 0067 0079 |
Encryption (beginner's substitution cypher): (references)478178716987786784236758178817391 |
| Language | Coverage | Language Translations |
Danish | ordbog, deskriptordefinition, oversættelse | tanskalainen, danois, dänisch, δανικόσ, δανόσ, danese, dinamarquês, danés, dansk |
Dutch | woordenboek, definitie, translatie | hollandsk, hollantilainen, néerlandais, holländisch, ολλανδικόσ, ολλανδόσ, olandese, holandês, holandés, holländsk |
Finnish | määritelmä, translaatio, taajuusmuutos | suomi, suomalainen, finnois, Finlandaise, finlandais, finnisch, φινλανδικόσ, finlandese, finlandês, finês, finlandés, finés, finsk |
French | dictionnaire, définition, traduction | ranskalainen, français, französisch, γαλλικόσ, γαλλική γλώσσα, γαλλίδα, γάλλοσ, francese, フレコン化 , 仏文 , フランス" , 仏 , ふつぶ", ふつ, フレンチ , フランセ , francês, francés, fransk, franska |
German | Übersetzung, Wörterbuch, Definition | tysker, Duitse, saksalainen, allemand, "ερμανός, tedesco, ジプシー音楽 , ジャーマン , alemão, alemán, tysk |
Greek | λεξικό, ορισμός, μετάφραση | græker, kreikkalainen, grec, grieche, ελληνικόσ, 'Ελληνας, greco, ギリシア語 , ギリシア", grego, griego, grek |
Italian | dizionario, definizione, traduzione | italiener, italialainen, italien, italienisch, Ιταλός, italiano, italiensk, italienska, italienare |
Japanese Kanji | 辭典 , 辞典 , 字引 , 辞林 , 字書 , ディーゼル電気車 , 言海 , 辞彙 , 辞書 , 確定 , ディーゼル電気車 , デ'ドロ酢酸 , 翻訳 | japanilainen, Japonais, japaner, japanisch, ιαπωνικόσ, Ιάπωνας· "ιαπωνέζος, ιάπωνεσ, ιάπων, ιαπωνικά, giapponese, 邦語 , 邦人 , ジャスミン茶 , ほう", ジャパニーズ , ほうじ", japonês, japonés, japansk |
Japanese Katakana | じい, じびき, じて", ディクショナリー , じり", じしょ, '"かい, ディクショナリ , デフィニション , ディフィニション , ていぎ, かくてい, へい"ういどう, やくじゅつ, トランスレーション , やくしょ, やくしゅつ, "うどく, ほ"やく, ほ"やくしょ | japanilainen, Japonais, japaner, japanisch, ιαπωνικόσ, Ιάπωνας· "ιαπωνέζος, ιάπωνεσ, ιάπων, ιαπωνικά, giapponese, 邦語 , 邦人 , ジャスミン茶 , ほう", ジャパニーズ , ほうじ", japonês, japonés, japansk |
Portuguese | dicionário, definição, tradução | portugiser, portugalilainen, portugais, portugiesisch, πορτογάλοσ, ορτογάλος, portoghese, ポルトガル語 , ポルトガル", português, portugués, portugis |
Spanish | diccionario, definición, traducción | Spaans, espanjalainen, espagnol, spanisch, ισπανικά, ισπανικόσ, ισπανοί, spagnolo, スペイン語 , スパイ罪 , スペイン", スパニッシュ , espanhol, español, spanska språk, spansk |
Swedish | ordbok, lexikon, översättning | Zweeds, ruotsalainen, suédois, schwedisch, σουηδικόσ, σουηδικά, svedese, スウェーデン語 , スウェーデン", sueco, svensk |
English | Dictionary, Definition, Translation | englantia, englantilainen, anglais, englisch, εγγλέζοσ, αγγλικόσ, inglese, inglês, inglés, engelsk |
| 1. Definition 2. Crosswords 3. Usage: Commercial 4. Images: Photo Album | 5. Quotations: Non-fiction 6. Expressions 7. Expressions: Internet 8. Translations: Modern | 9. Anagrams 10. Orthography 11. Bibliography |
Copyright © Philip M. Parker, INSEAD. Terms of Use.
