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#ALIH [[Biologi molekuler]]
'''Biologi molekular''' atau '''biologi molekul''' merupakan salah satu cabang [[biologi]] yang merujuk kepada pengkajian mengenai [[kehidupan]] pada skala [[molekul]]. Ini termasuk penyelidikan tentang interaksi molekul dalam benda hidup dan kesannya, terutama tentang interaksi berbagai sistem dalam [[sel]], termasuk interaksi [[DNA]], [[RNA]], dan [[sintesis protein]], dan bagaimana interaksi tersebut diatur. Bidang ini bertumpang tindih dengan bidang [[biologi]] (dan [[kimia]]) lainnya, terutama [[genetika]] dan [[biokimia]].
==Keterkaitan dengan ilmu-ilmu hayati "skala-molekul" lainnya==
Para peneliti biologi molekular menggunakan teknik-teknik khusus yang khas biologi molekular (lihat subbab ''[[#Teknik-teknik biologi molekular|Teknik]]'' di bagian lain artikel ini), namun kini semakin memadukan teknik-teknik tersebut dengan teknik dan gagasan-gagasan dari [[genetika]] dan [[biokimia]]. Tidak terdapat lagi garis tegas yang memisahkan disiplin-disiplin ilmu ini seperti sebelumnya. Secara umum keterkaitan bidang-bidang tersebut dapat digambarkan sebagai berikut:
*''[[Biokimia]]'' merupakan telaah zat-zat kimia dan proses-proses vital yang berlangsung pada [[makhluk hidup]].
*''[[Genetika]]'' merupakan telaah atas efek perbedaan genetik pada makhluk hidup (misalnya telaah mengenai [[mutan]]).
*''Biologi molekular'' merupakan telaah dalam skala molekul atas proses [[replikasi]], [[transkripsi]], dan [[translasi]] [[bahan genetik]].
Semakin banyak bidang biologi lainnya yang memfokuskan diri pada [[molekul]], baik secara langsung mempelajari interaksi molekular dalam bidang mereka sendiri seperti pada [[biologi sel]] dan [[biologi perkembangan]], maupun secara tidak langsung (misalnya dengan menggunakan teknik biologi molekular untuk menyimpulkan ciri-ciri historis [[populasi]] atau [[spesies]]) seperti pada [[genetika populasi]] dan [[filogenetika]].
==Teknik-teknik biologi molekular==
===Kloning ekspresi===
<!--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 [[clone]]d (using [[PCR]] and/or [[restriction enzyme]]s) 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 [[Eukaryote|eukaryotic]] cells, such as animal cells, is called transfection. Several different transfection techniques 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.
===Polymerase chain reaction (PCR)===
''Main article:'' [[Polymerase chain reaction]]
The [[polymerase chain reaction]] is an extremely versatile technique for copying DNA. In brief, PCR allows a single DNA sequence 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 (change) particular bases of DNA. PCR can also be used to determine whether a particular DNA fragment is found in a [[cDNA]] [[library (biology)|library]].
===Elektroforesis gel===
''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...
===''Northern Blotting''===
''Main article:'' [[Northern blot]]
The [[northern_blot|Northern Blot]] is used to study the expression patterns a specific type of RNA molecule as relative comparison among of a set of different samples of RNA. It is essentially a combination of denaturing RNA Gel electrophoresis, and a blot. In this process RNA is separated based on size and is then transfered to a membrane that is then probed with the a labeled complement of a sequence of interest. The results may be visualized through a variety of ways depending on the label used, however, most result in the revelation of bands representing the sized of the RNA detected in sample. The intensity of these bands is related to the amount of the target RNA in the samples analyzed. The procedure is commonly used to study when and how much gene expressing is occurring by measuring how much of that RNA is present in different samples. It is one of the most basic tools for determing at what time certain genes are expressed in living tissues.
===''Western blotting'' dan imunokimia===
''Main article:'' [[Western blot]]
Antibodies to most proteins can be created by injecting small amounts of the 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 blot]]ting, proteins are first separated by size, in a thin gel sandwiched between two glass plates. This technique is called SDS-PAGE (for Sodium Dodecyl Sulfate Poly-Acrylamide Gel Electrophoresis). The proteins in 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).-->
[[Kategori:Biologi molekular]]
{{stub}}
[[cs:Molekulární biologie]]
[[de:Molekularbiologie]]
[[el:Μοριακή Βιολογία]]
[[en:Molecular biology]]
[[eo:Molekulara Biologio]]
[[es:Biología molecular]]
[[et:Molekulaarbioloogia]]
[[fr:Biologie moléculaire]]
[[fy:Molekulêre biology]]
[[he:ביולוגיה מולקולרית]]
[[hr:Molekularna biologija]]
[[hu:Molekuláris biológia]]
[[ja:分子生物学]]
[[ko:분자생물학]]
[[lb:Molekularbiologie]]
[[ms:Biologi skala molekul]]
[[nl:Moleculaire biologie]]
[[pl:Biologia molekularna]]
[[ru:Молекулярная биология]]
[[sv:Molekylärbiologi]]
[[th:อณูชีววิทยา]]
[[vi:Sinh học phân tử]]
[[zh:分子生物学]]
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