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Reverse Transcriptase
A reverse transcriptase (RT) is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process termed reverse transcription. Reverse transcriptases are used by viruses such as HIV and hepatitis B to replicate their genomes, by retrotransposon mobile genetic elements to proliferate within the host genome, and by eukaryotic cells to extend the telomeres at the ends of their linear chromosomes. Contrary to a widely held belief, the process does not violate the flows of genetic information as described by the classical central dogma, as transfers of information from RNA to DNA are explicitly held possible. Retroviral RT has three sequential biochemical activities: RNA-dependent DNA polymerase activity, ribonuclease H (RNase H), and DNA-dependent DNA polymerase activity. Collectively, these activities enable the enzyme to convert single-stranded RNA into double-stranded cDNA. In retroviruses and retrotransposons, this cDNA can then integrate into the host genom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the 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 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 are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Wisconsin–Madison
A university () is an educational institution, institution of higher education, higher (or Tertiary education, tertiary) education and research which awards academic degrees in several Discipline (academia), academic disciplines. Universities typically offer both undergraduate education, undergraduate and postgraduate education, postgraduate programs. In the United States, the designation is reserved for colleges that have a graduate school. The word ''university'' is derived from the Latin ''universitas magistrorum et scholarium'', which roughly means "community of teachers and scholars". The first universities were created in Europe by Catholic Church monks. The University of Bologna (''Università di Bologna''), founded in 1088, is the first university in the sense of: *Being a high degree-awarding institute. *Having independence from the ecclesiastic schools, although conducted by both clergy and non-clergy. *Using the word ''universitas'' (which was coined at its foundation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RNA Virus
An RNA virus is a virusother than a retrovirusthat has ribonucleic acid (RNA) as its genetic material. The nucleic acid is usually single-stranded RNA ( ssRNA) but it may be double-stranded (dsRNA). Notable human diseases caused by RNA viruses include the common cold, influenza, SARS, MERS, Covid-19, Dengue Virus, hepatitis C, hepatitis E, West Nile fever, Ebola virus disease, rabies, polio, mumps, and measles. The International Committee on Taxonomy of Viruses (ICTV) classifies RNA viruses as those that belong to ''Group III'', ''Group IV'' or ''Group V'' of the Baltimore classification system. This category excludes ''Group VI'', viruses with RNA genetic material but which use DNA intermediates in their life cycle: these are called retroviruses, including HIV-1 and HIV-2 which cause AIDS. As of May 2020, all known RNA viruses encoding an RNA-directed RNA polymerase are believed to form a monophyletic group, known as the realm '' Riboviria''. The majority of such RNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HIV-1 Reverse Transcriptase With Active Sites
The subtypes of HIV include two major types, HIV type 1 (HIV-1) and HIV type 2 (HIV-2). HIV-1 is related to viruses found in chimpanzees and gorillas living in western Africa, while HIV-2 viruses are related to viruses found in the sooty mangabey, a vulnerable West African primate. HIV-1 viruses can be further divided into groups M, N, O and P. The HIV-1 group M viruses predominate and are responsible for the AIDS pandemic. Group M can be further subdivided into subtypes based on genetic sequence data. Some of the subtypes are known to be more virulent or are resistant to different medications. Likewise, HIV-2 viruses are thought to be less virulent and transmissible than HIV-1 M group viruses, although HIV-2 is also known to cause AIDS. One of the obstacles to treatment of the human immunodeficiency virus (HIV) is its high genetic variability. Major types HIV-1 HIV-1 is the most common and pathogenic strain of the virus. Over 2 million such infections occur annually. Scientists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosomes
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, each chromosome is duplicated (S phase), and both copies are joined by a centromere, resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. The joined copies are now called sis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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