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DNA Re-replication
DNA re-replication (or simply rereplication) is an undesirable and possibly fatal occurrence in eukaryotic cells in which the genome is replicated more than once per cell cycle. Rereplication is believed to lead to genomic instability and has been implicated in the pathologies of a variety of human cancers. To prevent rereplication, eukaryotic cells have evolved multiple, overlapping mechanisms to inhibit chromosomal DNA from being partially or fully rereplicated in a given cell cycle. These control mechanisms rely on cyclin-dependent kinase (CDK) activity. DNA replication control mechanisms cooperate to prevent the relicensing of replication origins and to activate cell cycle and DNA damage checkpoints. DNA rereplication must be strictly regulated to ensure that genomic information is faithfully transmitted through successive generations. Initiating Replication at Origins Replication of DNA always begins at an origin of replication. In yeast, the origins contain autonomousl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overview Of Chromosome Duplication In The Cell Cycle
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Overview may refer to: * Overview article, an artícle that summarizes the current state of understanding on a topic * Overview map, generalised view of a geographic area See also * Summary (other) * Outline (list) * ''A Brief Overview'' * Overview and Scrutiny * Overview effect The overview effect is a cognitive shift reported by some astronauts while viewing the Earth from space. Researchers have characterized the effect as "a state of awe with self-transcendent qualities, precipitated by a particularly striking visu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AAA Proteins
AAA, Triple A, or Triple-A is a three-letter initialism or abbreviation which may refer to: Airports * Anaa Airport in French Polynesia (IATA airport code AAA) * Logan County Airport (Illinois) (FAA airport code AAA) Arts, entertainment, and media Gaming * AAA (video game industry) - a category of high budget video games *'' TripleA'', an open source wargame Music Groups and labels * AAA (band), a Japanese pop band * Against All Authority (''-AAA-''), an American ska-punk band * Acid Angel From Asia ''(AAA)'' the first sub-unit of K-pop girl group TripleS referred to as "AVA" * Triple A (musical group), a Dutch trance group Works * Song on ''City'' (Strapping Young Lad album) * ''A.A.A'' (EP), by Nigerian band A.A.A Other music * Triple A or Adult Alternative Songs, a record chart Other uses in arts, entertainment, and media * Adult album alternative, a radio format * AAA, the production code for the 1970 ''Doctor Who'' serial ''Spearhead from Space'' * (''Aces o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorylation
In chemistry, phosphorylation is the attachment of a phosphate group to a molecule or an ion. This process and its inverse, dephosphorylation, are common in biology and could be driven by natural selection. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License. Protein phosphorylation often activates (or deactivates) many enzymes. Glucose Phosphorylation of sugars is often the first stage in their catabolism. Phosphorylation allows cells to accumulate sugars because the phosphate group prevents the molecules from diffusing back across their transporter. Phosphorylation of glucose is a key reaction in sugar metabolism. The chemical equation for the conversion of D-glucose to D-glucose-6-phosphate in the first step of glycolysis is given by :D-glucose + ATP → D-glucose-6-phosphate + ADP : ΔG° = −16.7 kJ/mol (° indicates measurement at standard condition) Hepatic cells are freely permeable to glucose, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saccharomyces Cerevisiae
''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungus microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have been originally isolated from the skin of grapes. It is one of the most intensively studied eukaryotic model organisms in molecular biology, molecular and cell biology, much like ''Escherichia coli'' as the model bacteria, bacterium. It is the microorganism behind the most common type of fermentation (biochemistry), fermentation. ''S. cerevisiae'' cells are round to ovoid, 5–10 micrometre, μm in diameter. It reproduces by budding. Many proteins important in human biology were first discovered by studying their Homology (biology), homologs in yeast; these proteins include cell cycle proteins, signaling proteins, and protein-processing enzymes. ''S. cerevisiae'' is currently the only yeast cell known to have Berkeley body, Berkeley bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G1/S Transition
The G1/S transition is a stage in the cell cycle at the boundary between the G1 phase, in which the cell grows, and the S phase, during which DNA is replicated. It is governed by cell cycle checkpoints to ensure cell cycle integrity and the subsequent S phase can pause in response to improperly or partially replicated DNA. During this transition the cell makes decisions to become quiescent (enter G0), differentiate, make DNA repairs, or proliferate based on environmental cues and molecular signaling inputs. The G1/S transition occurs late in G1 and the absence or improper application of this highly regulated check point can lead to cellular transformation and disease states such as cancer During this transition, G1 cyclin D-Cdk4/6 dimer phosphorylates retinoblastoma releasing transcription factor E2F, which then drives the transition from G1 to S phase. The G1/S transition is highly regulated by transcription factor p53 in order to halt the cell cycle when DNA is damaged. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Licensing Factor
A licensing factor is a protein or complex of proteins that allows an origin of replication to begin DNA replication at that site. Licensing factors primarily occur in eukaryotic cells, since bacteria use simpler systems to initiate replication. However, many archaea use homologues of eukaryotic licensing factors to initiate replication. Function Origins of replication represent start sites for DNA replication and so their "firing" must be regulated to maintain the correct karyotype of the cell in question. The origins are required to fire only once per cell cycle, an observation that led to the postulated existence of licensing factors by biologists in the first place. If the origins were not carefully regulated then DNA replication could be restarted at that origin giving rise to multiple copies of a section of DNA. This could be damaging to cells and could have detrimental effects on the organism as a whole. The control that licensing factors exert over the cycle represents a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inhibition Of Pre-RC Assembly
Inhibitor or inhibition may refer to: In biology * Enzyme inhibitor, a substance that binds to an enzyme and decreases the enzyme's activity * Reuptake inhibitor, a substance that increases neurotransmission by blocking the reuptake of a neurotransmitter * Lateral inhibition, a neural mechanism that increases contrast between active and (neighbouring) inactive neurons * Inhibitory postsynaptic potential, a synaptic potential that decreases the firing of a neuron In chemistry * Corrosion inhibitor, a substance that decreases the rate of metal oxidation * Reaction inhibitor, a substance that prevents or decreases the rate of a chemical reaction * Polymerisation inhibitor, a substance that inhibits unwanted polymerisation of monomers In psychology * Cognitive inhibition, the mind's ability to tune out irrelevant stimuli ** Inhibitory control, a cognitive process that permits an individual to inhibit their impulses * Inhibition of return, a feature of attention * Inhibition theor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Origin Licensing
Origin(s) or The Origin may refer to: Arts, entertainment, and media Comics and manga * ''Origin'' (comics), a Wolverine comic book mini-series published by Marvel Comics in 2002 * ''The Origin'' (Buffy comic), a 1999 ''Buffy the Vampire Slayer'' comic book series * Origins (''Judge Dredd'' story), a major ''Judge Dredd'' storyline running from 2006 through 2007 * ''Origin'' (manga), a 2016 manga by Boichi * '' Mobile Suit Gundam: The Origin'', a 2002 manga by Yoshikazu Yasuhiko * '' Wolverine: Origins'', a Marvel Comics series Films and television * ''Origin'' (TV series), 2018 science-fiction TV series * "Origin" (''Angel''), a fifth-season episode of ''Angel'' * '' Origin: Spirits of the Past'', a 2006 anime movie also known as ''Gin-iro no Kami no Agito'' * Origin (''Stargate''), the religion of the Ori * "Origin" (''Stargate SG-1''), a ninth-season episode of ''Stargate SG-1'' * '' X-Men Origins: Wolverine'', a 2009 superhero film, prequel to the ''X-Men'' film tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitosis
In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintained. Therefore, mitosis is also known as equational division. In general, mitosis is preceded by S phase of interphase (during which DNA replication occurs) 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 altogether define the mitotic (M) phase of an animal cell cycle—the division of the mother cell into two daughter cells genetically identical to each other. The process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next. These stages are preprophase (specific to plant cells), prophase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Replication Fork
In molecular biology, DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inheritance. This is essential for cell division during growth and repair of damaged tissues, while it also ensures that each of the new cells receives its own copy of the DNA. The cell possesses the distinctive property of division, which makes replication of DNA essential. DNA is made up of a double helix of two complementary strands. The double helix describes the appearance of a double-stranded DNA which is thus composed of two linear strands that run opposite to each other and twist together to form. During replication, these strands are separated. Each strand of the original DNA molecule then serves as a template for the production of its counterpart, a process referred to as semiconservative replication. As a result of semi-conservative rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Helicase
Helicases are a class of enzymes thought to be vital to all organisms. Their main function is to unpack an organism's genetic material. Helicases are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two hybridized nucleic acid strands (hence '' helic- + -ase''), using energy from ATP hydrolysis. There are many helicases, representing the great variety of processes in which strand separation must be catalyzed. Approximately 1% of eukaryotic genes code for helicases. The human genome codes for 95 non-redundant helicases: 64 RNA helicases and 31 DNA helicases. Many cellular processes, such as DNA replication, transcription, translation, recombination, DNA repair, and ribosome biogenesis involve the separation of nucleic acid strands that necessitates the use of helicases. Some specialized helicases are also involved in sensing of viral nucleic acids during infection and fulfill a immunological function. Function Helicases are of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minichromosome Maintenance
The minichromosome maintenance protein complex (MCM) is a DNA helicase essential for genomic DNA replication. Eukaryotic MCM consists of six gene products, Mcm2–7, which form a heterohexamer. As a critical protein for cell division, MCM is also the target of various checkpoint pathways, such as the S-phase entry and S-phase arrest checkpoints. Both the loading and activation of MCM helicase are strictly regulated and are coupled to cell growth cycles. Deregulation of MCM function has been linked to genomic instability and a variety of carcinomas. History and structure The minichromosome maintenance proteins were named after a yeast genetics screen for mutants defective in the regulation of DNA replication initiation. The rationale behind this screen was that if replication origins were regulated in a manner analogous to transcription promoters, where transcriptional regulators showed promoter specificity, then replication regulators should also show origin specificity. Since ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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