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  2. Cell theory - Wikipedia

    en.wikipedia.org/wiki/Cell_theory

    From these conclusions about plants and animals, two of the three tenets of cell theory were postulated. 1. All living organisms are composed of one or more cells 2. The cell is the most basic unit of life. Schleiden's theory of free cell formation through crystallization was refuted in the 1850s by Robert Remak, Rudolf Virchow, and Albert ...

  3. Phosgene - Wikipedia

    en.wikipedia.org/wiki/Phosgene

    Phosgene is a planar molecule as predicted by VSEPR theory. The C=O distance is 1.18 Å , the C−Cl distance is 1.74 Å and the Cl−C−Cl angle is 111.8°. [ 10 ] Phosgene is a carbon oxohalide and it can be considered one of the simplest acyl chlorides, being formally derived from carbonic acid .

  4. Error catastrophe - Wikipedia

    en.wikipedia.org/wiki/Error_catastrophe

    However, given the criticism of the basic assumption of the mathematical model, this approach is problematic. [ 8 ] The result introduces a Catch-22 mystery for biologists, Eigen's paradox : in general, large genomes are required for accurate replication (high replication rates are achieved by the help of enzymes ), but a large genome requires ...

  5. Threshold model - Wikipedia

    en.wikipedia.org/wiki/Threshold_model

    The liability-threshold model is a threshold model of categorical (usually binary) outcomes in which a large number of variables are summed to yield an overall 'liability' score; the observed outcome is determined by whether the latent score is smaller or larger than the threshold. The liability-threshold model is frequently employed in ...

  6. Danger model - Wikipedia

    en.wikipedia.org/wiki/Danger_model

    According to this theory, the chief cell of the immune system is the B cell, activated by recognizing non-self structures. Later research showed that B cell activation is reliant on CD4+ T helper cells and a co-stimulatory signal from an antigen-presenting cell (APC).

  7. Error threshold (evolution) - Wikipedia

    en.wikipedia.org/wiki/Error_threshold_(evolution)

    Stochastic corrector model (Szathmáry & Maynard Smith, 1995). In this proposed solution, a number of primitive molecules of say, two different types, are associated with each other in some way, perhaps by a capsule or "cell wall".

  8. Cellular model - Wikipedia

    en.wikipedia.org/wiki/Cellular_model

    The eukaryotic cell cycle is very complex and is one of the most studied topics, since its misregulation leads to cancers. It is possibly a good example of a mathematical model as it deals with simple calculus but gives valid results. Two research groups [1] [2] have produced several models of the cell cycle simulating several organisms. They ...

  9. Novak–Tyson model - Wikipedia

    en.wikipedia.org/wiki/Novak–Tyson_model

    The Novak–Tyson Model is a non-linear dynamics framework developed in the context of cell-cycle control by Bela Novak and John J. Tyson. It is a prevalent theoretical model that describes a hysteretic, bistable bifurcation of which many biological systems have been shown to express.