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  2. DNA - Wikipedia

    en.wikipedia.org/wiki/DNA

    The A form occurs under non-physiological conditions in partly dehydrated samples of DNA, while in the cell it may be produced in hybrid pairings of DNA and RNA strands, and in enzyme-DNA complexes. [ 54 ] [ 55 ] Segments of DNA where the bases have been chemically modified by methylation may undergo a larger change in conformation and adopt ...

  3. Cell wall - Wikipedia

    en.wikipedia.org/wiki/Cell_wall

    A cell wall is a structural layer that surrounds some cell types, found immediately outside the cell membrane.It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, and functions as a selective barrier. [1]

  4. Bacterial cell structure - Wikipedia

    en.wikipedia.org/wiki/Bacterial_cell_structure

    Therefore, a typical fully grown 1-liter culture of Escherichia coli (at an optical density of 1.0, corresponding to c. 10 9 cells/ml) yields about 1 g wet cell mass. [2] Small size is extremely important because it allows for a large surface area-to-volume ratio which allows for rapid uptake and intracellular distribution of nutrients and ...

  5. Nucleic acid structure - Wikipedia

    en.wikipedia.org/wiki/Nucleic_acid_structure

    A-DNA, is a form of the DNA duplex observed under dehydrating conditions. It is shorter and wider than B-DNA. RNA adopts this double helical form, and RNA-DNA duplexes are mostly A-form, but B-form RNA-DNA duplexes have been observed. [14] In localized single strand dinucleotide contexts, RNA can also adopt the B-form without pairing to DNA. [15]

  6. Bacteria - Wikipedia

    en.wikipedia.org/wiki/Bacteria

    The cell wall of bacteria is also distinct from that of achaea, which do not contain peptidoglycan. The cell wall is essential to the survival of many bacteria, and the antibiotic penicillin (produced by a fungus called Penicillium) is able to kill bacteria by inhibiting a step in the synthesis of peptidoglycan. [76]

  7. Nucleic acid tertiary structure - Wikipedia

    en.wikipedia.org/.../Nucleic_acid_tertiary_structure

    The double helix is the dominant tertiary structure for biological DNA, and is also a possible structure for RNA. Three DNA conformations are believed to be found in nature, A-DNA, B-DNA, and Z-DNA. The "B" form described by James D. Watson and Francis Crick is believed to predominate in cells. [2]

  8. Chromosome - Wikipedia

    en.wikipedia.org/wiki/Chromosome

    This is an accepted version of this page This is the accepted version, checked on 12 January 2025. There are template/file changes awaiting review. DNA molecule containing genetic material of a cell This article is about the DNA molecule. For the genetic algorithm, see Chromosome (genetic algorithm). Chromosome (10 7 - 10 10 bp) DNA Gene (10 3 - 10 6 bp) Function A chromosome and its packaged ...

  9. Cell nucleus - Wikipedia

    en.wikipedia.org/wiki/Cell_nucleus

    The cell nucleus (from Latin nucleus or nuculeus 'kernel, seed'; pl.: nuclei) is a membrane-bound organelle found in eukaryotic cells.Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, have no nuclei, and a few others including osteoclasts have many.