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  2. Biological organisation - Wikipedia

    en.wikipedia.org/wiki/Biological_organisation

    Each level in the hierarchy represents an increase in organisational complexity, with each "object" being primarily composed of the previous level's basic unit. [2] The basic principle behind the organisation is the concept of emergence —the properties and functions found at a hierarchical level are not present and irrelevant at the lower levels.

  3. Organelle - Wikipedia

    en.wikipedia.org/wiki/Organelle

    The name organelle comes from the idea that these structures are parts of cells, as organs are to the body, hence organelle, the suffix -elle being a diminutive. Organelles are either separately enclosed within their own lipid bilayers (also called membrane-bounded organelles) or are spatially distinct functional units without a surrounding ...

  4. Organ (biology) - Wikipedia

    en.wikipedia.org/wiki/Organ_(biology)

    The organ level of organisation in animals can be first detected in flatworms and the more derived phyla, i.e. the bilaterians. The less-advanced taxa (i.e. Placozoa, Porifera, Ctenophora and Cnidaria) do not show unification of their tissues into organs. More complex animals are composed of different organs, which have evolved over time.

  5. Nuclear organization - Wikipedia

    en.wikipedia.org/wiki/Nuclear_Organization

    Examples of different levels of nuclear architecture. Nuclear organization refers to the spatial organization and dynamics of chromatin within a cell nucleus during interphase. There are many different levels and scales of nuclear organisation. At the smallest scale, DNA is packaged into units called nucleosomes, which compacts DNA about 7-fold.

  6. Biological system - Wikipedia

    en.wikipedia.org/wiki/Biological_system

    Biological organization spans several scales and are determined based different structures depending on what the system is. [1] Examples of biological systems at the macro scale are populations of organisms. On the organ and tissue scale in mammals and other animals, examples include the circulatory system, the respiratory system, and the ...

  7. Bacterial cell structure - Wikipedia

    en.wikipedia.org/wiki/Bacterial_cell_structure

    Bacterial microcompartments are widespread, organelle-like structures that are made of a protein shell that surrounds and encloses various enzymes. provide a further level of organization; they are compartments within bacteria that are surrounded by polyhedral protein shells, rather than by lipid membranes. These "polyhedral organelles ...

  8. Tissue (biology) - Wikipedia

    en.wikipedia.org/wiki/Tissue_(biology)

    In biology, tissue is an assembly of similar cells and their extracellular matrix from the same embryonic origin that together carry out a specific function. [1] [2] Tissues occupy a biological organizational level between cells and a complete organ.

  9. Cell theory - Wikipedia

    en.wikipedia.org/wiki/Cell_theory

    Besides stating “the cell is the fundamental element of organization”, Dutrochet claimed that cells were also a physiological unit. [ 7 ] In 1804, Karl Rudolphi and J. H. F. Link were awarded the prize for "solving the problem of the nature of cells", meaning they were the first to prove that cells had independent cell walls by the ...