When.com Web Search

Search results

  1. Results From The WOW.Com Content Network
  2. Cell wall - Wikipedia

    en.wikipedia.org/wiki/Cell_wall

    A plant cell wall was first observed and named (simply as a "wall") by Robert Hooke in 1665. [3] However, "the dead excrusion product of the living protoplast" was forgotten, for almost three centuries, being the subject of scientific interest mainly as a resource for industrial processing or in relation to animal or human health.

  3. Regiomontanus' angle maximization problem - Wikipedia

    en.wikipedia.org/wiki/Regiomontanus'_angle...

    In mathematics, the Regiomontanus's angle maximization problem, is a famous optimization problem [1] posed by the 15th-century German mathematician Johannes Müller [2] (also known as Regiomontanus). The problem is as follows: The two dots at eye level are possible locations of the viewer's eye. A painting hangs from a wall.

  4. Secondary cell wall - Wikipedia

    en.wikipedia.org/wiki/Secondary_cell_wall

    Plant cell overview, showing secondary cell wall. The secondary cell wall has different ratios of constituents compared to the primary wall. An example of this is that secondary wall in wood contains polysaccharides called xylan, whereas the primary wall contains the polysaccharide xyloglucan. The cells fraction in secondary walls is also ...

  5. Cell mechanics - Wikipedia

    en.wikipedia.org/wiki/Cell_mechanics

    Cell mechanics is a sub-field of biophysics that focuses on the mechanical properties and behavior of living cells and how it relates to cell function. [1] It encompasses aspects of cell biophysics , biomechanics , soft matter physics and rheology , mechanobiology and cell biology .

  6. Plant cell - Wikipedia

    en.wikipedia.org/wiki/Plant_cell

    Structure of a plant cell. Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae.Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or ...

  7. Azimuth - Wikipedia

    en.wikipedia.org/wiki/Azimuth

    The azimuth is the angle formed between a reference direction (in this example north) and a line from the observer to a point of interest projected on the same plane as the reference direction orthogonal to the zenith. An azimuth (/ ˈ æ z ə m ə θ / ⓘ; from Arabic: اَلسُّمُوت, romanized: as-sumūt, lit.

  8. Wall stress relaxation - Wikipedia

    en.wikipedia.org/wiki/Wall_stress_relaxation

    It has been found that cell walls expand faster under acidic conditions, this is called acid growth. Treating living cells with acid induces acidification of the cell wall by activating an ATPase in the cell wall's plasma membrane. [1] In onion epidermal cells, which are used as models to study anisotropy in extension, extension is pH dependent ...

  9. Horizontal coordinate system - Wikipedia

    en.wikipedia.org/wiki/Horizontal_coordinate_system

    Azimuth is measured eastward from the north point (sometimes from the south point) of the horizon; altitude is the angle above the horizon. The horizontal coordinate system is a celestial coordinate system that uses the observer's local horizon as the fundamental plane to define two angles of a spherical coordinate system: altitude and azimuth.