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  2. Vacuole - Wikipedia

    en.wikipedia.org/wiki/Vacuole

    Animal cell structure. A vacuole (/ ˈvækjuːoʊl /) is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. [1][2] Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution, though in ...

  3. Contractile vacuole - Wikipedia

    en.wikipedia.org/wiki/Contractile_vacuole

    The contractile vacuole acts as part of a protective mechanism that prevents the cell from absorbing too much water and possibly lysing (rupturing) through excessive internal pressure. The contractile vacuole, as its name suggests, expels water out of the cell by contracting. The growth (water gathering) and contraction (water expulsion) of the ...

  4. Endomembrane system - Wikipedia

    en.wikipedia.org/wiki/Endomembrane_system

    The endomembrane system is composed of the different membranes (endomembranes) that are suspended in the cytoplasm within a eukaryotic cell. These membranes divide the cell into functional and structural compartments, or organelles. In eukaryotes the organelles of the endomembrane system include: the nuclear membrane, the endoplasmic reticulum ...

  5. Cell (biology) - Wikipedia

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

    The cell is the basic structural and functional unit of all forms of life. Every cell consists of cytoplasm enclosed within a membrane; many cells contain organelles, each with a specific function. The term comes from the Latin word cellula meaning 'small room'. Most cells are only visible under a microscope.

  6. Tissue (biology) - Wikipedia

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

    The dense protoplasm of meristematic cells contains very few vacuoles. Normally the meristematic cells are oval, polygonal , or rectangular in shape. Meristematic tissue cells have a large nucleus with small or no vacuoles because they have no need to store anything, as opposed to their function of multiplying and increasing the girth and ...

  7. Endocytosis - Wikipedia

    en.wikipedia.org/wiki/Endocytosis

    Endocytosis. Endocytosis is a cellular process in which substances are brought into the cell. The material to be internalized is surrounded by an area of cell membrane, which then buds off inside the cell to form a vesicle containing the ingested materials. Endocytosis includes pinocytosis (cell drinking) and phagocytosis (cell eating).

  8. Vesicle (biology and chemistry) - Wikipedia

    en.wikipedia.org/wiki/Vesicle_(biology_and...

    Vesicle (biology and chemistry) Scheme of a liposome formed by phospholipids in an aqueous solution. In cell biology, a vesicle is a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer. Vesicles form naturally during the processes of secretion (exocytosis), uptake (endocytosis), and the transport of ...

  9. Guard cell - Wikipedia

    en.wikipedia.org/wiki/Guard_cell

    Guard cells are cells surrounding each stoma. They help to regulate the rate of transpiration by opening and closing the stomata. Light is the main trigger for the opening or closing. Each guard cell has a relatively thick and thinner cuticle on the pore-side and a thin one opposite it. As water enters the cell, the thin side bulges outward ...