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  2. 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]

  3. Cell membrane - Wikipedia

    en.wikipedia.org/wiki/Cell_membrane

    Illustration of a eukaryotic cell membrane Comparison of a eukaryotic vs. a prokaryotic cell membrane. The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of a cell from the outside environment (the extracellular space).

  4. Cell envelope - Wikipedia

    en.wikipedia.org/wiki/Cell_envelope

    The cell envelope comprises the inner cell membrane and the cell wall of a bacterium. In Gram-negative bacteria an outer membrane is also included. [ 1 ] This envelope is not present in the Mollicutes where the cell wall is absent.

  5. Cell (biology) - Wikipedia

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

    Enclosing the cell is the cell envelope, generally consisting of a plasma membrane covered by a cell wall which, for some bacteria, may be further covered by a third layer called a capsule. Though most prokaryotes have both a cell membrane and a cell wall, there are exceptions such as Mycoplasma (bacteria) and Thermoplasma (archaea) which only ...

  6. Bacterial cell structure - Wikipedia

    en.wikipedia.org/wiki/Bacterial_cell_structure

    The cell envelope is composed of the cell membrane and the cell wall. As in other organisms, the bacterial cell wall provides structural integrity to the cell. In prokaryotes , the primary function of the cell wall is to protect the cell from internal turgor pressure caused by the much higher concentrations of proteins and other molecules ...

  7. Gram-negative bacteria - Wikipedia

    en.wikipedia.org/wiki/Gram-negative_bacteria

    The outer membrane protects the bacteria from several antibiotics, dyes, and detergents that would normally damage either the inner membrane or the cell wall (made of peptidoglycan). The outer membrane provides these bacteria with resistance to lysozyme and penicillin.

  8. Lipid bilayer - Wikipedia

    en.wikipedia.org/wiki/Lipid_bilayer

    Prokaryotes have only one lipid bilayer - the cell membrane (also known as the plasma membrane). Many prokaryotes also have a cell wall, but the cell wall is composed of proteins or long chain carbohydrates, not lipids. In contrast, eukaryotes have a range of organelles including the nucleus, mitochondria, lysosomes and endoplasmic reticulum

  9. Biological membrane - Wikipedia

    en.wikipedia.org/wiki/Biological_membrane

    Cross-sectional view of the structures that can be formed by phospholipids in an aqueous solution. A biological membrane, biomembrane or cell membrane is a selectively permeable membrane that separates the interior of a cell from the external environment or creates intracellular compartments by serving as a boundary between one part of the cell and another.