{"id":126,"date":"2024-03-03T08:58:06","date_gmt":"2024-03-03T08:58:06","guid":{"rendered":"https:\/\/pressbooks.justwrite.in\/interactive-biology-secondary\/?post_type=chapter&p=126"},"modified":"2024-11-30T05:34:58","modified_gmt":"2024-11-30T05:34:58","slug":"1-4-animal-cell","status":"publish","type":"chapter","link":"https:\/\/pressbooks.justwrite.in\/interactive-biology-secondary\/chapter\/1-4-animal-cell\/","title":{"raw":"1.4.Animal cell","rendered":"1.4.Animal cell"},"content":{"raw":"Animal cells are the fundamental units of animal tissues and organs. <\/span>\r\n\r\nThey are eukaryotic cells and therefore have membrane-bound organelles suspended in the cytoplasm enveloped by a[pb_glossary id=\"170\"] plasma membrane<\/strong>[\/pb_glossary].<\/span>\r\n\r\nAnimal cells have [pb_glossary id=\"171\"]centrosomes<\/strong> [\/pb_glossary](or a pair of centrioles), and [pb_glossary id=\"172\"]lysosomes<\/strong>[\/pb_glossary] which the\u00a0 plant cells do not possess.<\/span>\r\n\r\nA typical structure of an animal cell includes Organelles ( We will discuss about this in chapter 1.5) , <\/span>cytoplasmic structures, Cytosol <\/span>and Cell membrane .<\/span>\r\n\r\nThe cell organelles\u00a0 like Centrosomes<\/strong> and lysosomes<\/strong> are found only\u00a0 in animal cells, but do not exist within plant cells<\/span>\r\n

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\"Animal cell \"<\/a>\u00a0by\u00a0<\/span>OpenStax,via Wiki media commons\u00a0<\/span><\/a><\/a><\/a>is licensed under\u00a0<\/span>CC BY 4.0<\/a><\/p>\r\n\r\n

Cell Membrane or the Plasma membrane<\/h1>\r\nThe cell membrane of an animal cell is a lipid bilayer which is embedded with other molecules like proteins, cholesterol and with some carbohydrates attached.\r\n\r\nIt separates the interior of the cell from the outside environment.\r\n\r\n\u00a0The cell membrane\u00a0 is semipermeable. The cell membrane regulates the transport of materials entering and exiting the cell.<\/span>\r\n\r\nThe plasma membrane as it is other wise called permits the entry of small non polar molecules with ease, while large , polar molecules requires the help of transporters like membrane proteins .\u00a0<\/span>\r\n\r\nThe cholesterol embedded in the membrane\u00a0 provides structural integrity and support. <\/span>Furthermore, the presence of cholesterol makes the membrane\u00a0 fluid rather than rigid, and renders them the capability of movement.<\/span>\r\n\r\n\"This\r\n

\"Cell membrane \"<\/a>\u00a0by\u00a0<\/span>Openstax<\/a><\/a><\/a>\u00a0is licensed under\u00a0<\/span>CC BY 4.0<\/a><\/p>\r\nThe membrane proteins are of two categories namely Integral membrane proteins<\/strong> and peripheral membrane proteins<\/strong>\r\n\r\nIntegral membrane proteins\u00a0<\/strong>\r\n\r\nThese are otherwise called as Intrinsic proteins . These are proteins that are permanently attached to the cell membrane.<\/span>\r\n\r\nTheir functions include :\u00a0 channeling or transport molecules across the membrane , cell receptors, cell adhesion\r\n\r\nThey are further classified as\r\n

    \r\n \t
  1. Transmembrane proteins : these span the entire plasma membrane and are found in all types of biological membranes<\/li>\r\n \t
  2. Integral monotypic proteins : these are permanently attached to the membrane from only one side.<\/li>\r\n<\/ol>\r\nPeripheral membrane proteins\u00a0<\/strong>\r\n\r\n\u00a0These are proteins that are only temporarily associated with the membrane. <\/span>\r\n\r\nThey can be easily removed,<\/span>\r\n\r\nPeripheral proteins can also be attached to integral membrane proteins or they can be stick to the lipid bilayer.<\/span>\r\n\r\nThey are mostly hydrophilic.\r\n\r\nTheir functions include cell signaling, they are often associated with ion channels and transmembrane receptors.\r\n

    The Fluid Mosaic Model\u00a0<\/strong><\/h1>\r\nThis model about membrane structure was proposed by S.J.Singe and G.L.Nicolson in the year 1972.\r\n\r\nThis model is now widely accepted .\r\n\r\nThe postulates of this model are:\r\n