The Plasma Membrane

Understanding

• The plasma membrane, found in various cell structures, is thin and difficult to see under a microscope.
• It contains the nucleus within a double plasma membrane, also known as the nuclear envelope.
• The plasma membrane consists of a double layer of phospholipid molecules with large protein molecules embedded.
• Each phospholipid molecule has a head that attracts water (hydrophilic) and a tail that repels water (hydrophobic).
• The double layer is impermeable to water-soluble substances like glucose, amino acids, salts, and nucleic acids, requiring transport by carrier proteins.
• The membrane is described as "fluid" due to its fluid nature.
• Water-soluble substances are transported into and out of the cell through diffusion, osmosis, and active transport.