Plasma Membrane  Responsible for homeostasis

Plasma membrane Thin, flexible boundary between a cell and its environment. Allows nutrients in and allows waste to leave cell Plasma membranes have Selective permeability: allows some substances to pass through while keeping others out. A cell membrane is called a fluid mosaic because it behaves more like a liquid than a solid.

Cell Membrane The cell membrane is selectively permeable which means some substances can cross and others cannot cross. Cell membranes are made of primarily lipids and proteins. Cell membranes are made of a lipid bi-layer. A cell membrane is called a fluid mosaic because it behaves more like a liquid than a solid. It is flexible and provides an effective barrier and transport function.

Structure of Plasma Membrane Cell membranes are made of a lipid bi-layer. (double layer) A single phospholipid molecule has two different ends: a head and a tail. The head end contains a phosphate group and is hydrophilic. This means that it likes or is attracted to water molecules. Phosphate group makes the head polar and is attracted to water ( water also polar)

Structure of Plasma Membrane The tail end is made up of two strings of hydrogen and carbon atoms called fatty acid chains. The tail is hydrophobic or do not like to mingle with water molecules 2 fatty acid tails are nonpolar and are repelled by water

Inside Plasma Membrane Cholesterol, proteins, and carbohydrates move among the phospholipids. Proteins: transmit signals, anchor the cells Transport protein: tunnel for certain substances to enter and leave cell( aid movement of substances) Cholesterol: helps the fatty acid tails from sticking together. ( structure) Carbohydrate chain: define cells characteristics and help cells identify chemical signals(recognition marker) Enzymes: biochemical reactions within the cell

Cell Membrane Carbohydrate Chain: Recognition marker( self or non self Transport protein: aid the movement of substances Enzymes: biochemical reactions within the cell Receptor proteins: bind certain substances

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