different type of bio membranes

1. BIOMEMBRANES
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2. DEFINITION
 Biological membranes are thin, flexible
surfaces separating cells and cell
compartments from their environments
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3. ORGANELLES CONTAINING
MEMBERANE
Lysosomes Golgi bodies Mitochondria Nucleus
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4. FLUID MOSAIC MODEL
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5. COMPONENTS
Components of membrane are:
 Proteins
 lipids
 Carbohydrates
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6. PROTEINS
Two basic types of membrane proteins:
 Integral (Intrinsic) proteins
 Peripheral (extrinsic) proteins
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7. INTEGRAL (INTRINSIC)
PROTEINS
 They are embedded in hydrophobic core of
lipid bilayer
 For example : Transmembrane proteins
are exposed on both sides of the
membrane
FUNCTION:
 Anchorage
 Transport
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8. THREE GENERAL CLASSES OF
TRANSPORT SYSTEMS
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9. PERIPHERAL (EXTRINSIC)
PROTEINS
 Peripheral membrane proteins are proteins that adhere
outside the biological membrane
 These molecules attach to integral membrane
proteins, or penetrate the peripheral regions of the
lipid bilayer
FUNCTION:
 Cell-to-cell interaction
 Cell signaling
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10. MANY FUNCTIONS OF MEMBRANE
PROTEINS
Outside
Plasma
membrane
Inside
Transporter Cell surface
receptor
Enzyme
activity
Cell surface
identity marker
Attachment to the
cytoskeletonCell adhesion
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11. LIPIDS
 Lipids in membranes are Amphipathic
 Orientation of Amphipathic compounds (Lipids) in
aqueous solution is to prevent Hydrophobic region
coming into contact with water molecules
Major lipids in biological membranes are:
 Phospholipids
 Glycolipids
 Cholesterol
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12. PHOSPHOLIPIDS
Phospholipid is made up of:
 Two Non-polar (Hydrophobic) fatty acid
chains: Tails
 One polar (Hydrophilic) group: Head
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13.  Phospholipid molecules are
orientated to form:
 micelle
 lipid bilayer
 liposome
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14. PHOSPHOLIPID
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15. CHEMICAL NATURE OF
PHOSPHOLIPIDS
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16. GLYCOLIPIDS
 Glycolipids are lipids that form part of
the plasma membrane
 They have a short carbohydrate chain
covalently attached and this is exposed on the
outer surface of the cell
Function:
 Communicative or
cellular recognition
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17. CHOLESTEROL
 It is a steroid that is amphipathic in
nature
Function:
 Provide stability
 Maintain the fluidity
 Bilayer stronger
 Bilayer flexible
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18. CARBOHYDRATES
Carbohydrates covalently linked to proteins
(glycoproteins) or lipids (glycolipids) are
also a part of cell membranes
FUNCTION:
cell-cell recognition
 Basis for rejection of
foreign cells by
immune system
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19. GLYCOCALYX
 Entire surface of cell membrane contain
carbohydrate coat called glycocalyx
Function:
 Provide negative charge to the membrane
 Provide attachment between the cells
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20. FUNCTION OF CELL MEMBRANE
 The cell membrane is selectively
permeable to ions and organic
molecules and controls the movement
of substances in and out of cells
 The basic function of the cell
membrane is to protect
the cell from its surroundings
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21. IMPORTANT FEATURES
 Selective permeability
 Fluidity
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