DR . ONYESO
SENIOR LECTURER
DEPARTMENT OF HUMAN PHYSIOLOGY
RIVERS STATE UNIVERSITY
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, Lipids of cell membrane
• The Cell membrane consists primarily of
• phospholipids
– phospholipid bilayer hydrophilic
inside cell phosphate
lipid
hydrophobic
outside cell
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, The Fluidity of Membranes
• Phospholipids in the membrane are
• Fluid like (they can move easily)
Lateral movement Flip-flop
(~107 times per second) (~ once per month)
(a) Movement of phospholipids
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, Semi-permeable membrane
• Will allow passage through the membrane
• But need to control what gets in or out
– membrane is semi-permeable
sugar aa lipid H2 O salt NH3
So how does a semi-
permeable membrane work?
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