Q) Describe the roles of three components of plasma membrane
Main points | |
Key idea: | Functions of cholesterol |
1) Regulates fluidity of membr · When temp rises, mol decrease fluidity by interacting w hydrocarbon chains of phospholipids, to prevent them fr moving too far fr each other. · When temp decreases, mol increase fluidity by disrupting close packing of phospholipids, to prevent membr fr solidifying 2) Provides mechanical stability to membr so it does not break easily 3) Important component of myelin sheath · Reduces uncontrolled leakage of ions a/x membr of neurones, needed for efficient nerve transmission | |
Key idea: | Functions of glycoproteins and glycolipids |
· Both found only on ext surf of cell membr (ref to carbo component, glycocalyx) 1) Cell to cell recognition and adhesion (e.g. aid wbc to detect + destroy pathogens) 2) Some glycoproteins serve as receptors - bind to specific signal mol (e.g. hormone), activate signal transduction pathways, result cellular responses 3) Stabilizes membr struc - orientation of carbo chains toward ext aq environment + ref to H bonds b/w the carbo chains + water mol | |
Comments: (i) Visualize the answer with the aid of a labelled cross section of the cell membrane (ii) Verbalize the answer + write down the main points w/o referring to the answer (use abbreviations) (iii) Read again within the next 24h & once more within 72h (do not spend more than 10min) (iv) Each specific role is worth 1 mark | |
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