Download Cell Membranes, Cell Biology - Biology - Quiz and more Exercises Cell Biology in PDF only on Docsity! 1. The table below refers to components of the cell surface membrane (plasma membrane) and to their roles in transporting substances across the membrane. Complete the table by inserting an appropriate word or words in the empty boxes. Component Phospholipid Carbohydrate side chain Protein Fatty acids, glycerol and phosphate monosaccharide/ named e.g. of a monosaccharide/ ref. to pentose/hexose; ester; glycosidic; Peptide Role in transportChemical bond between subunits Subunits Ref. to vesicle formation/cytosis/ chylomicrons/ref.to diffusion; Receptor Ref. to channels/pores allowing passage/ facilitated diffusion/ receptor/enzyme/ carrier/active transport; amino acids; [Total 6 marks] 2. Write an essay on the following topic. The structure and functions of cell surface membranes (Bio, Hbio) structure and function of cell surface membranes: Introduction could include: outline of fluid mosaic model - communication with external medium, barrier - controls exchange of material - fluid mosaic model: phospholipids and orientation - proteins, glycocalyx, channels - microvilli - passage through the membrane: diffusion, facilitated diffusion, Na/K - osmosis, active transport, ATPase - lipid soluble molecules, adrenaline polar molecules through pores, channels - Vesicles: cytosis - endocytosis, phagocytosis, pinocytosis - exocytosis, secretory vesicles others: glycosides as receptors, insulin- adhesion between cells - immunological response S = 13, B = 2,C = 2 [Total 15 marks] Docsity.com 3. (a) (i) A = glycerol 1 B = fatty acid (residue) 1 (ii) hydrolysis 1 (b) polar (molecules) / hydrophilic heads/eq & hydrophobic tails/eq 1 form a bilayer / bimolecular double layer [accept from clear diagram] 1 (polar/hydrophilic) heads outside / (non–polar/hydrophobic) tails inside 1 [6] 4. (a) A phospholipid ; B protein ; C glycoprotein ; 3 (b) act as a marker / antigen / recognition site ; other molecules combine with it / detecting similar / non-self cells ; OR reference to receptor / binding site ; other (specific) molecules / named e.g. / combine with it ; 2 [5] 5. (a) Phospholipid ; 1 (b) A Glycerol / propan 1,2,3 triol ; B Ester bond / ester linkage ; 2 (c) Insoluble in water / does not dissolve in water / non-polar ; 1 (d) (Fluid because) phospholipids move (around membrane) ; (Mosaic because) membrane contains proteins / glycoproteins (lying amongst phospholipids) / eq ; 2 [6] 6. (a) {Fatty acid / tails} are {hydrophobic / non-polar} ; (so orientate themselves) away from {water / polar environment} ; {Phosphate / heads} are {hydrophilic / polar} ; (so can) interact with {water / polar environment} ; 3 (b) Correct measurement ; [27 mm or 37 / 38 mm] Divide by magnification ; Correct conversion to µm ; [answer = 0.009 or 0.012 / 0.013] 3 (c) Carbohydrate: Cell recognition / cell adhesion / eq ; 1 Protein: Transport of molecules / eq OR receptor for hormone / eq OR enzymes ; 1 [8] Docsity.com
