Biol309 Question Bank Membrane StructureMultiple Choice1. The fluidity of a membrane will decrease as a result of which one of the following changes?A. increasing the average length of the fatty acidsB. increasing the number of double bonds in the fatty acidsC. decreasing the amount of cholesterol in the membraneD. increasing the temperature of the membrane2. Which one of the following statements correctly describes membrane structure?A. Most membrane constituents are fixed in a specific location in the membrane.B. The hydrophobic region of the membrane is located along the exposed outer surface.C. Membranes consist of a ‘sandwich’ of lipids on the outside and protein on the inside.D. Phospholipids are arranged with the fatty acids facing toward the center.3. Which one of the following statements best describes phospholipid molecules?A. They contain two fatty acids with an ester linkage to a glycerol residue.B. Phospholipids of membranes always contain unsaturated fatty acids. C. Phospholipids contain three fatty acid residues and a hydrophobic head group.D. Along with triglycerides, phospholipids serve as important energy sources.4. Which one of the following molecules is least likely to serve as a phospholipid’s head group? A. choline C. riboseB. serine D. ethanolamine5. Which of these functions might be expected for a membrane protein?A. serving as membrane receptors.B. transport of substances across the membrane.C. providing structure and support to the membrane.D. All of the above are functions of membrane proteins.6. The function of cholesterol would be best described as:A. serving as hormone receptors.B. modifying the fluidity of membranes.C. facilitating the transport of lipids through the membrane.D. causing arteriosclerosis and heart attacks7. Considering membranes with phospholipids with these different average length fatty acids, which one would be expected to display the highest fluidity?A. 8 B.10 C.12 D.148. Considering membranes with phospholipids with fatty acids with these different average number of double bonds, which one would be expected to display the highest fluidity?A. 0 B.1 C.2 D.3Biol 309 Question Bank Membrane structure Page 19. Molecules of the ____________ play the most important role in direct adhesion between cells.A. Cell membrane C. Cell cortexB. Extracellular matrix D. Cell wall10. When dispersed into water, will each one of the following molecules form a1) bilayer 2) micelle 3) insoluble droplet 4) or dissolveExplain your answers.A. triacylglycerolB. acetoneC. sodium dodecyl sulfateD. palmitic acid11. Longer fatty acids make membranes less fluid because:A. the long chains tend to get interwined and tangled.B. this allows greater hydrogen-bonding between the methyl groups.C. longer fatty acids bind rather tenaciously to membrane proteins.D. there are more van derWaals interactions between the chains.12. More double-bonds in fatty acids make membranes more fluid because:A. fatty acids with lots of double bonds strongly repel each other.B. the fatty acids cannot not pack together as tightly.C. double bonds prevent cholesterol from entering the membrane.D. the phospholipids tend to flip-flop across the membrane more quickly.13. Why do glycolipids exist almost exclusively on the exterior side, but not the cytoplasmic side, of the cell membrane?A. The inner layer of the membrane is not thick enough to accommodate carbohydratesB. Flippases move the glycolipids to this side of the membrane.C. Carbohydrates are added only to lipids on the lumen side of the ER and golgimembranes.D. Carbohydrates are removed from the cytoplasmic side by glycosylase enzymes.14. Does each of the following statements correctly describe the:1) cell ‘cortex’ 2) ‘extracellular matrix’ 3) or bothA. This is the location of structural proteins that reinforce the cell membrane.B. This region is rich in carbohydrate-containing macromolecules.C. This region is the site of many enzymatic processes.D. This layer provides anchor points for membrane proteins.E. Molecules in this layer play an important role in cell-to-cell recognition.F. This layer influences the shape of the cell.G. This layer becomes hydrated and lubricates cell movement.Biol 309 Question Bank Membrane structure Page 215. Which of the following membrane protein structures…1) single pass alpha helix 2) 5x multipass alpha helix 3) 18-strand beta-sheet…is most-likely to be found in a(n):A. aqueous ion-channel B) anchor protein C) membrane receptorExplain your answers.16. A "tight junction":A. is a special type membrane phospholipid molecule.B. is the layer of protein and carbohydrate found between all cells.C. restricts membrane proteins in the membrane to distinct domains.D. resembles a small pore interconnecting two adjacent cells.E. separates a cell from the external environment.17. The experimental procedure known as "FRAP" can be used to demonstrate that: A. cell membranes are composed of a bilayer of phospholipid molecules.B. lipid molecules can "flip-flop" across the two sides of the lipid bilayer.C. lipid and protein molecules move within a lipid bilayer.D. membrane proteins transport specific molecules across the cell membrane.True and False1. The membrane of internal organelles consists of single layers (not a bilayer) of phospholipids.2. The structures of most membrane proteins are now well known.3. All membrane lipids are phospholipids.4. In general, there is great diversity of oligosaccharide structures among glycoproteins and glycolipids. 5. Increasing the cholesterol content of a lipid bilayer will decrease the fluidity of the membrane.6. Most phospholipid synthesis occurs on the cytoplasmic side of the ER membrane.7. After fusion with the cell membrane, the lumen side of a vesicle membrane will lie on the cytoplasmic side of the cell membrane.8. Weak detergents can be used to free proteins from membranes, but strong detergents will completely denature the proteins.Biol 309 Question Bank Membrane structure Page 3Fill in, etc1. Complete the following sentences using the word ‘hydrophobic’, ‘hydrophilic’ or ‘amphiphatic’.The most amino acids of the transmembrane alpha-helix would be expected to have __________________ side-chains. An ion passing through a mutipass transmembrane protein would interact predominantly with ________________ amino acids. Membrane proteins can be isolated from membranes with the use of __________________