front 1 Which statement about membranes is true? a. Most plasma membranes contain more than 70% proteins. b. Sterol lipids are common in bacterial plasma membranes. c. Sterol lipids are common in human cell plasma membranes. d. Sterol lipids are common in plant cell plasma membranes. e. The plasma membranes of all cell types within a particular organism have basically the same lipid and protein composition. | back 1 c |
front 2 The fluidity of the lipid side chains in the interior of a bilayer is generally increased by: a. a decrease in temperature. d. an increase in the percentage of phosphatidylethanolamine. e. the binding of water to the fatty acyl side chains. | back 2 c |
front 3 The fluidity of a lipid bilayer will be increased by: a. decreasing the number of unsaturated fatty acids. b. decreasing the temperature. d. increasing the temperature. e. substituting 18:0 (stearic acid) in place of 18:2 (linoleic acid) | back 3 d |
front 4 Which statement is true regarding the regulation of β oxidation?
| back 4 b |
front 5 Fatty acids are activated to acyl-CoAs and the acyl group is further transferred to carnitine because:
| back 5 a |
front 6 In β oxidation, which cofactor is required for the conversion of a β-ketoacyl-CoA to an acyl-CoA and an acetyl-CoA molecule?
| back 6 d |
front 7 In β oxidation, which cofactor is required for the conversion of a β-hydroxyacyl-CoA to a β-ketoacyl-CoA? a. NAD+ b. FAD c. H2O d. CoA-SH | back 7 a |
front 8 In β oxidation, which cofactor is required for the conversion of a trans-Δ2-enoyl-CoA to a β-hydroxyacyl-CoA? a. NAD+ b. FAD c. H2O d. CoA-SH | back 8 c |
front 9 What products from the oxidation of odd-numbered fatty acids enter the citric acid cycle? a. acetyl-CoA and citrate d. acetyl-CoA and succinyl-CoA | back 9 d |
front 10 If the 16-carbon saturated fatty acid palmitate is oxidized completely to carbon dioxide and water (via the β-oxidation pathway and the citric acid cycle), and all of the energy-conserving products are used to drive ATP synthesis in the mitochondrion, the net yield of ATP per molecule of palmitate is: a. 3. b. 10. e. 1,000. | back 10 d |
front 11 Saturated fatty acids are degraded by the stepwise reactions of β oxidation, producing acetyl-CoA. Under aerobic conditions, how many ATP molecules would be produced as a consequence of removal of each acetyl-CoA? a. two b. three c. four d. five e. six | back 11 e |
front 12 Ketone bodies are formed in the liver and transported to the extrahepatic tissues mainly as: a. acetoacetyl-CoA. d. β-hydroxybutyryl-CoA. e. lactic acid. | back 12 c |
front 13 Which statement is false regarding ketone bodies? | back 13 d |
front 14 Which statement regarding ketone bodies is false?
| back 14 b |
front 15 In which cellular compartment are ketone bodies synthesized? a. the cytosol | back 15 b |
front 16 Which pathway is likely to be affected by a deficiency in carnitine? a. α oxidation b. β oxidation c. uptake of fatty acids from the bloodstream d. All of the answers are correct. | back 16 b |
front 17 Which statement is true regarding the regulation of β oxidation? a. AMPK activates acetyl-CoA carboxylase, which leads to the inhibition of β oxidation. b. A buildup in the levels of acetyl-CoA inhibits the thiolysis reaction in β oxidation. c. High levels of NADP+ activate β-hydroxyacyl-CoA dehydrogenase. d. Malonyl-CoA inhibits carnitine acyltransferase 2, which leads to the inhibition of β oxidation. e. β oxidation is enhanced in erythrocytes during starvation. | back 17 b |
front 18 Transport of fatty acids from the cytoplasm to the mitochondrial matrix requires: a. ATP, carnitine, and coenzyme A. | back 18 a |
front 19 The rate-limiting step in fatty acid synthesis is: a. condensation of acetyl-CoA and malonyl-CoA. | back 19 d |
front 20 Which statement is false concerning acetyl-CoA carboxylase? a. It catalyzes the rate-limiting step in fatty acid
synthesis. | back 20 d |
front 21 What cofactor is required for acetyl-CoA carboxylase activity? a. NADPH b. thiamine pyrophosphate c. lipoamide d. biotin | back 21 d |
front 22 Synthesis of malonyl-CoA from acetyl-CoA is MOST similar to what other reaction? a. conversion of malate into fumarate d. conversion of glutamate into α-ketoglutarate | back 22 e |
front 23 Which statement applies to synthesis of malonyl-CoA? a. It is synthesized from acetyl-CoA and bicarbonate. | back 23 e |
front 24 What cofactor is required for acetyl-CoA carboxylase activity? a. NADPH b. thiamine pyrophosphate c. lipoamide d. biotin | back 24 d |
front 25 Which statement is false regarding acyl carrier protein (ACP)?
| back 25 d |
front 26 What statement is false regarding the regulation of HMG-CoA reductase?
| back 26 b |
front 27 The rate-limiting step in fatty acid synthesis is: a. condensation of acetyl-CoA and malonyl-CoA. | back 27 d |
front 28 In comparing fatty acid biosynthesis with β oxidation of fatty acids, which statement is incorrect? a. A thioester derivative of crotonic acid (trans-2-butenoic acid) is an intermediate in the synthetic path, and in the degradative path. b. A thioester derivative of D-β-hydroxybutyrate is an intermediate in the synthetic path, not in the degradative path. c. Fatty acid biosynthesis uses NADPH exclusively, whereas β oxidation uses NAD+ exclusively. d. Fatty acid degradation is catalyzed by cytosolic enzymes; fatty acid synthesis by mitochondrial enzymes. | back 28 d |
front 29 How many phosphoanhydride bonds (net) are consumed in the conversion of mevalonate into the activated isoprene compound dimethylallyl pyrophosphate? a. zero b. one c. two d. three e. four | back 29 d |
front 30 Which compound is NOT an intermediate in the synthesis of lanosterol from acetyl-CoA? a. isopentenyl pyrophosphate b. malonyl-CoA c. mevalonate d. squalene | back 30 b |
front 31 Cholesterol is synthesized from: a. acetyl-CoA. b. choline. c. lipoic acid. d. malate. e. oxalate. | back 31 a |
front 32 A 30-carbon precursor of the steroid nucleus is: a. farnesyl pyrophosphate. b. geranyl pyrophosphate. c. isopentenyl pyrophosphate. d. lysolecithin. e. squalene. | back 32 e |
front 33 Which statement about cholesterol synthesis is true?
| back 33 c |
front 34 Which statement is a step in the uptake of cholesterol from the bloodstream into cells? a. LDL containing ApoB-100 is recognized by the LDL receptor. b. LDL bound to the LDL receptor leads to endocytosis of the complex. c. The cholesteryl esters in the LDL are hydrolyzed to release free cholesterol. d. The ApoB-100 protein is degraded. e. All of the above are steps in the uptake of cholesterol. | back 34 e |
front 35 Which statement about the regulation of cholesterol synthesis is NOT true? a. Cholesterol acquired in the diet has essentially no effect on cholesterol synthesis in the liver. b. Failure to regulate cholesterol synthesis predisposes humans to atherosclerosis. c. High intracellular cholesterol stimulates the formation of cholesteryl esters. d. Insulin stimulates HMG-CoA reductase. e. Some metabolite or derivative of cholesterol inhibits HMG-CoA reductase. | back 35 a |
front 36 Which apolipoprotein is found in chylomicrons but not in other lipoproteins? a. ApoB-48 b. ApoB-100 c. ApoC-II d. ApoC-III e. ApoE | back 36 a |
front 37 Reverse cholesterol transport is primarily associated with which lipoprotein? a. chylomicrons b. VLDL c. IDL d. LDL e. HDL | back 37 e |
front 38 Conversion of VLDL into LDL is associated with what changes? a. depletion of cholesteryl esters b. an increase in particle diameter c. an increase in the protein-lipid ratio d. ApoE-mediated receptor interactions | back 38 c |
front 39 Which apolipoprotein binds to the LDL receptor? a. ApoB-100 b. ApoC-I c. ApoC-II d. ApoD e. ApoE | back 39 a |
front 40 Which lipoproteins do NOT originate from the liver? a. chylomicrons and VLDL b. VLDL and HDL c. LDL and HDL d. chylomicrons e. VLDL and LDL | back 40 d |
front 41 Lipoprotein particles in human blood do NOT contain: a. an apolipoprotein B isoform. b. cholesterol. c. cholesteryl esters. d. phosphatidylcholine. e. triglycerides. | back 41 d |
front 42 What statement is false regarding the regulation of HMG-CoA reductase?
| back 42 b |
front 43 Which statement about membranes is true?
| back 43 c |
front 44 Which statement about the composition of biological membranes is false?
| back 44 a |
front 45 Which statement about the composition of membranes is true? a. All biological membranes contain cholesterol. | back 45 c |
front 46 Which lipid compound is NOT at least partially made from the condensation of isoprene units? a. sterols b. limonene c. beta-carotene d. vitamin E e. phosphatidylinositol | back 46 e |
front 47 Which eicosanoids contains a five-carbon ring as part of its structure? a. thromboxanes b. prostaglandins c. lipoxins d. leukotrienes e. arachidonates | back 47 b |
front 48 Fatty acids are a component of: a. carotenes. b. cerebrosides. c. sterols. d. vitamin D. e. vitamin K. | back 48 b |
front 49 Biological waxes are all: a. triesters of glycerol and palmitic acid. b. esters of single fatty acids with long-chain alcohols. c. triesters of glycerol and three long-chain saturated fatty acids. d. sphingolipids. e. None of the answers is correct. | back 49 b |
front 50 Which statement is true of lipids? a. Many contain fatty acids involved in ester or amide linkages. b. Most are classified as polymers. c. Testosterone is an important sphingolipid found in myelin. d. They are more soluble in water than in chloroform. e. They play only passive roles as energy-storage molecules. | back 50 a |
front 51 Fatty acids are a component of: a. carotenes. b. cerebrosides. c. sterols. d. vitamin D. e. vitamin K. | back 51 b |
front 52 Which statement is true about fatty acids? a. Fatty acids with longer chains have lower melting points. b. Fatty acids with longer chains have higher solubility in water. c. Fatty acids with more double bonds have higher melting points. d. Fatty acids with longer chains have higher melting points and lower solubility in water. e. None of the statements is true. | back 52 d |
front 53 What is the abbreviated nomenclature for a 14-carbon omega-3 fatty acid that contains no other double bonds? a. 14:1 (Δ11) b. 17:1 (Δ14) c. 14:1 (Δ3) d. 13:1 (Δ11) e. 14:0 (Δ11) | back 53 a |
front 54 Which type of chemical linkage is used to join fatty acids to glycerol? a. ether linkage b. peptide bond c. ester linkage d. double bond e. peroxide bond | back 54 c |
front 55 Commercial vegetable oils can be converted from liquid forms to solid forms and have their shelf lives increased due to which process? a. partial desaturation b. unsaturation c. partial hydrogenation d. hydrolysis e. complete esterification | back 55 c |
front 56 Waxes are BEST described as: a. esters of glycerol and three fatty acids. b. esters of one long-chain fatty acid and one long-chain alcohol. c. polyunsaturated long-chain fatty acids. d. esters of two long-chain fatty acids. e. ethers of glycerol and short-chain alcohols | back 56 b |
front 57 In neutral fats, three fatty acids are generally linked to a _____ backbone. a. glycogen b. glycerol c. sphingosine d. glucose e. phosphoglycerol | back 57 b |
front 58 Which term BEST describes the polarity of membrane lipids? a. ambidextrous b. completely nonpolar c. amphipathic d. completely polar e. amphibolic | back 58 c |
front 59 Which statement describes a distinct difference between membrane lipids in archaea and membrane lipids in eukaryotes? a. Archaeal membrane lipids have alkyl acids that are ether-linked to glycerol at both ends. b. Eukaryotic membrane lipids consist of glycerol that is ester-linked to three fatty acids. c. Only eukaryotic membrane lipids are amphipathic. d. Archaeal membrane lipids always contain sphingosine. e. Eukaryotic membrane lipids always have a phosphate group attached to glycerol. | back 59 a |
front 60 Which compound is NOT a type of membrane lipid? a. sphingolipid b. glycerophospholipid c. sulfolipid d. sterol e. triacylglycerol | back 60 e |
front 61 Platelet-activating factor is much more water soluble than most other glycerophospholipids due to which feature? a. its ether-linked alkyl chain at the C-1 of glycerol b. its ester-linked acetic acid at the C-2 of glycerol c. its ethanolamine head group d. its lack of any long alkyl chains linked to glycerol e. the presence of sphingosine, rather than glycerol, as a lipid backbone | back 61 b |
front 62 Fatty acids are attached to sphingosine by what type of chemical linkage? a. ether b. amide c. ester d. peroxide e. alkyl | back 62 b |