Lipids
Answer: Biological membrane
1. The structure that separates the aqueous cytoplasm from the external environment and acts as a selectively permeable barrier.
Answer: Phospholipid bilayer
2. The basic structural arrangement formed when phospholipids assemble in water, with polar heads facing the aqueous environment and nonpolar tails directed inward.
Answer: Hydrophilic polar head
3. The water-attracting portion of a phospholipid that interacts with water.
Answer: Nonpolar fatty acid tails
4. The hydrophobic portions of phospholipids that form the interior of the membrane.
Answer: London dispersion forces
5. The forces that hold the nonpolar phospholipid tails in close proximity within the membrane.
Answer: Peripheral proteins
6. Membrane proteins that are embedded within the membrane but extend outward on only one side.
Answer: Integral proteins
7. Membrane proteins that extend through the entire phospholipid bilayer.
Answer: Simple diffusion
8. The movement of small molecules such as O₂ and CO₂ from an area of higher concentration to an area of lower concentration through the membrane.
Answer: Facilitated transport
9. The transport mechanism used by larger polar molecules and some ions that cannot efficiently cross the membrane by simple diffusion.
Answer: Active transport
10. The transport of substances against their concentration gradient that requires energy input.
Answer: Concentration gradient
11. The difference in concentration between two regions that determines the direction of passive movement.
Answer: Na⁺, K⁺, and Ca²⁺
12. The three ions specifically identified in the module as substances that may need to move against their concentration gradient.
Answer: Phospholipids
13. The major component of the cell membrane.
Answer: Lipids
14. Organic molecules whose identity is defined primarily by a physical property rather than by a particular functional group.
Answer: Hydrophobic
15. The property describing molecules that are not soluble in water and tend to associate into separate lipid phases.
Answer: Hexane
16. An organic solvent in which lipids are described as very soluble.
Answer: Triacylglycerols
17. The major fuel-storage lipids in the body.
Answer: Phospholipids, glycolipids, and cholesterol
18. The three lipid groups identified as crucial constituents of biological membranes.
Answer: Hydrolysis
19. The reaction in which triglycerols react with water to produce carboxylic acids and alcohol.
Answer: Saponification
20. The alkaline hydrolysis of lipids that produces fatty-acid salts or soap.
Answer: Hydrogenation
21. The reaction in which carbon-carbon double bonds of unsaturated fatty acids react with hydrogen to produce saturated fatty acids.
Answer: Halogenation
22. The addition reaction of halogens at the double bonds of unsaturated fatty acids.
Answer: Rancidity
23. The condition in which a fat or oil develops a disagreeable odor due to hydrolysis and/or oxidation.
Answer: Oxidative rancidity
24. The type of rancidity associated particularly with triacylglycerols containing unsaturated fatty acids.
Answer: Glycerol
25. The three-carbon molecule containing hydroxyl groups that forms the backbone of triacylglycerols.
Answer: Fatty acid
26. A naturally occurring monocarboxylic acid that usually has an unbranched carbon chain and an even number of carbon atoms.
Answer: Saturated fatty acid
27. A fatty acid whose carbon chain contains only single carbon-carbon bonds.
Answer: Monounsaturated fatty acid (MUFA)
28. A fatty acid containing exactly one carbon-carbon double bond.
Answer: Polyunsaturated fatty acid (PUFA)
29. A fatty acid containing two or more carbon-carbon double bonds.
Answer: Palmitic acid
30. The saturated C16 fatty acid synthesized first during fatty acid biosynthesis.
Answer: Delta (Δ) notation
31. The system that specifies the location of double bonds by using the Greek capital letter Δ and superscript numbers.
Answer: Omega (ω) notation
32. The system that identifies the position of the terminal double bond relative to the methyl end of a fatty acid.
Answer: Omega-3 fatty acid
33. An unsaturated fatty acid whose endmost double bond is three carbon atoms away from its methyl end.
Answer: Omega-6 fatty acid
34. An unsaturated fatty acid whose endmost double bond is six carbon atoms away from its methyl end.
Answer: Arachidonic acid
35. The PUFA with the structural notation 20:4(Δ5,8,11,14).
Answer: Short-chain fatty acids
36. Fatty acids containing 4 or 6 carbon atoms.
Answer: Medium-chain fatty acids
37. Fatty acids containing 8 or 10 carbon atoms.
Answer: Long-chain fatty acids
38. Fatty acids containing 12–26 carbon atoms.
Answer: Triacylglycerol
39. A lipid consisting of one glycerol molecule bonded to three fatty acid molecules.
Answer: Ester bond
40. The covalent linkage connecting fatty acids to glycerol in a triacylglycerol.
Answer: Condensation reaction
41. The type of reaction through which triacylglycerols are formed.
Answer: Fats
42. Triacylglycerol mixtures that are solid or semisolid at room temperature.
Answer: Oils
43. Triacylglycerol mixtures that are liquid at room temperature.
Answer: Saturated fatty acids
44. The fatty acids that generally predominate in fats and allow tighter packing.
Answer: Unsaturated fatty acids
45. The fatty acids that generally predominate in oils and have bends that prevent tight packing.
Answer: Adipocytes
46. Specialized cells in which triacylglycerols are primarily concentrated for energy storage.
Answer: Coconut oil
47. The notable oil exception that is highly saturated but remains liquid because it is rich in shorter-chain fatty acids.
Answer: Phospholipids
48. The most abundant type of membrane lipid.
Answer: Glycerophospholipids
49. Phospholipids built on a glycerol platform.
Answer: Sphingophospholipids
50. Phospholipids built on the C18 aminodialcohol sphingosine.
Answer: Phosphatidylcholine
51. A glycerophospholipid containing choline as its amino alcohol.
Answer: Phosphatidylethanolamine
52. A glycerophospholipid containing ethanolamine as its amino alcohol.
Answer: Phosphatidylserine
53. A glycerophospholipid containing serine as its amino alcohol.
Answer: Phosphatidyl group
54. The fatty acid, glycerol, and phosphate portions of a glycerophospholipid.
Answer: Sphingoglycolipids
55. Membrane lipids containing a fatty acid and carbohydrate component attached to sphingosine.
Answer: Cerebrosides
56. The simplest sphingoglycolipids containing a single monosaccharide, either glucose or galactose.
Answer: Gangliosides
57. More complex sphingoglycolipids containing a branched chain of up to seven monosaccharide residues.
Answer: Cholesterol
58. The specific membrane lipid that contains neither fatty acid residues nor glycerol or sphingosine as its platform molecule.
Answer: Steroid nucleus
59. The fused-ring system characteristic of steroids, consisting of three six-membered rings and one five-membered ring.
Answer: Bile acids
60. Cholesterol derivatives that function as emulsifying agents and facilitate intestinal absorption of dietary lipids.
Answer: Bile
61. The fluid containing emulsifying agents that is secreted by the liver, stored in the gallbladder, and released into the small intestine.
Answer: Glycine and taurine
62. The two amino acids that may be attached to the side-chain carboxyl group of bile acids.
Answer: Steroid hormones
63. Cholesterol-derived hormones that function as chemical messengers.
Answer: Estrogens
64. The female sex hormones involved in female secondary sex characteristics and regulation of the menstrual cycle.
Answer: Androgens
65. The male sex hormones that promote male secondary sex characteristics and muscle growth.
Answer: Progestins
66. The pregnancy hormones that prepare the uterine lining for implantation and suppress ovulation.
Answer: Mineralocorticoids
67. Adrenocorticoid hormones that control the balance of Na⁺ and K⁺ ions in cells and body fluids.
Answer: Glucocorticoids
68. Adrenocorticoid hormones that control glucose metabolism and counteract inflammation.
Answer: Aldosterone
69. The major mineralocorticoid identified in the module.
Answer: Cortisol (hydrocortisone)
70. The major glucocorticoid and the hormone synthesized in the largest amount by the adrenal glands.