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Chapter 5 1. _________ constitute the bulk of animal hair. 0 0.000 a) Tubulin dimers 3 0.007 b) Actin 3 0.007 c) Collagen 0 0.000 d) Myoglobin 447 0.987 e) Keratin filaments## 22. A plot of the binding of oxygen to myoglobin as a function of pO2 gives a _____ shape; a similar plot for hemoglobin gives a _____ shape. 2 0.004 a) sigmoidal; sigmoidal 5 0.011 b) hyperbolic; hyperbolic 448 0.972 c) hyperbolic; sigmoidal## 5 0.011 d) sigmoidal; hyperbolic 1 0.002 e) hyperbolic; exponential 89. Ascorbic acid is required for the production of _____ in collagen. 410 0.976 a) hydroxyproline## 1 0.002 b) aspartate-semialdehyde 1 0.002 c) desmosine 7 0.017 d) hydroxylysine 1 0.002 e) gamma-carboxyglutamic acid 90. Ascorbic acid is required for the production of _____ in collagen. 416 0.902 a) hydroxyproline## 2 0.004 b) aspartate semialdehyde 2 0.004 c) desmosine 32 0.069 d) hydroxylysine 9 0.020 e) gamma-carboxyglutamic acid 91. Ascorbic acid is required for the production of _____ in collagen. 292 0.640 a) hydroxyproline## 28 0.061 b) -carboxyglutamic acid 30 0.066 c) aspartate -semialdehyde 94 0.206 d) hydroxylysine 12 0.026 e) desmosine 92. Ascorbic acid is required for the production of _____ in collagen. 400 0.885 a) hydroxyproline## 15 0.033 b) aspartate-semialdehyde 7 0.015 c) desmosine 23 0.051 d) hydroxylysine 7 0.015 e) gamma-carboxyglutamic acid 129. Bone and tendons contain _____ while hair and nails contain _____. 8 0.017 a) tubulin; keratin 10 0.022 b) actin; keratin 0 0.000 c) collagen; actin 2 0.004 d) tubulin; collagen 441 0.957 e) collagen; keratin## 130. Bone and tendons contain _____ while hair and nails contain _____. 2 0.004 a) tubulin; keratin 1 0.002 b) actin; keratin 0 0.000 c) collagen; actin 0 0.000 d) tubulin; collagen 466 0.994 e) collagen; keratin## 146. During the formation of microfilaments, which of the following occurs? 232 0.503 a) polymerization proceeds slowly at first, then becomes more rapid once a longer polymer has formed## 102 0.221 b) ATP binds to F-actin 59 0.128 c) ATP hydrolysis is catalyzed by G-actin 41 0.089 d) none of the rest 27 0.059 e) F-actin polymerizes, becoming G-actin 147. During the formation of microfilaments, which of the following occurs? 352 0.871 a) polymerization proceeds slowly at first, then becomes more rapid once a longer polymer has formed## 20 0.050 b) ATP binds to F-actin 16 0.040 c) ATP hydrolysis is catalyzed by G-actin 14 0.035 d) None of the rest 2 0.005 e) F-actin polymerizes, becoming G-actin 148. During the formation of microfilaments, which of the following occurs? 148 0.282 a) polymerization proceeds slowly at first, then becomes more rapid once a longer polymer has formed 0 0.000 b) ATP binds to G-actin 36 0.069 c) ATP hydrolysis is catalyzed by F-actin 1 0.002 d) G-actin polymerizes, becoming F-actin 338 0.645 e) All of the rest## 149. During the formation of microfilaments, which of the following occurs? 22 0.057 a) polymerization proceeds quickly at first, then slows after about ten actin monomers have polymerized 94 0.245 b) ATP binds to F-actin 205 0.534 c) ATP hydrolysis is catalyzed by F-actin## 34 0.089 d) none of the rest 27 0.070 e) F-actin polymerizes, becoming G-actin 150. During the formation of microfilaments, which of the following occurs? 173 0.382 a) polymerization proceeds slowly at first, then becomes more rapid once a longer polymer has formed## 85 0.188 b) ATP binds to F-actin 15 0.033 c) ATP hydrolysis is catalyzed by G-actin 169 0.373 d) none of the rest 10 0.022 e) F-actin polymerizes, becoming G-actin 151. During the initial synthesis of collagen molecules, _____ and _____ are most often incorporated into the growing protein. 17 0.037 a) Ser; Pro 6 0.013 b) Ala; Gly 403 0.874 c) Gly; Pro## 30 0.065 d) Ser; Gly 5 0.011 e) Pro; Ala 153. Each kinesin head contains a binding site for _____ and a binding site for _____. 42 0.082 a) tubulin; GTP 27 0.053 b) actin; ATP 2 0.004 c) another kinesin molecule; GTP 436 0.853 d) tubulin; ATP## 4 0.008 e) myosin; ATP 154. Each myosin head contains a binding site for _____ and a binding site for _____. 12 0.026 a) tubulin; GTP 414 0.908 b) actin; ATP## 13 0.029 c) another myosin molecule; ATP 4 0.009 d) none of the rest 13 0.029 e) kinesin; GTP 188. Heme is considered a _____. 316 0.883 a) prosthetic group## 2 0.006 b) catalyst 8 0.022 c) coenzyme 8 0.022 d) none of these choices 23 0.064 e) cofactor 189. Hemoglobin is 50% saturated with oxygen when pO2 = 26 torr. If hemoglobin exhibited hyperbolic binding (as myoglobin does) with 50% saturation at 26 torr. Which of the following statements is correct? (pO2 =100 in the lungs and pO2 = 30 in the tissues; fractional saturation YO2 = pO2 / {K + pO2} and K=p50=pO2 when YO2=0.5) 8 0.017 a) The fractional saturation when pO2 = 30 torr is 0.24 426 0.924 b) Hemoglobin can only use approximately 1/4 of its capacity to deliver O2 to the tissues## 2 0.004 c) Hemoglobin is fully oxidized in the tissues 6 0.013 d) The fractional saturation when pO2 = 100 torr is 0.59 18 0.039 e) None of the rest 195. How does CO2 affect hemoglobin-oxygen binding? 3 0.007 a) none of the rest 12 0.026 b) CO2 binds directly to the oxygen binding site, displacing oxygen and thus promoting the deoxy state 2 0.004 c) CO2 displaces BPG, thus promoting the oxy state 12 0.026 d) CO2 is converted to bicarbonate and H+ which promotes the oxy state 432 0.937 e) CO2 is converted to bicarbonate and H+ which promotes the deoxy state## 196. How does CO2 affect hemoglobin-oxygen binding? 1 0.002 a) none of the rest 1 0.002 b) CO2 binds directly to the oxygen binding site, displacing oxygen and thus promoting the deoxy state 1 0.002 c) CO2 displaces BPG, thus promoting the oxy state 10 0.022 d) CO2 is converted to bicarbonate and H+ which promotes the oxy state 440 0.971 e) CO2 is converted to bicarbonate and H+ which promotes the deoxy state## 197. How does CO2 affect hemoglobin-oxygen binding? 222 0.491 a) none of the rest 37 0.082 b) CO2 binds directly to the oxygen binding site, displacing oxygen and thus promoting the deoxy state 3 0.007 c) CO2 displaces BPG, thus promoting the oxy state 158 0.350 d) The presence of CO2 lower the pH of the solution which promotes the deoxy state## 30 0.066 e) CO2 is converted to bicarbonate and H+ which promotes the oxy state 198. How does CO2 affect hemoglobin-oxygen binding? 1 0.003 a) none of the rest 19 0.049 b) CO2 binds directly to the oxygen binding site, displacing oxygen and thus promoting the deoxy state 4 0.010 c) CO2 displaces BPG, thus promoting the oxy state 16 0.042 d) CO2 is converted to bicarbonate and H+ which promotes the oxy state 344 0.896 e) CO2 is converted to bicarbonate and H+ which promotes the deoxy state## 239. In Hb S, a ___ residue is replaced by a ___ residue. 8 0.019 a) glycine; valine 1 0.002 b) aspartate; lysine 0 0.000 c) glutamate; histidine 1 0.002 d) glycine; isoleucine 410 0.976 e) glutamate; valine## 240. In Hb S, a ___ residue is replaced by a ___ residue. 313 0.679 a) none of the rest## 9 0.020 b) aspartate; lysine 19 0.041 c) glutamate; histidine 108 0.234 d) glycine; valine 11 0.024 e) glycine; isoleucine 241. In Hb S, a valine residue binds to a(n) ___ patch causing ___ of the hemoglobin. 6 0.013 a) none of the rest 10 0.022 b) acidic; unfolding 18 0.039 c) basic; aggregation 402 0.882 d) hydrophobic; aggregation## 20 0.044 e) hydrophilic; unfolding 269. Myoglobin is _____; hemoglobin is _____. 4 0.009 a) monomeric; trimeric 0 0.000 b) dimeric; trimeric 6 0.013 c) monomeric; dimeric 431 0.951 d) monomeric; tetrameric## 11 0.024 e) dimeric; tetrameric 290. The Nobel prize was/were awarded to which of the following individuals: 357 0.804 a) all of the listed individuals## 60 0.135 b) James Watson 5 0.011 c) John Kendrew 4 0.009 d) Max Perutz 18 0.041 e) Linus Pauling 292. The aggregation of Hb S occurs in the ___ state, thus the formation of aggregates is likely to occur at ___. 8 0.017 a) oxy; high altitude 10 0.022 b) deoxy; Hawaiian beaches 420 0.911 c) deoxy; high altitude## 12 0.026 d) oxy; Hawaiian beaches 11 0.024 e) none of the rest 293. The aggregation of Hb S occurs in the ___ state, thus the formation of aggregates is most likely to occur in the ___. 11 0.024 a) oxy; capillaries 7 0.015 b) deoxy; arteries 419 0.927 c) deoxy; capillaries## 15 0.033 d) oxy; arteries 0 0.000 e) none of the rest 296. The central ion of the heme group of hemoglobin is _____. 0 0.000 a) none of these choices 0 0.000 b) Cu(+) 0 0.000 c) Cu(2+) 4 0.009 d) Fe(3+) 457 0.991 e) Fe(2+)## 297. The central ion of the heme group of hemoglobin is _____. 0 0.000 a) none of these choices 0 0.000 b) Cu(+) 1 0.003 c) Cu(2+) 7 0.020 d) Fe(3+) 349 0.975 e) Fe(2+)## 298. The central ion of the heme group of methemoglobin is _____. 1 0.002 a) none of these choices 0 0.000 b) Cu(+) 1 0.002 c) Cu(2+) 462 0.983 d) Fe(3+)## 6 0.013 e) Fe(2+) 299. The central ion of the heme group of methemoglobin is _____. 5 0.011 a) none of the rest 2 0.004 b) Cu+ 3 0.007 c) Cu2+ 399 0.875 d) Fe3+## 47 0.103 e) Fe2+ 300. The central ion of the heme group of metmyoglobin is _____. 3 0.007 a) none of the rest 0 0.000 b) Cu+ 1 0.002 c) Cu2+ 395 0.940 d) Fe3+## 21 0.050 e) Fe2+ 306. The heads of kinesin bind to _____; the light chains of kinesin bind to _____. 453 0.886 a) tubulin; proteins in the membrane of a vesicle## 3 0.006 b) collagen fibers; proteins in the cell membrane 16 0.031 c) proteins in the membrane of a vesicle; actin 13 0.025 d) proteins in the membrane of an organelle; tubulin 25 0.049 e) none of the rest 307. The helical structure of collagen contains _____. 41 0.089 a) three right-handed helices wound around each other in a right-handed triple helix 14 0.030 b) three left-handed helices wound around each other in a left-handed triple helix 367 0.796 c) three left-handed helices wound around each other in a right-handed triple helix## 33 0.072 d) three right-handed helices wound around each other in a left-handed triple helix 5 0.011 e) none of the rest 308. The helical structure of collagen contains _____. 5 0.011 a) three right-handed helices wound around each other in a right-handed triple helix 5 0.011 b) three left-handed helices wound around each other in a left-handed triple helix 429 0.941 c) three left-handed helices wound around each other in a right-handed triple helix## 15 0.033 d) three right-handed helices wound around each other in a left-handed triple helix 2 0.004 e) none of the rest 309. The idea that binding of one molecule of oxygen to hemoglobin enhances further binding of oxygen to hemoglobin is called _____. 0 0.000 a) none of the rest 12 0.039 b) allosterism 288 0.938 c) cooperativity## 2 0.007 d) homologous binding 5 0.016 e) fractional saturation 310. The idea that binding of one molecule of oxygen to hemoglobin enhances further binding of oxygen to hemoglobin is called _____. 1 0.003 a) none of the choices 9 0.025 b) allosterism 342 0.955 c) cooperativity## 4 0.011 d) homologous binding 1 0.003 e) fractional saturation 311. The idea that binding of one molecule of oxygen to hemoglobin enhances further binding of oxygen to hemoglobin is called _____. 5 0.011 a) none of the rest 2 0.004 b) allosterism 440 0.973 c) cooperativity## 3 0.007 d) homologous binding 2 0.004 e) fractional saturation 312. The idea that binding of one molecule of oxygen to hemoglobin enhances further binding of oxygen to hemoglobin is called _____. 13 0.028 a) none of the choices 2 0.004 b) allosterism 453 0.966 c) cooperativity## 1 0.002 d) homologous binding 0 0.000 e) fractional saturation 313. The idea that binding of one molecule of oxygen to myoglobin enhances further binding of oxygen to myoglobin is called _____. 136 0.295 a) none of the choices## 10 0.022 b) allosterism 310 0.672 c) cooperativity 3 0.007 d) homologous binding 2 0.004 e) fractional saturation 314. The individual hemoglobin subunits and myoglobin share similar _____ structure but have rather different _____ structure. 20 0.056 a) secondary; tertiary 12 0.034 b) primary; secondary 16 0.045 c) primary; tertiary 271 0.757 d) secondary and tertiary; primary## 38 0.106 e) primary and secondary; tertiary 396. What is the most prevalent secondary structure observed in the proteins of intermediate filaments? 73 0.158 a) both alpha-helices and beta-helices are observed 304 0.659 b) alpha-helices## 4 0.009 c) alpha-sheets 69 0.150 d) beta-sheets 11 0.024 e) beta-helices 402. What is the prominent type of secondary structure observed in myoglobin? 5 0.011 a) parallel beta-sheets 1 0.002 b) alpha-bends 14 0.030 c) antiparallel beta-sheets 5 0.011 d) beta-helices 436 0.946 e) alpha-helices## 403. What is the prominent type of secondary structure observed in myoglobin? 10 0.028 a) parallel beta-sheets 5 0.014 b) alpha-bends 29 0.081 c) antiparallel beta-sheets 4 0.011 d) beta-helices 310 0.866 e) alpha-helices## 404. What is the prominent type of secondary structure observed in myoglobin? 4 0.009 a) parallel beta-sheets 10 0.022 b) antiparallel beta-sheets 11 0.024 c) coiled-coil 1 0.002 d) left-handed triple helix 427 0.943 e) alpha-helices## 445. When oxygen is bound to the heme group of myoglobin, it is coordinated between _____ and _____. 3 0.010 a) none of the rest 210 0.684 b) E7 His; Fe2+ of heme## 20 0.065 c) E7 His; Fe3+ of heme 7 0.023 d) F8 His; Fe3+ of heme 67 0.218 e) F8 His; Fe2+ of heme 449. Which allosteric effector has the greatest ability to stabilize the deoxy state of hemoglobin? 4 0.009 a) all of the rest have equal ability 441 0.957 b) BPG## 7 0.015 c) CO2 4 0.009 d) O2 5 0.011 e) H+ 450. Which amino acid is critical for crosslinking of collagen trimers? 37 0.080 a) Ser 57 0.124 b) Cys 21 0.046 c) His 331 0.718 d) Lys## 14 0.030 e) Gln 451. Which amino acid is critical for crosslinking of collagen trimers? 21 0.055 a) Ser 86 0.224 b) Cys 24 0.062 c) His 226 0.589 d) Lys## 27 0.070 e) Gln 452. Which amino acid is critical for crosslinking of keratin fibers? 0 0.000 a) Ser 413 0.983 b) Cys## 2 0.005 c) His 5 0.012 d) Lys 0 0.000 e) Gln 475. Which of the following best explains the ability for carbon monoxide (CO) to bind to hemoglobin (Hb) despite the relatively low concentrations of CO? 2 0.004 a) none of the choices 429 0.949 b) CO binds to Hb about 250 times more strongly than oxygen## 18 0.040 c) CO binds to Hb about 5 times more strongly than oxygen 1 0.002 d) CO binds to Hb with less affinity than oxygen 2 0.004 e) CO binds to Hb with an affinity about the same as oxygen 476. Which of the following best explains the ability for carbon monoxide (CO) to bind to hemoglobin (Hb) despite the relatively low concentrations of CO? 6 0.015 a) None of the choices 390 0.965 b) CO binds to Hb about 250 times more strongly than oxygen## 8 0.020 c) CO binds to Hb about 5 times more strongly than oxygen 0 0.000 d) CO binds to Hb with less affinity than oxygen 0 0.000 e) CO binds to Hb with an affinity about the same as oxygen 477. Which of the following best explains the ability for carbon monoxide (CO) to bind to hemoglobin (Hb) despite the relatively low concentrations of CO? 12 0.034 a) none of the choices 258 0.721 b) CO binds to Hb about 250 times more strongly than oxygen## 73 0.204 c) CO binds to Hb about 5 times more strongly than oxygen 4 0.011 d) CO binds to Hb with less affinity than oxygen 11 0.031 e) CO binds to Hb with an affinity about the same as oxygen 491. Which of the following details the nucleotide-binding site when tubulin dimers assemble into microtubules? 105 0.228 a) the alpha site is bound to GTP; the beta site is unoccupied following GTP hydrolysis and release of GDP 25 0.054 b) both alpha and beta sites are bound to GDP 22 0.048 c) both alpha and beta sites are bound to GTP 248 0.538 d) the alpha site is bound to GTP; the beta site is bound to GDP## 61 0.132 e) the alpha site is bound to GDP; the beta site is bound to GTP 492. Which of the following explains the conversion of hemoglobin subunits from deoxy to oxy state? 9 0.020 a) none of the rest 430 0.933 b) all four subunits switch simultaneously## 9 0.020 c) both alpha subunits simultaneously switch first followed by both beta subunits 9 0.020 d) each subunit switches only upon oxygen binding to the particular subunit 4 0.009 e) both beta subunits simultaneously switch first followed by both alpha subunits 498. Which of the following fibers is correctly paired with the protein that forms the fiber? 1 0.002 a) microtubule: tubulin 1 0.002 b) extracellular support fibers: collagen 0 0.000 c) intermediate filaments: keratin 4 0.009 d) microfilaments: actin 455 0.987 e) all of the rest## 503. Which of the following individuals was/were the first to determine the crystal structure of myoglobin? 1 0.002 a) all of the listed individuals 10 0.023 b) James Watson 335 0.755 c) John Kendrew## 56 0.126 d) Max Perutz 42 0.095 e) Linus Pauling 557. Which of the following occurs in hemoglobin upon oxygen binding? 3 0.007 a) the heme Fe2+ is pulled out of the plane of the heme group 0 0.000 b) hemoglobin changes from the R state to the T state 5 0.011 c) the His coordinated to the heme Fe2+ is pushed away from the heme group 438 0.950 d) the central cavity between the four subunits is decreased in size## 15 0.033 e) all of the rest occur 558. Which of the following occurs in hemoglobin upon oxygen binding? 33 0.072 a) the heme Fe2+ is pushed away from the plane of the heme group 25 0.054 b) hemoglobin changes from the R state to the T state 368 0.798 c) the His coordinated to the heme Fe2+ is pulled towards the heme group## 19 0.041 d) the central cavity between the four subunits is increased in size 16 0.035 e) all of the rest occur 559. Which of the following occurs in hemoglobin upon oxygen binding? 13 0.042 a) the heme Fe2+ is pulled out of the plane of the heme group 1 0.003 b) hemoglobin changes from the R state to the T state 18 0.059 c) the His coordinated to the heme Fe2+ is pushed away from the heme group 265 0.863 d) the central cavity between the four subunits is decreased in size## 10 0.033 e) all of the rest occur 560. Which of the following occurs in hemoglobin upon oxygen binding? 11 0.024 a) the heme Fe2+ pushed away from the plane of the heme group 331 0.732 b) hemoglobin changes from the T state to the R state## 32 0.071 c) the Arg coordinated to the heme Fe2+ is pulled towards the heme group 27 0.060 d) the central cavity between the four subunits is increased in size 51 0.113 e) all of the rest occur 561. Which of the following occurs in hemoglobin upon oxygen binding? 2 0.004 a) the heme Fe2+ is pulled out of the plane of the heme group 1 0.002 b) hemoglobin changes from the R state to the T state 1 0.002 c) the His coordinated to the heme Fe2+ is pushed away from the heme group 458 0.977 d) the central cavity between the four subunits is decreased in size## 6 0.013 e) all of the rest occur 562. Which of the following occurs in hemoglobin upon oxygen binding? 0 0.000 a) the heme Fe2+ is pulled towards the plane of the heme group 5 0.011 b) hemoglobin changes from the T state to the R state 4 0.009 c) the His coordinated to the heme Fe2+ is pulled towards the heme group 202 0.443 d) the central cavity between the four subunits is decreased in size 245 0.537 e) all of the rest occur## 563. Which of the following occurs in hemoglobin upon oxygen binding? 7 0.020 a) the heme Fe(2+) is pulled out of the plane of the heme group 1 0.003 b) hemoglobin changes from the R state to the T state 7 0.020 c) the His coordinated to the heme Fe(2+) is pushed away from the heme group 323 0.902 d) the central cavity between the four subunits is decreased in size## 20 0.056 e) all of the rest occur 564. Which of the following occurs in hemoglobin upon oxygen binding? 1 0.002 a) the heme Fe2+ is pulled out of the plane of the heme group 5 0.010 b) hemoglobin changes from the R state to the T state 1 0.002 c) the His coordinated to the heme Fe2+ is pushed away from the heme group 478 0.939 d) the central cavity between the four subunits is decreased in size## 23 0.045 e) all of the rest occur 565. Which of the following occurs in hemoglobin upon oxygen binding? 2 0.005 a) the heme Fe2+ pushed away from the plane of the heme group 376 0.895 b) hemoglobin changes from the T state to the R state## 2 0.005 c) the Arg coordinated to the heme Fe2+ is pulled towards the heme group 30 0.071 d) the central cavity between the four subunits is increased in size 10 0.024 e) all of the rest occur 566. Which of the following occurs in hemoglobin upon oxygen binding? 38 0.084 a) the heme Fe(2+) is pulled into the plane of the heme group## 291 0.642 b) hemoglobin changes from the T state to the R state## 27 0.060 c) the His coordinated to the heme Fe(2+) is pulled towards the heme group## 5 0.011 d) the central cavity between the four subunits is increased in size 92 0.203 e) all of the rest occur 567. Which of the following occurs in hemoglobin upon oxygen binding? 7 0.014 a) the heme Fe2+ is pulled into the plane of the heme group 44 0.086 b) hemoglobin changes from the T state to the R state 61 0.119 c) the His coordinated to the heme Fe2+ is pulled towards the heme group 115 0.225 d) the central cavity between the four subunits is decreased in size 284 0.556 e) all of the rest occur## 589. Which of the following statements does not apply to collagen? 11 0.022 a) The triple helical structure twists in the right-handed direction. 395 0.773 b) Cross-links between neighbouring hydroxylated Lys residues stabilize the helix.## 7 0.014 c) Glycine at every third position is essential for the stability of the triple helical structure. 92 0.180 d) One single polypeptide forms a left-handed helix. 6 0.012 e) It contains hydroxylated amino acids. 590. Which of the following statements does not apply to collagen? 2 0.007 a) The triple helical structure twists in the right-handed direction. 253 0.824 b) Cross-links between neighbouring hydroxylated Lys residues stabilize the helix.## 29 0.094 c) Glycine at every third position is essential for the stability of the triple helical structure. 16 0.052 d) One single polypeptide forms a left-handed helix. 7 0.023 e) It contains hydroxylated amino acids. 591. Which of the following statements does not apply to collagen? 26 0.055 a) The triple helical structure twists in the right-handed direction. 49 0.104 b) Cross-links between neighbouring Lys residues stabilize the helix. 7 0.015 c) Glycine at every third position is essential for the stability of the triple helical structure. 382 0.813 d) One single polypeptide forms a right-handed helix.## 4 0.009 e) It contains hydroxylated amino acids. 592. Which of the following statements does not apply to collagen? 262 0.559 a) The triple helical structure twists in the left-handed direction.## 184 0.392 b) Cross-links between neighbouring Lys residues stabilize the helix. 5 0.011 c) Glycine at every third position is essential for the stability of the triple helical structure. 6 0.013 d) One single polypeptide forms a left-handed helix. 12 0.026 e) It contains hydroxylated amino acids. 600. Which of the following statements is not true about carbonic anhydrase? 15 0.033 a) It is particularly abundant in red blood cells 18 0.039 b) It catalyzes the conversion of bicarbonate to CO2 in the lung 22 0.048 c) It catalyzes the conversion of dissolved CO2 to bicarbonate in the tissue 280 0.614 d) It is not found in plant tissues## 121 0.265 e) It is found in all animals 601. Which of the following statements is true about carbonic anhydrase? 18 0.039 a) It is particularly abundant in red blood cells 74 0.161 b) It catalyzes the conversion of bicarbonate to CO2 in the lung 98 0.213 c) It catalyzes the conversion of dissolved CO2 to bicarbonate in the tissue 3 0.007 d) It is found in most tissues 267 0.579 e) All of the rest are correct## 626. Why is the decreased affinity of fetal hemoglobin for BPG advantageous to the fetus? 26 0.056 a) With fewer BPG molecules bound there are more heme residues available for O2 binding 10 0.022 b) BPG is available to bind to fetal myoglobin, helping to release O2 in fetal muscle tissue 3 0.007 c) Decreased BPG binding biases the fetal hemoglobin toward the T state 2 0.004 d) More free BPG is available to bind to adult hemoglobin, resulting in a shift of adult hemoglobin to the R state 420 0.911 e) It reduces fetal hemoglobin's P50## 627. With respect to oxygen saturation, hemoglobin is _____ saturated at the pO2 of the lungs and _____ saturated at the pO2 of the tissue 454 0.968 a) >90%; between 30 and 70%## 0 0.000 b) 20%; 20% 1 0.002 c) 25%; 20% 4 0.009 d) 50%; between 30 and 70% 10 0.021 e) 50%; 20% 635. ____ forms microfilaments in cells. 17 0.038 a) Tubulin dimers 430 0.949 b) Actin## 1 0.002 c) Collagen 1 0.002 d) Myoglobin