AAMC MCAT test 3r

Printing Guide Use this printing guide as a reference to print selected sections of this practice test To print, click the PRINTER icon located along the top of the window and enter one of the following options in the PRINT RANGE section of the print dialog window: To Print Enter Print Range Options Complete Practice Test Click ALL radio button Physical Sciences Section Click PAGES FROM radio button and enter pages to 26 Verbal Reasoning Section Click PAGES FROM radio button and enter pages 27 to 47 Writing Sample Section Click PAGES FROM radio button and enter pages 48 to 50 Biological Sciences Section Click PAGES FROM radio button and enter pages 51 to 74 Periodic Table Click PAGES FROM radio button and enter page to Answer Sheet Click PAGES FROM radio button and enter page 75 to 75 This document has been encoded to link this download to your member account The AAMC and its Section for the MCAT hold the copyrights to the content of this Practice Test Therefore, there can be no sharing or reproduction of materials from the Practice Test in any form (electronic, voice, or other means) If there are any questions about the use of the material in the Practice Test, please contact the MCAT Information Line (202828-0690) MCAT Practice Test 3R Physical Sciences Time: 100 minutes Questions: 1-77 Most questions in the Physical Sciences test are organized into groups, each containing a descriptive passage After studying the passage, select the one best answer to each question in the group Some questions are not based on a descriptive passage and are also independent of each other If you are not certain of an answer, eliminate the alternatives that you know to be incorrect and then select an answer from the remaining alternatives Indicate your selected answer by marking the corresponding answer on your answer sheet A periodic table is provided for your use You may consult it whenever you wish This document has been encoded to link this download to your member account The AAMC and its Section for the MCAT hold the copyrights to the content of this Practice Test Therefore, there can be no sharing or reproduction of materials from the Practice Test in any form (electronic, voice, or other means) If there are any questions about the use of the material in the Practice Test, please contact the MCAT Information Line (202828-0690) Periodic Table of the Elements H He 4.0 10 1.0 Li Be B C N O F Ne 6.9 9.0 10.8 12.0 14.0 16.0 19.0 20.2 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar 23.0 24.3 27.0 28.1 31.0 32.1 35.5 39.9 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 39.1 37 Rb 85.5 55 Cs 132.9 87 40.1 38 Sr 87.6 56 Ba 45.0 39 Y 88.9 57 La* 47.9 40 Zr 91.2 72 50.9 41 52.0 42 Nb Mo 92.9 73 Hf Ta 95.9 74 W 54.9 43 Tc (98) 75 Re 55.8 44 Ru 101.1 76 Os 58.9 45 Rh 102.9 77 Ir 58.7 46 Pd 106.4 78 Pt Ag 107.9 79 Au Cd 112.4 80 Hg 200.6 69.7 49 In 114.8 81 Tl 204.4 72.6 50 Sn 118.7 82 Pb 207.2 74.9 51 Sb 121.8 83 Bi 209.0 79.0 52 Te 127.6 84 Po (209) 79.9 53 I 126.9 85 At (210) 83.8 54 Xe 131.3 86 Rn 138.9 89 178.5 104 180.9 105 183.9 106 186.2 107 190.2 108 192.2 109 Fr Ra Ac† Unq† Unp Unh Uns Uno Une (223) (226) (227) (261) (262) 58 (263) 59 (262) 60 (265) 61 (267) 62 63 64 65 66 67 68 69 70 71 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 140.1 90 140.9 91 144.2 92 (145) 93 150.4 94 152.0 95 157.3 96 158.9 97 162.5 98 164.9 99 167.3 100 168.9 101 173.0 102 175.0 103 † 197.0 65.4 48 137.3 88 * 195.1 63.5 47 (222) Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr 232.0 (231) 238.0 (237) (244) (243) (247) (247) (251) (252) (257) (258) (259) (260) Passage I A series of chemical reactions was carried out to study the chemistry of lead Reaction Initially, 15.0 mL of 0.300 M Pb(NO3)2(aq) was mixed with 15.0 mL of 0.300 M Na2SO4(aq) All the Pb(NO3)2 reacted to form Compound A, a white precipitate Compound A was removed by filtration Reaction Next, 15.0 mL of 0.300 M KI(aq) was added to Compound A The mixture was agitated and some of Compound A dissolved In addition, a yellow precipitate of PbI2(s) was formed Reaction The PbI2(s) was separated and mixed with 15.0 mL of 0.300 M Na2CO3(aq) A white precipitate of PbCO3(s) formed All of the PbI2(s) was converted into PbCO3(s) Reaction The PbCO3(s) was removed by filtration and a small sample gave off a gas when treated with dilute HCl Pb(OH)2(s) is slightly soluble in water How would the amount of Pb(OH)2(s) that normally dissolves in L of water be affected if the pH were 9.0? A) Less would dissolve B) The same amount would dissolve C) More would dissolve D) There is no way to predict the effect of the change in pH of the water A soluble form of Pb2+ can be carefully added to a solution to sequentially precipitate and separate anions present in the solution When Pb2+ is added, in what order will the following anions be precipitated? A) SO42- then IB) CO32- then IC) SO42- then CO32D) I- then CO325 How many moles of Na+ ions are there in the initial Na2SO4(aq) solution used in Reaction 1? A) 0.0018 mole B) 0.009 mole C) 0.045 mole D) 0.090 mole Which of the following reactions depicts the formation of the gas in Reaction 4? A) PbCO3(s) + HCl(aq) → PbCl2(aq) + CO2(g) + H2O(l) B) Na2CO 3(aq) + HCl(aq) → NaCl(aq) + CO2(g) + H2O(l) C) PbCO 3(s) + HCl(aq) → PbC2(s) + Cl2(g) + H2O(l) D) PbI 2(s) + HCl(aq) → PbCl2(aq) + HI(g) The identity of Compound A is: A) Pb(NO3)2 B) PbI2 C) NaNO3 D) PbSO4 Sharing or reproducing this material in any form is a violation of the AAMC copyright Passage II At the critical point, the density of liquid CO2 is equal to the density of gaseous CO2 This occurs at specific conditions of temperature and pressure At temperatures and pressures above the critical point values, CO2 is deemed supercritical For a supercritical fluid, the density and ability to dissolve other substances are similar to values expected for liquids The following figures give phase data for CO2 In Figure 2, which of the points (A-D) is the critical point for CO2? A) A B) B C) C D) D In an extraction of an organic oil, which of the following is an advantage of using supercritical CO2? A) It reacts with most organic compounds B) It is easily handled at room temperature C) It crystallizes easily D) It is easily removed by evaporation Water is a liquid at room temperature, yet CO2 at room temperature is liquid only at high pressures Which of the following best explains this? Figure Phase diagram for CO2 A) CO2 is polar and has strong intermolecular forces B) CO2 is nonpolar and has strong intermolecular forces C) CO2 is polar and has weak intermolecular forces D) CO2 is nonpolar and has weak intermolecular forces According to Figure 1, what is the critical temperature and pressure of CO2? A) –56.1o C and 6.0 atm B) –54.1o C and 119.0 atm C) 31.1o C and 75.3 atm D) 25.0o C and 1.0 atm 10 Which of the following compounds is most soluble in supercritical CO2? A) NaCl B) C2H5OC2H5 C) NH4NO3 D) KOH Figure Isothermal curves for CO2 near the critical point V (x 104) is relative to V = 1.000 at 0oC and 1.000 atm Sharing or reproducing this material in any form is a violation of the AAMC copyright Passage III When X-rays are produced in an X-ray tube, two types of X-ray spectra are observed: continuous spectra and line spectra intensity, I, which is proportional to the number of Xray photons emitted at λ The scientist then graphed the results of the experiment, as shown in Figure A continuous spectrum is produced by bremsstrahlung, the electromagnetic radiation produced when free electrons are accelerated during collisions with ions A line spectrum results when an electron having sufficient energy collides with a heavy atom, and an electron in an inner energy level is ejected from the atom An electron from an outer energy level then fills the vacant inner energy level, resulting in emission of an X-ray photon For example, if an electron in the n = energy level is ejected from an atom, an electron in the n = level of the atom can fill the vacancy created in the n = level, and a photon with an energy equal to the energy difference between the two levels will be emitted A scientist produced both types of spectra using the Xray tube shown in Figure below Figure X-ray intensity versus wavelength 11 In Figure 2, which of the following represents the source of emission peaks P1 and P2? A) Bremsstrahlung B) Absorption of X-ray photons resulting in electronic excitations in atoms C) Emission of X-ray photons as a result of electronic transitions in atoms D) Acceleration of electrons in a magnetic field 12 Based on the tube in Figure 1, to maintain an electron current of 0.005 A and a potential drop of 105 V between the anode and the cathode, approximately how much power must the tube consume? Figure Heated cathode X-ray tube The tube contains a heated filament cathode (C), which emits electrons A power supply (LV) regulates the filament temperature, the electrical current in the tube, and the number of X-rays produced at the anode (A) Another power supply (HV) regulates electron acceleration A) x 102 W B) x 103 W C) x 105 W D) x 107 W The scientist used an X-ray tube to determine the relationship between X-ray wavelength, λ, and X-ray Sharing or reproducing this material in any form is a violation of the AAMC copyright 13 The ionization potentials for electrons in the n = 1, 2, and energy levels of Pb are 1,400 x 10-17 J, 240 x 10-17J, and 48 x 10-17 J, respectively When an electron in the n = level fills a vacancy in the n = level, what is the energy of the X ray that is emitted? A) 1.92 x 10-15 J B) 2.40 x 10-15 J C) 1.16 x 10-14 J D) 1.40 x 10-14 J 14 According to the passage, bremsstrahlung will NOT be produced by collisions between electrons and: A) He B) He2+ C) Li1+ D) protons 15 In order to increase the maximum kinetic energy of electrons colliding with the anode, the scientist made which of the following changes? A) The voltage of HV was increased B) The voltage of HV was decreased C) The voltage of LV was increased D) The voltage of LV was decreased 16 In Figure 2, peaks P1 and P2 were produced by events that occurred with unequal probabilities Which peak was produced by the more probable event? A) B) C) D) P1, because the peak has the longer wavelength P1, because the peak has the lower intensity P2, because the peak has the longer wavelength P2, because the peak has the higher intensity Sharing or reproducing this material in any form is a violation of the AAMC copyright Passage IV Many chemical bonds are not purely ionic or covalent, but polar covalent For example, in an HCl bond, chlorine has a greater attraction for electrons than hydrogen does and therefore develops a partial negative charge with respect to the hydrogen atom If the partial charges are separated by a known distance, the dipole moment, a measure of the charge separation in a bond or molecule, can be calculated by the following equation dipole moment = charge x separation distance Dipole moments are usually measured in debyes (D), where D = 3.34 x 10-30 coulomb · meter The molecular geometry of some simple molecules can be determined based on the presence or absence of a net dipole moment in the molecule The observed molecular dipole moments of various compounds are reported in Table 17 Which of the following best explains the observed molecular dipole moment of SnBr4? A) Sn and Br have the same effective nuclear charge B) Sn and Br are the same size C) Sn attracts electrons more strongly than predicted by its electronegativity D) The geometry of the molecule causes the bond moments to cancel 18 Which of the following figures most accurately depicts the σ2s electron cloud in the NO molecule? A) B) C) Table Dipole Moments for Various Compounds Molecule Dipole moment (D) SnBr4 HgBr2 SO2 1.47 HF 1.82 HNO3 2.17 BaO 7.95 KCl 10.27 D) 19 Based on the observed dipole moment of HF in Table 1, what is the observed dipole moment for HCl? A) 0.02 D B) 1.08 D C) 4.22 D D) 8.97 D 20 Which of the following best explains why HCl bonds are polar covalent? A) H atoms are smaller than Cl atoms B) H atoms are more electronegative than Cl atoms C) Cl and H atoms have equal electronegativities D) Cl atoms have a greater effective nuclear charge than H atoms Sharing or reproducing this material in any form is a violation of the AAMC copyright 21 If an O atom is removed from a CO2 molecule, the observed molecular dipole moment will: A) decrease, because a lone pair of electrons will be formed on the carbon B) decrease, because the net charge will increase C) remain constant, because the geometry will not change D) increase, because a charge separation will develop 22 Which of the two compounds, PCl3 or PCl5, can be expected to have a larger dipole moment? A) PCl3, because its geometry is trigonal planar B) PCl3, because its geometry is pyramidal C) PCl5, because its geometry is octahedral D) PCl5, because its geometry is trigonal bipyramidal Sharing or reproducing this material in any form is a violation of the AAMC copyright 10 166 According to the hypothesis described in the passage, the bacteria that entered primitive eukaryotic cells were able to carry out which of the following functions that the primitive eukaryotic cells could NOT? A) Glycolysis B) Krebs cycle and electron transport C) Cell division D) Transcription and translation 167 Most proteins in present-day mitochondria are made by cytoplasmic ribosomes from mRNA transcribed from nuclear genes Can this fact be reconciled with the hypothesis described in the passage? A) Yes; the transfer of genes from symbionts to the eukaryotic nucleus could have occurred during the last billion years of evolution B) Yes; this difference from bacteria is unimportant, because the many similarities between bacteria and mitochondria provide sufficient evidence in favor of the hypothesis C) No; the fact that mitochondrial proteins are made in the cytoplasm is convincing evidence that mitochondria not have a bacterial origin D) No; because bacteria can make all their own proteins and mitochondria cannot, this disproves the hypothesis 169 According to the hypothesis in the passage, what is the most likely explanation for the origin(s) of the two mitochondrial membranes? A) Both inner and outer membranes were derived from folding of the prokaryotic plasma membrane B) Both inner and outer membranes were derived from invagination of the eukaryotic plasma membrane C) The inner membrane was derived from folding of the prokaryotic plasma membrane, and the outer from invagination of the eukaryotic plasma membrane D) The inner membrane was derived from invagination of the eukaryotic plasma membrane, and the outer from folding of the prokaryotic plasma membrane 170 Which of the following pieces of evidence most strongly supports the hypothesis of mitochondrial origin described in the passage? A) Mitochondria have fewer genes than typical bacterial cells have B) Mitochondria contain hundreds of different enzymes C) The diameters of mitochondria and typical presentday bacteria are approximately equal D) Nitrogen-fixing bacteria live symbiotically inside the cells of present-day plants 168 The chemical gramicidin inserts into membranes and creates an artificial pathway for proton movement Based on Figure 1, if mitochondria are treated with gramicidin, the rate of ATP synthesis will most likely: A) increase, because of increased proton movement back into the mitochondria B) decrease, because of a decreased rate of hydrogenatom donation by NADH C) decrease, because the proton gradient will rapidly reach equilibrium D) not be altered, because sufficient protons will remain between the membranes to generate ATP Sharing or reproducing this material in any form is a violation of the AAMC copyright 61 171 To support the symbiotic hypothesis presented in the passage, mitochondria should be similar to bacteria in which of the following ways? A) They should use 80S ribosomes B) They should be incapable of binary fission C) They should have circular DNA D) They should be capable of anaerobic respiration 172 The chemical valinomycin inserts into membranes and causes the movement of K+ into the mitochondria Based on Figure 1, if mitochondria are treated with valinomycin, the rate of ATP synthesis in the mitochondria will most likely: A) decrease, because the K+ will compete with protons at the active site on ATP synthetase B) decrease, because movement of K+ into the mitochondrial compartments will disrupt proton movement into the intermembrane space C) increase, because the net positive charge in the mitochondria will cause increased movement of protons into the intermembrane space D) increase, because the additional positive charge will further activate ATP synthetase Sharing or reproducing this material in any form is a violation of the AAMC copyright 62 Passage VI Carvone (shown below) can exist as either of two enantiomers One of them, (+)-carvone, provides the characteristic odor in caraway seed oil, whereas (-)carvone is responsible for the fragrance of spearmint oil Figure Vacuum fractional distillation apparatus A chemist attempted to isolate (+)-carvone from caraway seed oil, which consists almost entirely of (+)carvone and limonene (shown below) 173 When the caraway seed oil is heated, which of the two components will most likely distill first? A) Limonene, because it has the lower boiling point B) Limonene, because it has the higher boiling point C) (+)-Carvone, because it has the lower boiling point D) (+)-Carvone, because it has the higher boiling point 174 The most likely function of the ebulliator is to: Because the two compounds have very different boiling points, the chemist decided to separate them by vacuum fractional distillation The apparatus in Figure was assembled, and a sample of caraway seed oil was placed in the distillation flask An ebulliator was lowered into the distillation flask to introduce small air bubbles into the system The fractionating column and distillation head were wrapped with glass wool, and the apparatus was connected with thick tubing to a vacuum source The contents of the distillation flask were heated, and two fractions were collected in the receiving flask A) keep the condensed vapors cool in the receiving flask B) promote the establishment of a high vacuum in the system C) prevent superheating of the liquid to be distilled D) provide an outlet when the pressure inside the system becomes too high 175 Which of the following experimental modifications will most likely improve the degree of separation between limonene and (+)carvone? A) Heating the distillation flask at a slower rate B) Using a vacuum source that can achieve a lower pressure inside the distillation apparatus C) Cooling the condenser with ice water D) Using a shorter fractionating column Sharing or reproducing this material in any form is a violation of the AAMC copyright 63 176 Carvone is shown below with certain carbon atoms labeled (+)-Carvone and (–)-carvone differ in the orientations of the substituents around which of the following carbon atoms? A) Carbon only B) Carbon only C) Carbons and only D) Carbons 2, 5, and only 177 If a leak develops in the vacuum distillation apparatus, the boiling points of the two components of caraway seed oil will: A) both increase B) both decrease C) both remain the same D) become more similar Sharing or reproducing this material in any form is a violation of the AAMC copyright 64 Passage VII In humans, Hormone X is a protein that induces normal cells to admit more Ca2+ To examine the mode of action of Hormone X, a biologist screened thousands of families for inherited Hormone X deficiencies The screen turned up two (unrelated) families in which many males but no females had a defect in their ability to respond to Hormone X The biologist performed a series of experiments on cells isolated from females and the affected males in the two families to determine: 1) the pathway between hormone binding and Ca2+ entry in a normal cell, and 2) the point in the pathway where the defect occurs in the males The following results were obtained: In both families, none of the isolated cells from affected males had an elevated influx of Ca2+ after treatment with Hormone X Hormone X bound to Protein R of all cells examined Protein R was smaller than normal in cells from affected males of Family 1, but its size was absolutely normal in all other cells examined In intact cells, Protein R phosphorylated Protein P in the cells from females only When activated Protein R was isolated from females, it could phosphorylate Protein P isolated from affected males of Family 1, but not Family Phosphorylated Protein P was necessary and sufficient to increase the rate of Ca2+ entry in cells from females 179 Which of the following protein(s) is most likely to utilize ATP for its action? A) Hormone X only B) Protein R only C) Protein P only D) Both Hormone X and Protein P 180 Among the following choices, the most likely function of phosphorylated Protein P is as a: A) Na+/K+ pump B) phosphatase C) membrane channel D) hormone receptor 181 In the normal cellular response to Hormone X, the influx of Ca2+ should stop immediately when: A) Hormone X no longer binds to Protein R B) the complex of Hormone X and Protein R undergoes endocytosis C) synthesis of Protein P is terminated D) Protein P is dephosphorylated 182 Based on the passage, the mutation in the DNA in affected males from Family most likely results in: A) the replacement of a single amino acid in Protein R B) the replacement of a single amino acid in Protein P C) the introduction of a premature stop codon in Protein R D) the introduction of a premature stop codon in Hormone X 178 Assuming defective Hormone X response is Xlinked, which children of an affected male will most likely be unable to respond to Hormone X? A) All of the males and all of the females B) Half of the males and half of the females C) None of the males and half of the females D) None of the males and none of the females Sharing or reproducing this material in any form is a violation of the AAMC copyright 65 Passage VIII When Compound is heated with sodium ethoxide, Compounds and are formed (Reaction 1) Two chemists each proposed a mechanism for Reaction Mechanism A HBr is eliminated from Compound to form a symmetrical vinyl carbene, Intermediate A, which subsequently rearranges to form Compound Ethoxide abstracts a proton from Compound to produce a carbanion, Intermediate B, which rearranges with a loss of bromide to form Compound To distinguish between the mechanisms, the chemists designed an isotopic labeling experiment They prepared compounds (Compounds and 5) that were labeled with carbon-14 (14C), and they treated each with potassium t-butoxide (see Scheme 1) Because Compounds and formed varying ratios of Compounds and 7, the chemists ruled out Mechanism A Mechanism B Sharing or reproducing this material in any form is a violation of the AAMC copyright 66 185 Which of the following by-products are formed in Reaction 1? A) NaBr and EtOH B) HBr and NaOEt C) Br2 and NaOEt D) EtBr and NaOH 186 Compounds and can be distinguished from each other by all of the following techniques EXCEPT: A) infrared spectroscopy B) proton NMR C) gas-liquid chromatography D) specific rotation 187 The transformation of Compound to Compound involves which of the following changes in hybrid orbitals? A) sp2 to sp B) sp2 to sp3 C) sp3 to sp2 D) sp to sp3 Scheme 183 Based on the results of Scheme 1, the chemists most likely ruled out Mechanism A because they assumed that a symmetrical intermediate should rearrange to form: A) Compound only B) Compound only C) equal amounts of Compounds and D) neither Compound nor Compound 184 Compound most likely is formed as a result of which of the following types of reactions? A) Elimination B) Substitution C) Cyclization D) Halogenation Sharing or reproducing this material in any form is a violation of the AAMC copyright 67 These questions are not based on a descriptive passage and are independent of each other 188 An intravenous infusion causes a sharp rise in the serum level of albumin (the major osmoregulatory protein in the blood) This will most likely cause an: A) increase in the immune response B) increase in tissue albumin levels C) outflow of blood fluid to the tissues D) influx of tissue fluid to the bloodstream 192 The compound below is sold under the name Proton-Sponge® Is this compound likely to be a good nucleophile? A) Yes, because it is a strong base B) Yes, because the nitrogens have high electron density C) No, because it is aromatic D) No, because the nitrogens are sterically hindered 189 Two animals would be considered to be closely related if they were in the same: A) class B) genus C) order D) family 190 Ducklings will tend to follow any large moving object they encounter during a critical period after hatching This type of behavior is termed: A) imprinting B) habituation C) conditioning D) discrimination 191 Which of the following alkanes has the lowest heat of combustion per CH2 group? A) Cyclopropane B) Cyclobutane C) Cyclohexane D) Cycloheptane Sharing or reproducing this material in any form is a violation of the AAMC copyright 68 Passage IX Plasma clearance refers to the capacity of the kidney to remove a substance from the plasma It is determined by comparing the concentrations of the substance in the plasma and the urine, and then calculating the rate at which the substance appears in the urine Plasma clearance is affected by the tubular transport maximum (Tm) of a substance The Tm is the maximum rate of transport (mg/min) at which a substance can be reabsorbed by the kidney That is, if the filtration rate of a substance exceeds its Tm, the substance will begin to appear in the urine The Tm for glucose averages 320 mg/min in an adult human Two experiments were done to study the plasma clearance of Substance A, a hexose that readily enters the glomerular filtrate Experiment First, researchers measured the concentrations of Substance A in the plasma and urine of a volunteer Later, they determined the concentrations of glucose in the volunteer's plasma and urine In each trial, the test substance was injected intravenously and continuously during measurement Results are shown in Figure Experiment The effect of antidiuretic hormone (ADH) on the plasma clearance of Substance A was tested The volunteer was given two dosages of ADH during two separate trials The first dosage was within the normal physiological range of concentrations and affected the renal reabsorption of water The second dosage, which was much higher than the normal physiological concentration, affected urine output by increasing blood pressure 193 According to the passage, the Tm represents the rate of plasma filtration that just exceeds the: A) rate of concentration of the substance in the glomerular filtrate B) rate of concentration of the substance in the urine C) capacity of the kidney tubules to reabsorb the substance D) capacity of the bladder to store and excrete the substance 194 Under normal conditions, the tubular load of glucose (the amount/min that filters into the kidney tubules) is approximately 125 mg/min The amount of glucose in the urine under these conditions is approximately: A) mg/min B) 125 mg/min C) 195 mg/min D) 515 mg/min 195 A lower-than-normal blood pressure will cause which of the following effects on the rate of plasma clearance of Substance A? Figure Plasma clearance of Substance A and glucose A) An increase, because the concentration of Substance A in the urine will increase B) An increase, because the ADH levels will be very low C) A decrease, because the decreased rate of urine output will allow more reabsorption by the kidney D) A decrease, because ADH levels will be very high Sharing or reproducing this material in any form is a violation of the AAMC copyright 69 196 Equal concentrations of mg/mL of Substance A and glucose are found in a volunteer's plasma Based on Figure 1, which substance will the kidney clear from the plasma more rapidly? A) Substance A, because the slope of the clearance line for Substance A is higher than that for glucose B) Substance A, because Substance A reaches its Tm at a lower plasma concentration than does glucose C) Glucose, because glucose reaches its Tm at a higher plasma concentration than does Substance A D) Glucose, because the slope of the clearance line for glucose is lower than that for Substance A 197 According to Figure 1, at approximately what plasma concentration of glucose is the Tm (320 mg/min) reached? A) 6.5 mg/mL B) 10.0 mg/mL C) 11.5 mg/mL D) 12.5 mg/mL 198 In Experiment 2, the increased blood pressure resulting from the higher-than-normal concentration of ADH most likely affected the urinary output of Substance A by increasing the: A) glomerular filtration rate B) Tm of solutes C) water reabsorption from the tubules D) concentrating ability of the loop of Henle 199 Where in the nephron is most reabsorption of glucose likely to occur? A) Glomerulus B) Proximal tubule C) Distal tubule D) Loop of Henle Sharing or reproducing this material in any form is a violation of the AAMC copyright 70 Passage X Osteoporosis is a pathological decrease of 35 to 50% in a person's bone mass, which may increase the likelihood of pelvic and wrist fractures and result in back pain or "dowager's hump" due to compression and fracture of the vertebrae Although all individuals (male and female) steadily lose 0.5 to 1.0% of their bone mass per year after the age of 40, this decline is accelerated in postmenopausal women, who show a loss of to 3% per year for the to 10 years immediately following menopause They then revert to the slower rate of loss Aging-related abnormalities in parathyroid hormone and calcitonin secretion contribute to the slow decline of bone mass in both men and women, as does decreased production of active vitamin D by the kidney The accelerated postmenopausal bone loss in women appears to be directly linked to estrogen deficiency, although the exact mechanism of this linkage is unknown Currently, hormone replacement therapies and dietary calcium supplementation are used in the prevention of osteoporosis in women Because estrogen therapy may increase the risk of developing uterine and breast cancer, patients on estrogens usually also receive low doses of progesterone analogues, which appear to substantially diminish this risk Recently, calcitonin analogues have also been developed for the treatment and prevention of osteoporosis 200 In addition to the effects of estrogen deficiency, the most likely reason that more women than men suffer from osteoporosis is that women, compared to men, have: A) lower bone density B) fewer vertebrae C) less efficient mechanisms for calcium uptake D) less efficient vitamin D production 201 Postmenopausal women receiving estrogen and progesterone therapy will most likely experience which of the following side effects? A) Breast tissue will atrophy B) Vaginal tissue will dry out C) Periodic menstruation will resume D) Lactation will be induced 202 Production of which of the following hormones will be inhibited by the administration of dietary calcium to prevent osteoporosis? A) Growth hormone B) Calcitonin C) Thyroid hormone D) Parathyroid hormone 203 A man is treated with low doses of an estrogen analogue to destroy an estrogen-responsive adrenal tumor Compared to an age-matched control (no estrogen treatment), this patient's chances of developing osteoporosis will most likely be: A) increased B) decreased C) approximately the same D) approximately the same, but the disease will appear at an earlier age 204 Osteoblasts, which form bone, and osteoclasts, which resorb it, work together to cause continuous bone remodeling In a person suffering from osteoporosis, which of the following combinations of changes in the activity of these cell types will most likely occur? A) Increased osteoblast and decreased osteoclast activity B) Increased osteoblast and increased osteoclast activity C) Decreased osteoblast and decreased osteoclast activity D) Decreased osteoblast and increased osteoclast activity Sharing or reproducing this material in any form is a violation of the AAMC copyright 71 Passage XI During an experimental workup procedure, a chemist treated a starting material with NaOH in the solvent acetone [(CH3)2C=O]; however, the starting material was recovered unreacted Instead, the chemist isolated a small amount of Product A (shown below) Product A The chemist determined that Product A resulted from the aldol self-condensation of acetone Product A was identified based on the following observations Observations about Product A Elemental analysis of Product A indicated that it consisted only of carbon, hydrogen, and oxygen Product A had a molecular weight of 116 g/mole Characteristic signals in the infrared spectrum of Product A included a broad band at 3400 cm1 and an intense signal at 1720 cm-1 Product A was a methyl ketone because it gave a positive iodoform test When Product A was treated with Br2 in CCl4, the red bromine color persisted, because no carbon-carbon double bonds were present to react with the bromine 205 What is the molecular weight of a compound that undergoes an aldol self-condensation reaction to result in a β-hydroxy ketone with a molecular weight of 144? A) 70 g/mole B) 72 g/mole C) 74 g/mole D) 76 g/mole 206 The aldol self-condensation of acetone is an equilibrium that favors acetone over its condensation product Which of the following experimental modifications is most likely to shift the position of equilibrium toward Product A? A) Using only a catalytic amount of NaOH B) Using only a catalytic amount of acetone C) Removing Product A as it is formed D) Increasing the reaction temperature to the boiling point of acetone 207 Based ONLY on Observations and only, which of the following compounds could have been Product A? A) B) C) CH2=CHCH2–O–CH2CH2CH3 D) The structure of Product A was further confirmed when treatment with hot sulfuric acid resulted in the corresponding dehydration product, Product B 208 When a drop of Br2 in CCl4 is added to Product B, the resulting solution will be: A) colorless, because Product B does not contain a carbon-carbon double bond B) colorless, because Product B contains a carboncarbon double bond C) red, because Product B does not contain a carboncarbon double bond D) red, because Product B contains a carbon-carbon double bond Sharing or reproducing this material in any form is a violation of the AAMC copyright 72 209 The chemist obtained a proton NMR spectrum of a sample of the isolated Product A If the sample were contaminated with acetone, how many extra signals corresponding to the acetone would be present in the spectrum? A) B) C) D) 210 Which of the following compounds from the passage will give a positive iodoform test? A) Product A only B) Product A and Product B only C) Product A and acetone only D) Product A, Product B, and acetone Sharing or reproducing this material in any form is a violation of the AAMC copyright 73 These questions are not based on a descriptive passage and are independent of each other 211 In eukaryotes, oxidative phosphorylation occurs in the mitochondrion The analogous structure used by bacteria to carry out oxidative phosphorylation is the: A) cell wall B) ribosome C) nuclear membrane D) plasma membrane 212 Nucleosomes typically consist of which of the following? I DNA II Histones III Microtubules 215 Ignoring stereochemistry, how many different tripeptides may exist that contain the same three amino acids as the molecule shown below? A) B) C) D) 216 A drug that binds to tubulin molecules of plant cells and prevents the cells from assembling spindle microtubules would most likely cause the resulting plants or plant cells to have: A) greater genetic variability than the parent plants B) more than two sets of chromosomes C) a stronger cell wall because of excess tubulin D) independent movement because of excess tubulin A) I only B) I and II only C) II and III only D) I, II, and II 213 In which organelle of a eukaryotic cell is the pyrimidine uracil, as part of uridine triphosphate (UTP), incorporated into nucleic acid? A) The nucleus B) The Golgi bodies C) The ribosomes D) The endoplasmic reticulum 214 The enzyme pepsin, which catalyzes the hydrolysis of proteins in the stomach, has a pH optimum of 1.5 Under conditions of excess stomach acidity (pH of 1.0 or less), pepsin catalysis occurs very slowly The most likely reason for this is that below a pH of 1.0: A) pepsin is feedback-inhibited B) pepsin synthesis is reduced C) the peptide bonds in pepsin are more stable D) the three-dimensional structure of pepsin is changed Sharing or reproducing this material in any form is a violation of the AAMC copyright 74 MCAT Practice Test 3R Answer Sheet Physical Sciences (A) (B) (C) (A) (B) (C) (A) (B) (C) (A) (B) (C) (A) (B) (C) (A) (B) (C) (A) (B) (C) (A) (B) (C) (A) (B) (C) 10 (A) (B) (C) 11 (A) (B) (C) 12 (A) (B) (C) 13 (A) (B) (C) 14 (A) (B) (C) 15 (A) (B) (C) 16 (A) (B) (C) 17 (A) (B) (C) 18 (A) (B) (C) 19 (A) (B) (C) 20 (A) (B) (C) 21 (A) (B) (C) 22 (A) (B) (C) 23 (A) (B) (C) 24 (A) (B) (C) 25 (A) (B) (C) 26 (A) (B) (C) 27 (A) (B) (C) 28 (A) (B) (C) 29 (A) (B) (C) 30 (A) (B) (C) 31 (A) (B) (C) 32 (A) (B) (C) 33 (A) (B) (C) 34 (A) (B) (C) 35 (A) (B) (C) 36 (A) (B) (C) 37 (A) (B) (C) 38 (A) (B) (C) 39 (A) (B) (C) 40 (A) (B) (C) 41 (A) (B) (C) 42 (A) (B) (C) 43 (A) (B) (C) 44 (A) (B) (C) 45 (A) (B) (C) 46 (A) (B) (C) 47 (A) (B) (C) 48 (A) (B) (C) 49 (A) (B) (C) 50 (A) (B) (C) 51 (A) (B) (C) 52 (A) (B) (C) 53 (A) (B) (C) 54 (A) (B) (C) 55 (A) (B) (C) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) Verbal Reasoning 78 (A) (B) (C) (D) 79 (A) (B) (C) (D) 80 (A) (B) (C) (D) 81 (A) (B) (C) (D) 82 (A) (B) (C) (D) 83 (A) (B) (C) (D) 84 (A) (B) (C) (D) 85 (A) (B) (C) (D) 86 (A) (B) (C) (D) 87 (A) (B) (C) (D) 88 (A) (B) (C) (D) 89 (A) (B) (C) (D) 90 (A) (B) (C) (D) 91 (A) (B) (C) (D) 92 (A) (B) (C) (D) 93 (A) (B) (C) (D) 94 (A) (B) (C) (D) 95 (A) (B) (C) (D) 96 (A) (B) (C) (D) 97 (A) (B) (C) (D) 98 (A) (B) (C) (D) 99 (A) (B) (C) (D) 100 (A) (B) (C) (D) 101 (A) (B) (C) (D) 102 (A) (B) (C) (D) 103 (A) (B) (C) (D) 104 (A) (B) (C) (D) 105 (A) (B) (C) (D) 106 (A) (B) (C) (D) 107 (A) (B) (C) (D) 108 (A) (B) (C) (D) 109 (A) (B) (C) (D) 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) Writing Sample 138 139 Biological Sciences 140 (A) (B) (C) (D) 141 (A) (B) (C) (D) 142 (A) (B) (C) (D) 143 (A) (B) (C) (D) 144 (A) (B) (C) (D) 145 (A) (B) (C) (D) 146 (A) (B) (C) (D) 147 (A) (B) (C) (D) 148 (A) (B) (C) (D) 149 (A) (B) (C) (D) 150 (A) (B) (C) (D) 151 (A) (B) (C) (D) 152 (A) (B) (C) (D) 153 (A) (B) (C) (D) 154 (A) (B) (C) (D) 155 (A) (B) (C) (D) 156 (A) (B) (C) (D) 157 (A) (B) (C) (D) 158 (A) (B) (C) (D) 159 (A) (B) (C) (D) 160 (A) (B) (C) (D) 161 (A) (B) (C) (D) Sharing or reproducing this material in any form is a violation of the AAMC copyright 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (A) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (B) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (C) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) (D) 75 .. .MCAT Practice Test 3R Physical Sciences Time: 100 minutes Questions: 1-77 Most questions in the Physical Sciences test are organized into groups, each containing... account The AAMC and its Section for the MCAT hold the copyrights to the content of this Practice Test Therefore, there can be no sharing or reproduction of materials from the Practice Test in any... account The AAMC and its Section for the MCAT hold the copyrights to the content of this Practice Test Therefore, there can be no sharing or reproduction of materials from the Practice Test in any