mcat full length4

Physical SciencesTime: 100 Minutes

Questions 1–77

DO NOT BEGIN THIS SECTION UNTIL YOU ARE TOLD TO DO SO.

MCAT FL-4 06/27/2003 11:28 AM

PHYSICAL SCIENCES

DIRECTIONS: Most of the questions in the PhysicalSciences test are organized into groups, with adescriptive passage preceding each group of ques-tions. Study the passage, then select the single bestanswer to each question in the group. Some of thequestions are not based on a descriptive passage; youmust also select the best answer to these questions. Ifyou are unsure of the best answer, eliminate thechoices that you know are incorrect, then select ananswer from the choices that remain. Indicate yourselection by blackening the corresponding circle onyour answer sheet. A periodic table is provided belowfor your use with the questions.

PERIODIC TABLE OF THE ELEMENTS

2

1

H

1.0

2

He

4.0

3

Li

6.9

4

Be

9.0

5

B

10.8

6

C

12.0

7

N

14.0

8

O

16.0

9

F

19.0

10

Ne

20.2

11

Na

23.0

12

Mg

24.3

13

Al

27.0

14

Si

28.1

15

P

31.0

16

S

32.1

17

Cl

35.5

18

Ar

39.9

19

K

39.1

20

Ca

40.1

21

Sc

45.0

22

Ti

47.9

23

V

50.9

24

Cr

52.0

25

Mn

54.9

26

Fe

55.8

27

Co

58.9

28

Ni

58.7

29

Cu

63.5

30

Zn

65.4

31

Ga

69.7

32

Ge

72.6

33

As

74.9

34

Se

79.0

35

Br

79.9

36

Kr

83.8

37

Rb

85.5

38

Sr

87.6

39

Y

88.9

40

Zr

91.2

41

Nb

92.9

42

Mo

95.9

43

Tc

(98)

44

Ru

101.1

45

Rh

102.9

46

Pd

106.4

47

Ag

107.9

48

Cd

112.4

49

In

114.8

50

Sn

118.7

51

Sb

121.8

52

Te

127.6

53

I

126.9

54

Xe

131.3

55

Cs

132.9

56

Ba

137.3

57

La *

138.9

72

Hf

178.5

73

Ta

180.9

74

W

183.9

75

Re

186.2

76

Os

190.2

77

Ir

192.2

78

Pt

195.1

79

Au

197.0

80

Hg

200.6

81

Tl

204.4

82

Pb

207.2

83

Bi

209.0

84

Po

(209)

85

At

(210)

86

Rn

(222)

87

Fr

(223)

88

Ra

226.0

89

Ac †

227.0

104

Rf

(261)

105

Ha

(262)

106

Unh

(263)

107

Uns

(262)

108

Uno

(265)

109

Une

(267)

*

58

Ce

140.1

59

Pr

140.9

60

Nd

144.2

61

Pm

(145)

62

Sm

150.4

63

Eu

152.0

64

Gd

157.3

65

Tb

158.9

66

Dy

162.5

67

Ho

164.9

68

Er

167.3

69

Tm

168.9

70

Yb

173.0

71

Lu

175.0

†

90

Th

232.0

91

Pa

(231)

92

U

238.0

93

Np

(237)

94

Pu

(244)

95

Am

(243)

96

Cm

(247)

97

Bk

(247)

98

Cf

(251)

99

Es

(252)

100

Fm

(257)

101

Md

(258)

102

No

(259)

103

Lr

(260)

MCAT FL-4 06/27/2003 11:28 AM

Passage I (Questions 1–7)

The Hubble Space Telescope (HST) is an astronomicalsatellite in low orbit above the earth’s atmosphere. Thetelescope provides the best photometric measurementsever to be achieved from any astronomical image.

Light enters the telescope and is focused by the pri-mary mirror onto the secondary mirror. The secondarymirror then reflects light through a small hole in the pri-mary mirror to the focal plane, which is shared by redi-recting mirrors and electromagnetic measuringinstruments. The redirecting mirrors send light to the guid-ance center and wide-field/planetary camera (Wiff-Pick).The rays of light that are not intercepted by the redirectingmirrors pass on to the instruments: the faint-object camera(FOC), the high-resolution spectrograph (HRS) and thefaint-object spectrograph (FOS).

Figure 1

The primary mirror is approximately spherical and hasa focal length of 58 m and a diameter of 2.4 m. The sec-ondary mirror is flat and .3 m in diameter. The primary andsecondary mirrors cooperatively focus the light at the focalplane. The mirrors are coated with aluminum and magne-sium fluoride, giving them the capability to reflect lightwith wavelengths between about 110 nm and 1 mm.

The HST enables astronomers to capture light fromdistant galaxies. Light emitted from the distant edges ofthe rapidly expanding universe is shifted to greater wave-lengths by a quantity called the red shift (z). The red shiftis expressed as:

z =

Equation 1

where λobs is the wavelength measured by the HST and λemit

is the wavelength emitted by the object.

The red shift is converted into R, the scale factor of theuniverse, using the formula:

R = 1+

1z

Equation 2

The value of R determines how large the universe waswhen it emitted the light. For example, if a galaxy isobserved with a z = 1, then R =

12

. Therefore the universewas one half its present size when the light was emitted.

(Note: c = 3.00 x 108 m•s–1; h = 6.626 x 10–34 J•s)

1. Which of the following phenomena is responsiblefor the red shift?

A. Ionization

B. Reflection

C. Refraction

D. Doppler effect

2. Based on composition analysis, a certain star isexpected to emit light at a λ of 250 nm. The FOSindicates that the star is emitting a λ of 750 nm. Whatwas the relative size of the universe when the lightwas emitted?

A. 31

B. 21

C. 2

D. 3

3. Which of the following ratios represents the scalefactor of the universe?

A. R =

B. R =

C. R =

D. R =

4. The primary mirror can be described as

A. convex, converging

B. convex, diverging

C. concave, converging

D. concave, diverging

1λobs

λemit

λobsλemit

λemitλobs

11 + λobs

λobs - λemitλemit

GuidanceCenter

Wiff-Pick

•FOC

•FOS

•HRS

Primary Mirror Secondary Mirror

*not drawn to scale

3

GO ON TO THE NEXT PAGE.

MCAT FL-4 06/27/2003 11:28 AM

5. Which are the radius of curvature of the primary andsecondary mirrors respectively?

A. 1.2 m; 0.15 m

B. 29 m; 0.15 m

C. 29 m; infinity

D. 116 m; infinity

6. Which of the following electromagnetic waves canthe HST mirrors reflect?

I. Visible

II. IR

III. Microwaves

A. I only

B. II only

C. II and III only

D. I and II only

7. If incoming parallel rays, when reflected by the mir-rors, converge 2 m to the left of the reflective side ofthe primary mirror, what is the approximate distancebetween the two mirrors?

A. 14 m

B. 28 m

C. 58 m

D. 116 m

γ - rays X - rays UV IR Micro-waves

Radio-waves

Visible

1024 1020 1018 1016 1012 1010 108(sec-1)1014 1011

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MCAT FL-4 06/27/2003 11:28 AM

Passage II (Questions 8–13)

A student conducts an experiment comparing differenttechniques for drying coffee. A liter of dilute coffee isbrewed by grinding sumatra beans, adding 1 L of water at100°C, then passing the mixture through filter paper toremove the coffee bean solids. A student divides the coffeeinto two 0.48 L samples and uses different techniques toremove water from the samples.

Experiment 1

Following brewing, sample 1 is quickly placed in a105°C chamber whose temperature and pressure can becarefully controlled. The 5L chamber can be considered anopen system that allows the transfer of mass and energy.With the temperature and pressure (1 atm) of the chamberheld constant, the temperature of the coffee rises and thewater evaporates. When all of the water has evaporated,the dry powder left in the flask is removed. It has a massof 2.11 grams.

Experiment 2

Sample 2 undergoes a process known as freeze drying.The sample is frozen and placed in an identical chamber at-20°C. The pressure in the chamber is then reduced to0.005 atm. With chamber pressure held constant, thechamber temperature is raised to –5°C. The sample isallowed to sublime until only a granular solid remains.

Figure 1 is a phase diagram for water.

Figure 1

8. At any given temperature and pressure, the ∆H ofsublimation for a substance will be:

A. more than its ∆H of vaporization.

B. less than its ∆H of fusion.

C. the same as its ∆H of fusion.

D. the same as its ∆H of vaporization.

9. Consider the frozen sample in Experiment 2. Whenthis sample is placed in the chamber at an initial pres-sure of 1 atm, which of the following phases of wateris the most thermodynamically stable?

A. gas

B. liquid

C. solid

D. plasma

10. Which of the following could be the boiling point andfreezing point of coffee, respectively (273 K = 0°C)?

A. 373K, 273K

B. 398K, 298K

C. 374K, 270K

D. 370K, 276K

11. Freeze drying produces a more aromatic and flavor-ful coffee because the process provides a slower oxi-dation rate, decreased protein denaturation, andreduced transport of volatile flavor and aromaspecies. Which of the following would be expectedto improve the quality of coffee over that producedby Experiment 2?

A. replacing the air in the chamber with helium gasat 0.005 atm

B. changing the final temperature of the chamberto 0°C

C. providing a larger interface area between thesurface of the frozen coffee and the air in thechamber

D. compressing the frozen sample using a pistonmechanism

200 250 300 350 400 450 500 550 600

1000

100

10

1

0.1

0.01

0.001

Liquid H2O

Solid

H2O

Gas H2O

Pres

sure

(at

m)

Temperature (K)

A

650

B

5


MCAT FL-4 06/27/2003 11:28 AM

12. Regulation of the chamber temperature is achievedby increasing or decreasing the flow of liquid nitro-gen (–200°C) or steam (150°C) through pipes aboutthe chamber’s metal walls. Which of the followingcould describe the flow of heat from the sample inExperiment 2?

A. conduction then radiation

B. radiation then conduction

C. radiation then conduction then convection

D. convection then radiation then conduction

13. A glass of pure water at room temperature is placedin the chamber and the pressure is decreased to 0.05atm. A “heat sink” is used to extract heat from thechamber at a constant rate and the temperature of thewater is measured at intervals. Which of the follow-ing plots best indicates the temperature of the waterover time?

A.

B.

C.

D.

Tem

pera

ture

C

Time

0

25

-25

Tem

pera

ture

C

Time

0

25

-25

Tem

pera

ture

CTime

0

25

-25Te

mpe

ratu

re C

Time

0

25

-25

6


MCAT FL-4 06/27/2003 11:28 AM

Passage III (Questions 14–19)

The Michelson interferometer exploits the phe-nomenon of interference between light waves. A simpli-fied schematic of such a device is shown below:

Figure 1

A beam of electromagnetic radiation (usually in eitherthe visible or infrared region) falls upon a beamsplitter.The beamsplitter, which is essentially a mirror that is semi-transparent to the radiation used, causes the beam of radi-ation to be split such that half of the intensity is transmittedwhile the other half is reflected. These two beams thenstrike mirrors M1 and M2, one of which is fixed and theother movable. The beams are reflected back towards thebeamsplitter, where they interfere and are then directedtowards the detector. In the diagram shown above, d1 is thedistance between the beamsplitter and M1, and d2 is thedistance between the beamsplitter and M2. Depending onthe difference between d1 and d2, the two beams may inter-fere either constructively or destructively.

Consider the case where the radiation is monochro-matic (i.e. when it consists of electromagnetic waves of asingle frequency). If d1 is equal to d2, the distance traveledby the two beams of radiation will be identical, and thusthe waves will interfere constructively. However, if thetwo distances differ by an amount x, the lengths of thepaths traveled by the two beams will differ by 2x (since thedistance between the beamsplitter and each mirror is tra-versed twice). Destructive interference occurs when thisdifference of 2x, known as the retardation, causes the twobeams to be 180° out of phase.

As the movable mirror is translated, its distance fromthe beamsplitter increases smoothly, and so does the retar-dation. The intensity of the radiation reaching the detectorwill vary as the interference goes from constructive todestructive and back. The interferogram, a plot of theintensity versus retardation, will exhibit a sinusoidal

shape: It will show a series of maxima and minima (brightand dark fringes) corresponding to constructive anddestructive interferences respectively (Figure 2). The con-dition for constructive interference for the Michelsoninterferometer is:

|d1 – d2| = mλ/2

where m = 0, 1, 2, … and λ is the wavelength of the radi-ation source.

Figure 2

14. If a helium-neon laser is used as the light source (λ = 6328 Å), how far should the movable mirror bedisplaced to move from one bright fringe to the nextone?

A. 3164 Å

B. 6328 Å

C. 9492 Å

D. 12660 Å

15. If the frequency of the monochromatic radiation isincreased (all else being the same), which of the fol-lowing would result?

I. The maximum intensity registered by thedetector would be lower.

II. The minimum intensity registered by thedetector would be lower.

III. More maxima and minima will be encoun-tered for a given distance.

A. I only

B. II only

C. III only

D. II and III only

inte

nsity

retardation

0 λ/2 λ 3λ/20

radiationsource

beamsplitter

M1

M2

detector

d1

d2

7


MCAT FL-4 06/27/2003 11:28 AM

16. If the source radiation consists of light of two distinctwavelengths λ1 and λ2 that are relatively close invalue, which of the following characterizes theappearance of the interferogram?

A. a beat wavelength of |λ1 – λ2|

B. a beat wavelength of |λ1 + λ2|

C. a beat frequency of |λc

1

– λc

2

|

D. a beat frequency of |λc

1

+ λc

2

|

17. One application of the interferometer is the determi-nation of the index of refraction of a gas sample. Ifthe wavelength of light in vacuum is λ0, then howmany wavelengths will fit in a distance d in amedium with an index of refraction of n? (The speedof light in a medium with an index of refraction n isgiven by v = c/n.)

A. nλ0/d

B. nd/λ0

C. λ0/nd

D. d /nλ0

18. If the source radiation consists of a continuous rangeof wavelengths, the resulting interferogram:

A. exhibits maximum constructive interferenceonly when the retardation equals zero.

B. exhibits the same periodicity as the lowestwavelength component of the source radiation.

C. exhibits the same periodicity as the highestwavelength component of the source radiation.

D. exhibits no constructive interference.

19. If the beamsplitter did not split the beam exactly inhalf:

A. constructive interference would have a lowermaximum amplitude.

B. destructive interference would not be total.

C. the arm with the stronger intensity would needto have its distance increased.

D. the arm with the stronger intensity would needto have its distance decreased.

8


MCAT FL-4 06/27/2003 11:28 AM

Passage IV (Questions 20–24)

Chemiluminescence occurs when a chemical reactionproduces an electronically excited species, which thenemits a photon in the visible range as it relaxes to theground electronic state. The following is an example of areaction scheme exhibiting chemiluminescence:

NO + O3 → NO2* + O2

NO2* → NO2 + hν

where the asterisk denotes an excited state. Monitoring theintensity of the luminescence produced in this reactionsequence, for example, offers an accurate and very sensi-tive way of determining the concentration of NO in a sam-ple of air.

Chemiluminescence can also be used as an analyticalmethod in the liquid phase; reactions involving the chemi-luminescent compound luminol are a case in point. Uponoxidation, luminol forms the 3-aminophthalate anionwhich then luminesces in the blue region of the spectrum.

The oxidation reaction of luminol by hydrogen perox-ide requires a catalyst such as peroxidase or Fe2+ ions. Theintensity of the luminescence increases linearly with theconcentration of the catalyst (at least over a certain rangeof concentrations).

The luminol reaction can also be used as the basis foran analytic technique to determine the concentration ofspecies that cause suppression of chemiluminescence.Many organic molecules, for example, complex with metalions. In the luminol reaction, the presence of thesemolecules will make the Fe2+ ions unavailable as catalysts,i.e., the ions are effectively removed from the system. Todetermine the concentration of the organic species, theintensity of the chemiluminescence is first recorded whennone of the organic molecules is present. This establishesa “baseline” signal. Then, the reaction is carried out againin the presence of the organic species, and the intensity isagain recorded. The decrease in intensity is an indicationof the concentration of the organic species.

20. Chemiluminescence of which of the following colorscorresponds to radiation with the highest frequency?

A. Red

B. Yellow

C. Green

D. Violet

21. Upon oxidation to the 3-aminophthalate anion, thenumber of sp2 hybridized carbon atoms in luminol:

A. increases by 2.

B. remains unchanged.

C. decreases by 2.

D. decreases by 4.

22. Not all of the energy of the excited state molecule isnecessarily emitted during luminescence. Moleculescan also undergo “nonradiative relaxation,” in whichpart of the energy is dissipated through collisionswith other molecules. One consequence of this “col-lisional deactivation” channel is that:

A. increasing the total pressure of the systemwould lead to higher frequency luminescencefor a gas-phase reaction.

B. increasing the total pressure of the systemwould lead to higher intensity luminescence fora gas-phase reaction.

C. molecules may luminesce over a range of wave-lengths rather than at a single discrete one.

D. molecules may remain in the excited state andnever luminesce.

23. Which of the following is NOT an acceptable Lewisstructure for NO?

A.

B.

C.

D.

N O

N O

N O

N O

oxidizing system

(catalyst)NH

NH

NH2 O

O

NH2

COO –

COO –

+ hν

luminol

9


MCAT FL-4 06/27/2003 11:28 AM

24. In order to carry out the analysis described in the lastparagraph of the passage, which of the followingconditions needs to be true?

A. The Fe2+ ions should encounter the organicspecies before being introduced into the lumi-nol-peroxide mixture, and the concentration ofthe organic species should be lower than theconcentration of Fe2+.

B. The Fe2+ ions should encounter the organicspecies before being introduced into the lumi-nol-peroxide mixture, and the concentration ofthe organic species should be higher than theconcentration of Fe2+.

C. The Fe2+ ions should encounter the organicspecies after being introduced into the luminol-peroxide mixture, and the concentration of theorganic species should be lower than the con-centration of Fe2+.

D. The Fe2+ ions should encounter the organicspecies after being introduced into the luminol-peroxide mixture, and the concentration of theorganic species should be higher than the con-centration of Fe2+.

10


MCAT FL-4 06/27/2003 11:29 AM

Questions 25 through 29 are NOT based ona descriptive passage.

25. How does the magnitude of the restoring forcechange as the simple pendulum below swings frompositions 1 through 3?

A. increases then decreases

B. decreases then increases

C. remains the same

D. It cannot be predicted.

26. Consider the static pulley system illustrated below.Which of the following would be sufficient informa-tion to determine the mass B? (Assume a frictionlesssystem, g = 10 m/s2)

A. Mass of A and angle θB. Tension T, height h and distance d

C. Height h and angle θD. Angle θ and distance d

27. What physical quantity can be determined by divid-ing Newtons (N) by an amount of mass?

A. Work

B. Energy

C. Velocity

D. Acceleration

28. In which of the following situations will the normalforce on a box be the greatest?

A. When the box is placed in a stationary elevator.

B. When the box is placed in an elevator movingupwards at a constant velocity.

C. When the box is placed in an elevator accelerat-ing downwards.

D. When the box is placed in an elevator accelerat-ing upwards.

BA h

T

d

θ

1

2

3

11


MCAT FL-4 06/27/2003 11:29 AM

29. The following titration curve would be expectedfrom which of the following amino acids?

H2N CH C

CH2

OH

O

N

NH

H2N CH C

CH

OH

O

CH3

CH3

A.

B. D.

H2N CH C

CH2

OH

O

C

O–

O

H2N CH C

CH2

OH

O

CH2

C

O–

O

C.

2

4

6

8

10

1 2 3OH– (equivalents)

pH

12


MCAT FL-4 06/27/2003 11:29 AM

Passage V (Questions 30–34)

A chemist determined the amount of chloride ion in asolid unknown sample by gravimetric precipitation withsilver ion. A 0.2020 g sample of the unknown was dis-solved completely in 100 mL of dilute, aqueous nitric acid.The subsequent addition of 20 mL of 0.20 M aqueous sil-ver nitrate solution resulted in the immediate formation ofa white precipitate.

The solution containing the precipitate was swirled andcooled, then filtered through a sintered glass crucible. Theprecipitate was then washed with cold, dilute nitric acidand dried. The mass of silver chloride recovered was deter-mined to be 0.3485 g.

Reaction 1 describes the solubility of silver chloride inwater at the temperature at which the analysis was done.

AgCl (s) Ag+ (aq) + Cl– (aq) Ksp = 1.56 10–10

Reaction 1

Until it is dried, a silver chloride precipitate is susceptibleto photodecomposition (Reaction 2):

AgCl (s) hv→ Ag (s) +

12

Cl2 (g)

Reaction 2

The further reaction of excess silver ion with dissolvedchlorine gas (Reaction 3) is also a possibility.

3Cl2 (aq) + 5Ag+ (aq) + 3H2O (l)5AgCl (s) + ClO3

– (aq) + 6H+ (aq)

Reaction 3

30. What is the approximate mass percent of chloride ionin the original sample?

A. 34%

B. 43%

C. 58%

D. 85%

31. Which of the following would have the least effecton the accuracy of the results obtained from the anal-ysis described in the passage?

A. prolonged exposure of the precipitate to sun-light

B. filtration and recovery of the precipitate at ele-vated temperatures

C. NaNO3 impurities in the AgNO3 solution

D. washing the precipitate with dilute HCl insteadof HNO3

32. What is the minimum concentration of chloride ionnecessary to induce precipitation upon addition ofthe silver nitrate solution in the procedure outlined inthe passage?

A. 4.68 x 10–9 M

B. 3.12 x 10–11 M

C. 5.20 x 10–12 M

D. 6.24 x 10–12 M

33. The precipitate obtained in another experiment fol-lowing the described procedure was a light violet-gray. A possible explanation for the color is:

A. contamination by nitrate ion due to excessivewashing with nitric acid.

B. higher temperatures leading to an excess of sil-ver ions trapped within the crystal lattice of theprecipitate.

C. the presence of finely divided silver producedby photodecomposition.

D. silver chloride precipitates are violet in color.

34. If the solution containing the silver chloride precipi-tate is to be stored overnight before filtration, whichof the following would be true?

A. The sample must be protected from light toavoid photodecomposition of the precipitate.

B. The extra time will allow for an increase in themass of precipitate formed.

C. Evaporation of the solvent will lead to adecrease in the mass of precipitate recovered.

D. Exposure of the solution to chlorine vapors inthe air will lead to artificially low results.

13


MCAT FL-4 06/27/2003 11:29 AM

Passage VI (Questions 35–39)

A ship is engineered with the ability to right itselfunder severe environmental conditions. When waves andwind cause a ship to tilt, a torque is generated that restoresthe ship to equilibrium. However, if the angle of tilt is toogreat, a ship will overturn and sink.

On calm water, a ship is in rotational equilibrium. Theforces of gravity and buoyancy act along the centerline ofthe ship and are equal in magnitude and opposite in direc-tion. Referring to Figure 1, the buoyant force (Fb) acts at thehydrostatic center (H), which is the center of gravity of thefluid displaced by the ship. The gravitational force (Fg) oper-ates at the center of gravity of the ship (C). When a ship tilts,H shifts to the leaning side (the center of gravity does notshift) and the forces no longer operate along the same axis.The point at which the buoyant force vector intersects thecenterline is called the metacenter (M). The displacementfrom C to M is called the metacentric height (m).

Figure 1

The buoyant force exerts a torque (τ) about the centerof gravity according to the equation:

τ = Fb • m • sin θ

Equation 1

where Fb is the buoyant force, m is the metacentric height,and θ is the angle between the buoyant force vector and themetacentric height. The torque exerted by the buoyantforce is referred to as the restoring torque.

The stability of the ship depends on the magnitude ofthe restoring torque. The restoring torque is proportional tothe width of the ship, because the hydrostatic center getsdisplaced further. The restoring torque is inversely propor-

tional to the height of the ship because the higher center ofgravity decreases the metacentric height.

(Note: Fb = ρgV)

35. More torque is generated when a ship tilts at a greaterangle because:

I. H is displaced further from the centerline

II. a greater θ is generated

III. the buoyant force increases

A. I only

B. II only

C. I and II only

D. I, II and III

36. A ship will overturn when

A. the force of gravity exceeds the buoyant force.

B. the metacentric height becomes negative.

C. the hydrostatic center and center of gravity arenot along the same line.

D. the restoring torque reaches a minimum.

37. Which of the following correctly represents the massof the water displaced by a tilting boat?

A. Fbsi

τn θ

B. gms

τin θ

C.

D. ρgV

38. According to Newton’s third law, for every actionthere is an equal and opposite reaction. Which of thefollowing is the reactive force to gravity on the ship?

A. Restoring torque

B. Buoyant force

C. Gravity on the earth

D. Gravity on the fluid

FbgV

C

Fb

Fg

H

M

m

C

H

Calm Water Rough Water

θ

centerline

x

y

14


MCAT FL-4 06/27/2003 11:29 AM

39. Which of the following represents the componentvector of the force that generates the restoringtorque?

A. A

B. B

C. C

D. D

B

C

D

M

A

θ

15


MCAT FL-4 06/27/2003 11:29 AM

Passage VII (Questions 40–45)

The apparatus for the Joule-Thomson experiment isshown below in Figure 1. Two chambers of gas are sepa-rated by a porous plug. A piston is used to force the gas inchamber 1 at constant pressure P1 through the plug intochamber 2 at constant pressure P2, where P1 > P2. Theentire system is thermally insulated and the plug is alsomade of thermally insulating material. As a result, the pro-cess takes place adiabatically, and each chamber is main-tained at its own constant temperature.

Figure 1

An ideal gas undergoes no temperature change as itmoves into the second chamber. For a real gas, however,internal work is done against the intermolecular forces andso the temperature changes as the gas expands into theother chamber.

In general the expansion of the real gas into the secondchamber may either raise or lower the temperature. Everyreal gas has a characteristic inversion temperature, Tinv.When the temperature is below this inversion temperature,the Joule-Thomson effect causes cooling; when the tem-perature is above the inversion temperature, heatingresults.

If the real gas is adequately described by the van derWaals equation of state, its Tinv can be expressed as

Tinv = R

2a

b

where R is the universal gas constant, and a and b are thevan der Waals constants that appear in the van der Waalsequation of state, which offers a semi-empirical model forthe behavior of real gases:

(P + )(V – nb) = nRT

The van der Waals constants for some gases are givenin Table 1:

Table 1

Gas a b(atm•L2/mol2) (L/mol)

He 0.0341 0.0237

H2 0.244 0.0266

O2 1.36 0.0318

N2 1.39 0.0391

CH4 2.25 0.0428

CO2 3.59 0.0427

HCl 3.67 0.0408

40. Which of the following gases has the highest inver-sion temperature?

A. He

B. H2C. N2D. CH4

41. If the amount of gas that is transferred from chamber1 to chamber 2 does net work upon expansion, whichof the following must be true?

A. T1 > T2B. T1 < T2C. |P1∆V1| > |P2∆V2|

D. |P1∆V1| < |P2∆V2|

42. A real gas is compressed at constant temperaturefrom an initial pressure of P0 and an initial volume ofV0 to a final volume of

12

V0. Its final pressure is:

A. more than 2P0.

B. 2P0.

C. less than 2P0.

D. indeterminate, depending on the precise initialconditions.

an2

V2

porous plug

P1,V1,T1 P2,V2,T2

16


MCAT FL-4 06/27/2003 11:29 AM

43. Which of the following is true about an ideal gas thatundergoes the Joule-Thomson process?

A. It does no net work on the environment.

B. Its entropy decreases.

C. It will be liquefied.

D. Its change in internal energy is of a higher mag-nitude than that of a real gas.

44. Which of the following diagrams best illustrates thepotential energy of interaction between two real gasmolecules as a function of their separation r?

45. Two separate vessels of equal volume are filled withgas at the same temperature and pressure. One vesselcontains neon, while the other contains argon. If thesame amount of heat is added to both vessels at con-stant volume, which of the following is true?(Assume that both gases are ideal.)

A. The two gases will be at the same final temper-ature, but the neon atoms will be moving fasteron average.

B. The two gases will be at the same final temper-ature, and the neon atoms and the argon atomswill be moving at the same average speed.

C. The vessel containing neon will be at a higherfinal temperature.

D. The vessel containing argon will be at a higherfinal temperature.

U

r

A.

U

r

B.

U

r

C.

U

r

D.

17


MCAT FL-4 06/27/2003 11:29 AM

Passage VIII (Questions 46–49)

A long plastic tube is partially filled with water asshown in Figure 1. A spigot at the bottom of the tubeallows water to be drained away, lowering the water level.

Figure 1

A tuning fork of known frequency is struck with a rub-ber mallet and then placed near the open end of the tube,initiating vibrations in the air in the tube. The surface ofthe water always corresponds to a node and the mouth ofthe tube corresponds to an antinode.

While the tuning fork rings near the opening, the spigotis opened to lower the water level. This causes the lengthof the air column to increase, and occasionally it will reacha value at which the frequency of the fundamental, or oneof its overtones, is the same as the frequency of the tuningfork. (See Figure 2.) When this happens, resonance occursand a loud ringing response is heard.

Figure 2

The values of the air column lengths corresponding toresonance are recorded below:

Frequency of Length of air columntuning fork (Hz) at resonance (cm)

256 31.9 ± 0.596.0 ± 0.5

426.7 20.0 ± 0.559.8 ± 0.5

384 21.5 ± 0.566.3 ± 0.5

Table 1

46. In the experiment, which of the following could bethe next resonance value of the length of the air col-umn, using the tuning fork of 426.7 Hz?

A. 80 cm

B. 100 cm

C. 120 cm

D. 160 cm

47. The speed of sound in air decreases as the tempera-ture decreases. If the experiment were conducted at alower temperature:

A. the resonance air column lengths woulddecrease.

B. the resonance air column lengths wouldincrease.

C. the frequency of the standing waves woulddecrease.

D. the frequency of the standing waves wouldincrease.

48. The experiment is performed again using a liquidother than water to partially fill the tube. The resultsof the experiment turn out to be the same as thatrecorded in Table 1. What can we conclude about thatliquid?

A. It has the same density as water.

B. It has the same index of refraction as water.

C. It has the same molecular weight as water.

D. Its properties relative to water cannot be deter-mined.

Fundamental First Overtone

spigot

air column

18


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49. When using the tuning fork of frequency 256 Hz, thespigot is closed at the first resonance so that thelength of the air column remains at 31.9 cm. What isthe next frequency that will resonate at this length?

A. 384 Hz

B. 512 Hz

C. 768 Hz

D. 896 Hz

19


MCAT FL-4 06/27/2003 11:29 AM


50. An engineer designs an underground tunnel with twoventilation pipes as shown below. Pipe A opens to theair at ground level, while Pipe B extends aboveground level and is exposed to air moving at a highervelocity. Which of the following is true? (Assumeconstant air density, P +

12

ρv2 + ρgy = constant)

A. Air will flow from left to right in the tunnel.

B. Air will flow from right to left in the tunnel.

C. The direction of air flow in the tunnel dependson the direction of air flow (wind) in the envi-ronment.

D. Air will flow into the tunnel more rapidly viaPipe B than via Pipe A.

51. Which of the following elements is NOT a metal?

A. Au

B. Na

C. Li

D. S

52. Which of the following can be measured in Joules(J)?

A. Kinetic Energy

B. Velocity

C. Weight

D. Power

53. Which of the following species has the same molec-ular (or ionic) geometry as SO2?

A. CO2B. NO2

-

C. XeF2D. NH3

54. A straight wire is placed above a wire ring and cur-rents flow as shown below. In which of the indicatedregions could the magnetic field be zero?

A. 1 and 2

B. 1 and 3

C. 2 and 4

D. 3 and 4

i i

i

2

3

1

4

Pipe A

Pipe B

Tunnel

20


MCAT FL-4 06/27/2003 11:29 AM

Passage IX (Questions 55–61)

The extreme cost of transporting fuel into space ledresearchers to seek more efficient thrusters for long rangespace missions. The ion propulsion system (IPS) is up to13 times as efficient as traditional chemical thrusters andhas the added advantage of relying on an inert fuel, in con-trast to a chemical engine’s highly combustible fuel.

The Deep Space 1 vehicle, shown in Figure 1, was thefirst to test a xenon IPS. In an IPS, ions of a noble gas areaccelerated by an electrical field and ejected from thethruster at high velocity, sometimes exceeding 30 km/s.Although the thrust produced by the IPS is relatively small(Deep Space 1 can produce 92 mN at maximum thrust),the IPS can operate over a long period of time, allowingthe space vehicle to reach very high speeds.

Figure 1

Xenon gas is injected into a bombardment chamber ata controlled rate. A hollow cathode introduces electronsinto the bombardment chamber. The electrons movetowards the peripheral anode, but their path is made longerby a magnetic field produced by ring magnets about thechamber. This increases the likelihood of collisionsbetween electrons and xenon atoms. Some of these colli-sions are energetic enough to ionize xenon, producing apositively charged xenon ion (Xe+) and another electron(e–). The xenon ion is then accelerated through a potentialof 1315 V and is ejected from the thruster at a high veloc-ity.

In order to produce a neutral ion beam, a separate cath-ode ejects electrons into the stream of xenon ions leavingthe chamber. This prevents the xenon ions from beingattracted back towards the chamber.

Mass of Deep Space 1 = 489.5 kg

(408 kg spacecraft, 81.5 kg xenon)

Mass of electron = 9.11 x 10–31 kg

Charge of electron = 1.60 x 10–19 C

55. Assume that the initial velocity of Deep Space 1 is5,000 km/h. Which of the following indicates thechange in momentum of Deep Space 1 caused by theejection of a mole of xenon ions from the thruster ata velocity Vx?

A. (131.3g)Vx

B.

C. 5,000khm (131.3g - ) Vx

D.

56. Consider what happens if the fuel in Deep Space 1 isreplaced with the nobel gas argon, everything elsebeing kept the same. Compared to those of xenon,which of the following will be true regarding thekinetic energy and momentum, respectively, of anion of argon ejected from the IPS?

A. higher, lower

B. same, lower

C. same, higher

D. lower, same

(131.3g 489.5kg) (5,000 khm)2 131.3g(Vx)2

489.5kg

131.3g489.5 kg

(131.3g)Vx489.5kg

Xe

Xe

e- Xe+

Xe+

Xe+

Xe+

Xe+

Xe+

Xe+

Magnetring

Negativegrid (-225V)

Positivegrid (1090V)

Cathode

Anodee-

Cathode

21


MCAT FL-4 06/27/2003 11:29 AM

57. Which of the following magnetic fields will cause theelectron to move along the path indicated below?

A. C.

B. D.

58. When ion propulsion was invented by Dr. HaroldKaufman in 1959, mercury ions were used instead ofnoble gases. Which of the following is true about theelectrons required to ionize mercury?

A. They are higher energy electrons than those thationize xenon because xenon has a lower ioniza-tion energy.

B. They are higher energy electrons than those thationize xenon because xenon has a lower elec-tron affinity.

C. They are lower energy electrons than those thationize xenon because xenon has a higher ioniza-tion energy.

D. They are lower energy electrons than those thationize xenon because mercury has a higher ion-ization energy.

59. If Deep Space 1 fires its thruster at maximum powerfor 1 second, the space craft’s change in momentumis:

A. (1 s)

9(248

m9N.5 kg)

B. (92 mN)(1 s)

C. (48

992.5m

kNg)2 (1 s)2

D. (48

992.5m

kNg)2 (1 s)

60. Which of the following plots best illustrates thevelocity of Deep Space 1 over time? (Assume thatthe IPS fires continuously at maximum thrust andthat the mass of Deep Space 1 is constant.)

A. C.

B. D.

61. Which of the following best describes what wouldhappen if the exterior neutralizing cathode on theDeep Space 1 IPS failed in midflight?

A. The vehicle would slow down because the neg-ative grid would be accelerated towards the pos-itive ions.

B. The positive acceleration of the vehicle wouldincrease because the xenon ions would repel thepositive grid.

C. The acceleration would decrease because thexenon ions would apply a force that woulddecrease the net force on the vehicle.

D. The vehicle would stop because thrust woulddecrease.

TimeV

eloc

ityTime

Vel

ocity

Time

Vel

ocity

Time

Vel

ocity

CathodeCathode

x x x x

x x x x

x x x x

x x x x

CathodeCathode

e-

Cathode

e-

22


MCAT FL-4 06/27/2003 11:29 AM

Passage X (Questions 62–67)

The Winkler method was developed as a means ofdetermining the amount of oxygen dissolved in water.Several variants of the method exist, all involving the oxi-dation and reduction of manganese-containing com-pounds. Manganese, as a transition metal, can exist in anumber of oxidation states. The standard electrode poten-tials for some of the half-reactions involving manganeseare given below in Table 1.

Half-reaction E° (V)Mn(OH)2 + 2e– → Mn + 2OH– –1.57Mn2+ + 2e– → Mn –1.18Mn2O3 + 3H2O + 2e– → 2Mn(OH)2 + 2OH– –0.234MnO2 + 2H2O + 2e– → Mn(OH)2 + 2OH– –0.0442MnO2 + H2O + 2e– → Mn2O3 + 2OH– 0.146MnO4

2– + e– → MnO43– 0.27

MnO4– + e– → MnO4

2– 0.56MnO4

– + 2H2O + 3e– → MnO2 + 4OH– 0.588MnO4

2– + 2H2O + 2e– → MnO2 + 4OH– 0.60MnO4

3– + 2H2O + e– → MnO2 + 4OH– 0.93Mn3+ + e– → Mn2+ 1.56

Table 1

In one variant of the Winkler method, the first stepinvolves the formation of a precipitate of manganoushydroxide in basic aqueous solution:

MnSO4 + 2KOH → Mn(OH)2 ↓ + K2SO4

Reaction 1

The manganous hydroxide then reacts with the dis-solved oxygen to form a brown precipitate:

2Mn(OH)2 + O2 → 2MnO(OH)2 ↓

Reaction 2

The mixture is then acidified, and upon the addition ofKI forms iodine:

MnO(OH)2 + 2H2SO4 → Mn(SO4)2 + 3H2O

Reaction 3

Mn(SO4)2 + 2KI → MnSO4 + K2SO4 + I2

Reaction 4

The iodine is finally titrated with thiosulfate in thepresence of starch indicator to a clear endpoint:

I2 + 2S2O32– → S4O6 + 2I

–

Reaction 5

62. For which of the following half-reactions should theelectrode potential be expected to increase as the pHof the solution increases?

A. Mn2+ + 2e– → Mn

B. Mn2+ → Mn3+ + e–

C. MnO2 + 2H2O + 2e– → Mn(OH)2 + 2OH–

D. Mn(OH)2 + 2OH– → Mn2O3 + 3H2O + 2e–

63. Which of the following should NOT be a limitingreagent in the series of reactions comprising the Win-kler method?

A. O2B. MnO(OH)2C. Mn(SO4)2D. KI

64. When the endpoint of the titration is reached in theWinkler method, the ratio of the number of moles ofthiosulfate ions used to the number of moles of oxy-gen molecules originally present in the solution is:

A. 1:2

B. 1:1

C. 2:1

D. 4:1

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65. Disproportionation occurs when the same speciesacts as both the reducing agent and the oxidizingagent. Based on the electrode potentials given inTable 1, which of the following disproportionationreactions could be used to construct a galvanic cell?

A. 2MnO43– + 2H2O → MnO4

2– + MnO2 + 4OH–

B. 2Mn2O3 + 2H2O → 2Mn(OH)2 + 2MnO2C. 2Mn(OH)2 → Mn + MnO2 + 2H2O

D. 2Mn2+ → Mn3+ + Mn

66. In the reaction between manganous hydroxide andoxygen, the oxidation state of manganese changes:

A. from +2 to +3.

B. from +3 to +2.

C. from +2 to +4.

D. from +4 to +2.

67. NO2– ions can react with iodide in the following

manner:

2I– + 2NO2– + 4H+ → I2 + N2O2 + 2H2O

If NO2– ions were present in the solution during the

thiosulfate titration, how would the result of the anal-ysis be affected?

A. The concentration of O2 will appear higher thanit actually is.

B. The concentration of O2 will appear lower thanit actually is.

C. The solution will appear clear even before theaddition of any thiosulfate.

D. The result of the analysis is not affected.

24


MCAT FL-4 06/27/2003 11:29 AM

Passage XI (Questions 68–72)

A student connected the following circuit. S1, S2 andS3 are switches that can be closed to make electrical con-nection. The resistors are rated at the following values: R1= R2 = R3 = R6 = 10 Ω, R4 = R5 = 20 Ω. Unless otherwiseindicated, the battery can be assumed to be ideal (no inter-nal resistance).

68. What is the current through the circuit when only S2is connected?

A. 1.5 A

B. 3 A

C. 4 A

D. 6 A

69. The circuit is initially connected via S1 only. Ifanother switch is then closed, the power dissipatedby R1:

A. increases.

B. decreases.

C. remains the same.

D. increases if the switch closed is S2, decreases ifthe switch closed is S3.

70. What is the effective resistance of the circuit when allthree switches are closed?

A. 7.5 ΩB. 15 ΩC. 20 ΩD. 30 Ω

71. An uncharged capacitor is added to the circuit asfollows:

S4 and S3 are then closed, causing the capacitor to becharged. Which of the following statements is cor-rect?

A. The maximum charge stored in the capacitorwould be the same if S3 had remained open.

B. The capacitor would not be charged if S3 hadremained open.

C. The maximum charge stored in the capacitorwould be lower if S3 had remained open.

D. The maximum charge stored in the capacitorwould be higher if S3 had remained open.

72. All three switches are closed. What can we say aboutthe potential difference across R1 if the internal resis-tance of the battery is no longer negligible?

A. The voltage drop across R1 is higher than in theideal case.

B. The voltage drop across R1 is lower than in theideal case.

C. The voltage drop across R1 is the same as in theideal case, but the current through it is higher.

D. The voltage drop across R1 is the same as in theideal case, but the current through it is lower.

S1

S2

S3

R4

R5

R6

R1

R2

R3

120 V

S4

S1

S2

S3

R4

R5

R6

R1

R2

R3

120 V

25


MCAT FL-4 06/27/2003 11:29 AM


73. Which of the following is the electron configurationof Ag?

A. [Ar]5s14d10

B. [Kr]5s24d10

C. [Kr]5s14d10

D. [Kr]4d8

74. The equilibrium constant for a reaction, K, is relatedto the change in entropy (∆S°) and change inenthalpy (∆H°) as follows:

ln K = ∆RS° – ∆

RHT°

The formation of products will always be favoredwhen

A. ∆S° is positive, ∆H° is positive

B. ∆S° is negative, ∆H° is positive

C. ∆S° is positive, ∆H° is negative

D. ∆S° is negative, ∆H° is negative

75. Which of the following changes would NOT increasethe acceleration of a ball down an inclined plane?

A. Increasing the angle of inclination.

B. Decreasing the friction between the ball and theslope with a lubricant.

C. Decreasing the density of the air to decrease airresistance.

D. Increasing the mass of the ball.

76. A marksman fires a bullet of mass M from a height Htowards a target D meters away at an angle Θ to theground and at velocity V. The center of the target isH meters above the ground. Which of the followingMUST be true if the bullet hits the target center?(Assume there is no air resistance).

A. The bullet reaches its maximum height at a

distance of D2

from the target.

B. VHsinΘ = VHcosΘC. The initial velocity of the bullet, V, must be

greater than MgsinΘ.

D. The angle Θ must be less than 45°.

77. The nucleus of the 228U nuclide contains how manyneutrons and protons, respectively?

A. 124, 104

B. 92, 136

C. 136, 92

D. 228, 92

STOP. IF YOU FINISH BEFORE TIME IS CALLED,CHECK YOUR WORK.YOU MAY GO BACK TO ANYQUESTION IN THIS SECTION ONLY.

26

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Verbal ReasoningTime: 85 MinutesQuestions 78–137


MCAT FL-4 06/27/2003 11:29 AM

28



A balance of power arises when a group of neighbor-ing countries enter a state of economic and military equi-librium. In a balance of power system, a nation statecannot violate the independence or the essential rights ofanother without incurring reprisals. Diplomacy and tradein a balance of power is a continuum of action and reac-tion, rather than a series of attempts at independent policy-making. Peace or the safety of an individual nation is lessimportant in a balance of power than the continuingpreservation of the system itself.

What conditions are necessary for a balance of powerto occur? Firstly, states must be aligned in a “state sys-tem.” The states involved must be independent, close inproximity (often possessing shared borders), and nearequals in power. When one state far outstrips its closeneighbors in power, it dictates economic and military pol-icy for the region. When neighbor states are commensu-rate, however, interaction on issues of shared concerncreates a level playing field for determining policy.

A second factor in the formation of a balance of poweris the framework of the system. To maintain an effectivebalance of power, a system must include a minimum ofthree states. A true equilibrium cannot exist between twostates, because one state inevitably gains an ascendancyover the other. A balance of power is also generally char-acterized by a common ground of culture in the state sys-tem. A group of states is more likely to align in acooperative manner if constituent states perceive a degreeof cultural similarity with their neighbors. Added to this,the mechanisms of diplomacy must be in place for a bal-ance of power to thrive: there must be a distribution ofskilled diplomats and economic alliance structures withinthe system. If this apparatus exists, the system will be suf-ficiently flexible to survive short-lived economic fluctua-tions and military antagonisms.

Inherent in this need for a framework system is a thirdprecondition for the evolution of a balance of power sys-tem: rational estimation. Countries involved in a balanceof power must have a rational means of estimating powerwithin the system. For an economic equilibrium to persist,trade between countries must be accompanied by a flowof information; a nation’s economic planning shouldencompass the dynamics of the entire “state system,” inaddition to its own agriculture and industry. A similar dif-fusion of information must occur on national securityissues. This means that the stability of a state systemdepends on the development of sophisticated militaryintelligence agencies.

The importance of military intelligence is perhaps bestillustrated on a smaller scale. Suppose that your neighborhas stolen your lawnmower and you are considering takingretribution by picking a fight with him. For your survivaland for the continued survival of the balance of power inyour neighborhood, you must first be aware of all relevantpersonal defense issues. In particular, it is critical that youfind out whether your neighbor possesses a gun and mightbe likely to use it under such circumstances. Without thegathering and sharing of such information, the balance ofpower in your neighborhood cannot be maintained.

VERBAL REASONING

DIRECTIONS: There are nine passages in this VerbalReasoning Section. Each passage is followed by sev-eral questions. After reading a passage, select the onebest answer to each question. If you are not certain ofan answer, eliminate the alternatives that you know tobe incorrect and then select an answer from theremaining alternatives. Indicate your selection byblackening the corresponding oval on your answerdocument.

5

10

15

20

25

30

35

40

45

50

55

MCAT FL-4 06/27/2003 11:29 AM

78. The bulk of the passage is devoted to:

A. explaining how a particular phenomenonoccurs.

B. advocating a system of international trade.

C. comparing international relations to interper-sonal ones.

D. outlining three distinct systems of government.

79. Suppose that interest rates in a country are adjustedin response to economic conditions of neighboringcountries. This finding would best support theauthor’s view that:

A. Flexibility on interest rates is critical to a coun-try’s economic survival.

B. Countries tend to consult their neighbors oneconomic issues.

C. A country’s economic policy can be influencedby conditions elsewhere.

D. Economic policy is closely linked to militaryintelligence gathering.

80. Which of the following, if true, would help explainwhy a balance of power is generally characterized bya “common ground of culture” (line 26)?

A. Countries with shared borders often have simi-lar cultures.

B. Cultural differences between two nations areoften the source of military conflict.

C. An extremely powerful nation often influencesthe cultures of all nations surrounding it.

D. Economic alliances among a group of nationsare often driven by shared cultural beliefs.

81. The author’s use of the phrase level playing field fordetermining policy (line 19) is probably meant toindicate that in a balance of power:

A. states coordinate policy in a democratic manner.

B. diplomatic initiatives generally work to theadvantage of all member states.

C. each state has some influence on economic andmilitary events.

D. member states form alliances against countriesoutside the balance of power.

82. The passage suggests that in order to participate in abalance of power, a country must:

I. plan its agricultural and industrial develop-ment.

II. possess information on its neighbors’economies.

III. disclose its military secrets to its neigh-bors.

A. II only

B. I and II only

C. I and III only

D. I, II and III

83. The analogy between an international balance ofpower and the interrelations between neighbors isbased on which of the following assumptions?

A. Both neighbors and neighbor states must avoidconflict whenever possible.

B. Power relations between neighbors are depen-dent on similar factors to those between neigh-bor states.

C. A degree of cultural similarity is required forpeaceful coexistence.

D. The use of force for self-preservation is alwaysjustifiable.

84. According to the passage, which of the followingwould be LEAST critical to the survival of a neigh-borhood’s balance of power?

A. An alliance network of a minimum of five ormore neighbors.

B. The presence of a number of skilled negotiators.

C. Information about the location of dangerousweapons.

D. Shared knowledge of neighbors’ typical behav-ior in times of conflict.

29


MCAT FL-4 06/27/2003 11:29 AM


One of the many remarkable properties of water is theunwillingness of bodies of water of substantially differenttemperature to mix together. It is this unwillingness that isresponsible for the formation in freshwater lakes of astratification phenomenon known as the thermocline.Fisheries biologists must take the thermocline intoaccount when determining management strategies for alake’s sport fishery.

Consider the annual temperature fluctuations in a typi-cal deep-water impoundment in the southern UnitedStates. In late winter, usually the end of February or thefirst of March, whatever ice may have previously formedat the surface of the reservoir melts, and the lake’s temper-ature measures a uniform 38-42 degrees. Wave action stirsoxygen into the water at the reservoir’s surface, and thetemperature uniformity allows distribution of this dis-solved oxygen to all depths. With oxygen plentiful, manyof the reservoir’s fish species, both predator and forage,are found throughout the vertical water column.

The windy, sunny days of early spring warm the reser-voir’s surface quickly. As the surface temperatureincreases, that water expands. Because 50-degree water islighter than 40-degree water, a layer of warmer waterdevelops at the surface, resting like a pillow on the mass ofcolder water below. The pillow of surface water increasesin thickness only slowly, as heat is transferred into thedepths by the limited stirring of wave action.

By early summer, a remarkable stratification hasoccurred. A sharp boundary separates two independentbodies of water within the reservoir. The boundary is atemperature gradient that acts as a barricade to prevent anyfurther mixing of oxygenated surface water into the chillydepths. Depending on wind and ambient air temperatures,the water temperature at the surface near the dam on July1 might be 86 degrees, 84 degrees ten feet down, and 82degrees at 20 feet. But at 24 feet, the temperature hasplunged to 65 degrees. That sharp change in temperatureoccurs in a narrow band called the thermocline.

It is not colder water temperatures in the depths thatforce fish and other aquatic life to congregate in the zonebetween the thermocline and the surface during the sum-mer months. Instead, the inability of the two layers ofwater to mix creates a relative absence of oxygen in thelower, colder zone. The absence of oxygen grows morepronounced as summer progresses...

The cold nights of autumn reverse the warming. Some-time in the fall, water at the surface cools to the point thatit is heavier than the water below the thermocline. This ini-tiates a process known as the turnover: A current of coldbut richly oxygenated water plunges to the bottom of thereservoir, forcing stagnant water back to the surface. Thereservoir reaches equilibrium by early winter and remainsthere until the story repeats itself the following spring.

As winter ends, the depths are well-oxygenated. But asthe thermocline sets up in late spring, the supply of oxygento the depths abruptly shuts off. No oxygen can circulatedownward from the surface to replenish the oxygen con-sumed by fish and dying zooplankton. In reservoirs builtwithin the past few years, this process is hastened by theconstant decay of thousands of trees left standing in thelake. Because of the lack of oxygen in the depths, fish areforced to move upward through the water column into therelatively thin layer of warm water at the surface. Soonmost of the reservoir’s volume is virtually devoid of fish.The more shallow the depth at which the thermocline setsup, the more vulnerable the fish population becomes to theincreased angling pressure of the summer vacationmonths.

85. The author refers to the phenomenon known as“turnover” (line 49) primarily in order to:

A. demonstrate an inverse connection betweenwater temperature and dissolved oxygen levels.

B. illustrate the negative effects a thermocline canhave on a deep-water reservoir.

C. identify the conclusion of a reservoir’s seasonalstratification process.

D. suggest that changes in surface temperature ulti-mately have an inconsequential effect on areservoir.

30


5

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15

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86. The author would most likely argue that:

A. the effects of temperature stratification on anindividual reservoir can be predicted.

B. temperature stratification is the primary influ-ence on a lake’s fish populations.

C. the effects of temperature stratification increaseas reservoirs get older.

D. temperature stratification is only a problem indeep-water reservoirs.

87. Which of the following can be most reasonablyinferred from the author’s description of the decay oftrees in the passage?

A. Only in recent years have trees been left stand-ing in reservoirs.

B. Temperature stratification problems can beavoided by removing all trees before a reservoirfills.

C. The decay process consumes large quantities ofoxygen.

D. The rate of a tree’s decay is related to the tree’sdepth in the water.

88. Which of the following statements, if true, wouldmost weaken the author’s contention that the forma-tion of a thermocline leaves game fish more vulnera-ble to angling pressure?

A. Fish feed more frequently in warmer water.

B. Most fresh water anglers prefer to catch fish atmoderate depths.

C. Most people who visit large reservoirs duringthe summer months do not fish.

D. Many anglers prefer to fish during the coolerweather of spring and fall.

89. Given the information in the passage, which of thefollowing fisheries management strategies would theLEAST likely to succeed in maintaining a fish popu-lation in a deep-water reservoir?

A. Stocking a species of fish that will not feed inwater warmer than 65 degrees.

B. Stocking a species of fish whose metabolismslows dramatically in water cooler than 65degrees.

C. Stocking a species of fish that primarily feedson zooplankton.

D. Stocking a species of fish that grows rapidly inwarm water.

90. Which of the following conclusions can be safelydrawn from the information in the passage?

A. Temperature stratification always affects fish-eries adversely.

B. Wind patterns can influence the stratification ofa lake.

C. Fish cannot penetrate the boundary formed bythe thermocline.

D. The thermocline is found at the same depthevery year in a given reservoir.

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MCAT FL-4 06/27/2003 11:29 AM

Passage III (Questions 91-97)

The diversity of moral views has always been an obsta-cle in the search for objective moral principles. This task ishardest when a moral dispute is based upon differences inbasic moral standards. As we look around the world, wefind societies with radically different standards of justice.Since many of these standards of justice conflict with eachother in a fundamental way, they cannot all be correct. Butit is difficult to choose among them without presuming thevalidity of a particular cultural standpoint.

“Deliberative universalism” is a recent school ofthought that attempts to respond to this moral problem.Deliberative universalists argue that since certain moralstandards are shared by all cultures throughout the world,there must be a set of core values that transcend culturaldifferences. For example, an individual traveling aroundthe world might conclude that the freedom to not be tor-tured is a moral belief shared by people everywhere. Butdeliberative universalists also believe that certain valuesthat are widely but not universally shared should also meritconsideration as core human values. Freedom of con-science, for instance, is a belief that is widespread but byno means universal. The belief that an individual has theright to form and express independent opinions on anygiven subject is a central tenet shared by Western democ-racies. And yet our world traveler would find that thisapparently fundamental human value conflicts with thereligious and ideological beliefs held in many of the coun-tries he visited.

How do deliberative universalists account for differ-ences in moral standards? Their response is perhaps bestillustrated in comparison to two popular alternative moraltheories: cultural relativism, in which it might seem thatthere are no objective requirements at all, and comprehen-sive universalism, which holds that there is a single correctanswer to every moral question. Cultural relativists arguethat each society develops its own distinct system of val-ues. To a cultural relativist, the moral integrity of an indi-vidual’s actions can only be assessed in a cultural context.Working on the day of a particular religious holiday, forinstance, is considered morally “wrong” in one country,but not in another. In a purely relativistic universe, noaction can be considered morally wrong from an objectivestandpoint—it can only conflict with the standards set by aparticular culture. The comprehensive universalist main-tains a dogged position at the other end of the spectrum.He argues that a set of objective moral criteria can bedetermined, and that values that conflict with these criteriaare simply wrong.

If cultural relativism and comprehensive universalismare “black and white” approaches to moral theory, deliber-ative universalism is a “grey” position that fits in betweenthese two extremes, incorporating some objective stan-dards, while reserving judgment on such non-universalvalues as freedom of conscience. On the one hand, delib-erative universalists assume that the fact that some moralvalues appear to transcend all cultural barriers must indi-cate that there is a set of innate, universal human values.On the other hand, they reserve the right to debate the mer-its of moral principles that are commonly-held, but notuniversally subscribed to.

One critique of deliberative universalism is that, likethe comprehensive universalism, it is ultimately dogmaticin its assertion of a set of universal values. Conversely,because it narrows the scope of those values that are con-sidered universal, deliberative universalism is also vulner-able to the main charge laid against culturalrelativism—namely that it turns a blind eye to behaviorthat many of us find reprehensible. If certain moral valuestranscend cultures, what follows? The fact that a feature iscommonplace is not itself a reason to support it. Supposethat you are in a world of dictators where all the tyrantshave discovered foolproof methods for retaining power.Then, we could say that certain features are shared by allsocieties, but we would still have reasons to reject thosefeatures.

91. Critics of deliberative universalism might claim that it:

A. presents a dogmatic defense of culturally spe-cific values.

B. incorporates the problems of two extremepositions.

C. offers too broad a conception of universalvalues.

D. ignores the issue of core human rights.

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92. The standards of justice in Country X are radicallydifferent from those in Country Y. The author wouldcite this as evidence of:

A. the need for cultural relativism.

B. the failure of deliberative universalism.

C. the obstacle to finding objective morals.

D. the key to comprehensive universalism.

93. According to the passage, a “purely relativistic uni-verse” (line 41) would be one in which:

A. There would be no religious holidays.

B. Working on religious holidays would be out-lawed.

C. The government would guarantee freedom ofreligion.

D. Working on a religious holiday would never beobjectively wrong.

94. If a deliberative universalist were to speak before atribunal on human rights he would most likely:

A. stress that the majority should not determinewhat is right for the minority.

B. argue that each society must decide its ownmoral principles.

C. emphasize that values which are not universallyshared can be debated.

D. call for the elimination of “grey areas” causedby moral relativism.

95. The author uses the hypothetical example of “a worldof dictators” (line 71) in order to:

A. illustrate a flaw in deliberative universalism.

B. indicate an obstacle in the search for moral prin-ciples.

C. point out the innate desire for power in humanbeings.

D. argue that deliberative universalism is the mostpractical moral theory.

96. Which of the following most parallels the author’scritique of basing universal moral principles on prac-tices which are common to most cultures?

A. Tyrannical societies will always exist despiteuniversal principles.

B. Moral individuals must resist the immoral con-sensus of a majority.

C. Universal law should be based on formal princi-ples rather than social practice.

D. The fact that something is universally practiceddoes not make it universally acceptable.

97. According to the passage, a deliberative universalistrecognizes two main categories of moral value:

A. legal versus social

B. universal versus debatable

C. cultural versus historical

D. innate versus transcendent

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MCAT FL-4 06/27/2003 11:29 AM

Passage IV (Questions 98-103)

The art of music, performed at the highest level ofartistry, utterly defies our attempts to describe it. Our reac-tion on leaving a satisfying concert is one of wonder, andour attempts to discuss the experience suggest that we arepowerless to penetrate its mysteries; a symphony is breath-taking, a cadenza is dazzling, and a guitar solo is awesome.And yet, the fact that music is sublime continues to inspirepeople to write about it. Nevertheless, our biggest obstacleto understanding music is that our interpretation of it mustbe mediated by language. To discuss music, we must trans-late it, form and function, into a crude system of words andphrases, nouns and adjectives, and lose its ineffableessence in the process.

What is lost in the translation from the intensity of per-formance to the printed page is the meaning of the musicalexperience. Music is above all an act of communication: ituses musical form to convey complex emotional state-ments. The haunting beauty of jazz trumpeter Miles Davis’work, for instance, cannot be explained in technical termsalone. Every phrase that he recorded can be analyzed interms of its pitch, tone quality, harmonic and rhythmicfoundation. And yet what he is remembered for has little todo with his undoubted command of his craft. He is vener-ated for his ability to search inside, tap the emotional coreof his own experience, and express it in music. It is symp-tomatic of twentieth century art that such a sensitive,almost dangerously introspective musician is laudedthroughout the world for his understanding of the humancondition.

The problem in writing about music is our failure tounite our analysis and our appreciation of it. Two quiteseparate discourses dominate the field of music criticism.On the one hand, the academic study of music presents ascientific approach, in which musical works are analyzedin terms of pitch, rhythm, harmony and melodic develop-ment, and related to other works of a similar type or genre.The academic approach concentrates on the quantifiableaspects of music, resolutely shutting out the murky, quali-tative world of interpretation. At the other end of the spec-trum is the discourse of music journalism, which focusesprimarily on the subjective response of the listener. Oftendeficient in technical analysis, journalistic discourse ismore representative of the average listener’s experience ofmusic than its academic counterpart. Music is a magic art;on hearing a Mahler Adagietto, most of us would find iteasy to describe our emotional response, but difficult toidentify its exact cause.

One can see how a purely academic approach canresult in a travesty of the musical experience. Consider ananalysis of The Beatles’ early work that compared thestructure of their songs to those of other groups at the time.Such scholarship would serve to clarify Lennon andMcCartney’s development as composers, and perhaps helpto identify their influences. But without mentioning TheBeatles’ effect on audiences, this redoubtable study wouldfail to address the factors that made this phase in thegroup’s development significant. Less obvious are the pit-falls of the journalistic endeavor. Caught up in describingthe listener’s experience, the music critic often does a dis-service to the composer or musician by pre-forming hisjudgments or not paying sufficient attention to the perfor-mance at hand. Worse still, artistic standards suffer whencriticism is not rooted in some technical analysis of music.Audiences need to understand that a great work or a greatperformance is not simply a matter of each listener’s judg-ment: it is the result of inspirational handling of musicalstructure or instrumental technique.

98. Which of the following statements from elsewhere inthe author’s writing would be most relevant to thefirst paragraph of the passage?

A. “Musicians and writers must first master therules of their craft before they can transcendthose rules.”

B. “The effect of music is as easy to describe accu-rately as the taste of a particular wine.”

C. “A virtuoso performance gives the audience aninsight into the musician’s inner experience.”

D. “Counterpoint is best understood as a dialoguebetween two musical parts.”

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99. The passage suggests that to fully understand the“haunting beauty” of Miles Davis’ music, listenersshould:

I. examine his use of harmony and rhythm.

II. assess its emotional impact on audiences.

III. consider the factors behind his continuingpopularity.

A. I only

B. I and II only

C. II and III only

D. I, II and III

100. The author’s argument that academic discourse canbe a travesty of the musical experience is based onthe assumption that:

A. a composer’s influences have no effect on thepopularity of his music.

B. a critic should assess both the objective and sub-jective aspects of a composer’s work.

C. only those who witness a live performance arequalified to criticize it.

D. music criticism should restrict its scrutiny tolegitimate composers.

101. According to the passage, some degree of technicalanalysis is necessary in music criticism so thataudiences:

A. can incorporate expert opinions into their dis-cussions of music.

B. are not influenced by subjective judgments inevaluating a work or performance.

C. are able to distinguish between an inspired per-formance and a mechanical one.

D. can better comprehend the technical basis of anexcellent performance.

102. The passage suggests which of the following aboutThe Beatles and their early work?

A. The classical orientation of their early work hada profound influence on audiences.

B. Most appraisals of their early work have beenacademic rather than journalistic.

C. The musical influences on Lennon and McCart-ney were not the most significant influence onthe early phase of the Beatles’ development.

D. The music created by Lennon and McCartneywas more structurally complex than that ofother groups at the time.

103. According to the passage, an academic scholar wouldmost likely object to an article by a music journaliston which of the following grounds?

A. The article draws conclusions that cannot beobjectively verified.

B. The article fails to put the performance of musicin a broader social context.

C. The article does not represent the average lis-tener’s experience of music.

D. The article requires from its readers a technicalunderstanding of music.

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MCAT FL-4 06/27/2003 11:29 AM

Passage V (Questions 104-109)

When Alfred Wegener first published the continentaldrift hypothesis in 1912, his novel explanation for why thecontinents seem to fit together like pieces of a jigsaw puz-zle drew explosive criticism from many geologists. It wasnot until the 1960s that a growing tide of evidence for con-tinental drift produced a general change of attitude withinthe discipline.

For at least 300 years, people had noticed that thebulge along the eastern edge of South America fits remark-ably well into the bight of Africa; Francis Bacon suggestedin 1620 that the fit could not be accidental. Several 19th-century scientists offered explanations for the fit; theseexplanations included most notably the contracting-Earthhypothesis of Austrian geologist Eduard Seuss and thelunar hypothesis of English physicist Osmond Fisher.(Fisher argued that the oceans were created when thenewly formed Earth flung off the Moon.) Wegener’s expla-nation was far more comprehensive than any of the earlierhypotheses offered by his predecessors, and it paved theway for the modern theory of plate tectonics...

Wegener used gravity measurements and the observa-tion that the surface of the Earth generally consists of twolevels–the surface of the continents and the bottom of theoceans–to deduce that the continents are composed oflighter rock than the basalt that lies beneath the oceanfloors. The continents, he suggested, float on the denserlayer of basalt like icebergs on water. Wegener’s early crit-ics excoriated him for not proposing a mechanism for pro-pelling the continental “icebergs” through solid basalt,although now there is some theoretical basis for thinkingthat convection might drive the process. Wegener did notlive long enough to find the clear and convincing evidencehis revolutionary hypothesis required, but since his deathin 1930, geologists have learned much that supportsWegener’s earth-shattering idea.

Belts of complimentary rock formations found alongthe African and South American shorelines of the AtlanticOcean make a strong argument for continental drift. In oneextended experiment, geochronologists used both thepotassium-argon and the rubidium-strontium radioactivedating methods to determine the age of a distinctive layerof crystalline basement rock in Ghana. The scientists thenpredicted where the same rock layer would be found at theedge of the South American continent if the two continentshad indeed been contiguous. By sampling and dating rocksin northeastern Brazil, the scientists demonstrated that thelayer does occur in its predicted location. Another belt oftwo-billion-year-old rock that abruptly ends at the edge ofthe West African continental mass and begins again at the

expected location along the coast of South America addsadditional proof that the two continents once formed partof a larger land mass.

The fossil record also contains evidence that Africaand South America were formerly connected. Large bodiesof water act as barriers to the migration of many types ofanimals, as evidenced by the unique fauna of the Galapa-gos Islands. Yet the fossils of identical species of plantsand animals are found on both sides of the southernAtlantic Ocean. The remains of Mesosaurus, a small rep-tile of the Permian that lived in shallow, brackish swamps,are found in only two locations–in the Early PermianDwyka Formation in South Africa and in the Irarare For-mation in Brazil. The rock formations are the same age, aresimilar in composition, and lie directly across the oceanfrom each other. Additionally, the fossil remains of a four-foot-long amphibian from the Triassic have beenunearthed in Africa, South America, and Antarctica, froma layer of rock common to all three continents. These andother fossil discoveries strengthen the likelihood of conti-nental drift.

104. Which of the following pieces of evidence, if true,would most seriously weaken the argument thatSouth Africa and South America were once part of alarger continent?

A. In South America, rock deposits that formed rel-atively recently differ significantly from SouthAfrican rock deposits that formed relativelyrecently.

B. A certain species of modern bird flourishes onlyin South Africa and northern Europe.

C. The distinctive layer of crystalline rock that wassampled in Ghana is found at the same positionin the bedrock all around the world.

D. South America does not share common rockformations with Europe or Asia.

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105. According to the passage, the continental-drifthypothesis was originally:

A. a modification of an earlier hypothesis about thecontracting Earth.

B. rejected by most geologists because it failed toexplain the origin of the Moon.

C. Wegener’s attempt to explain why South Amer-ica and Africa share common rock formationsand fossils.

D. relatively detailed but lacking in supportingevidence.

106. The author’s conclusion about the two-billion-year-old rock formations in Africa and South Americaimplies which of the following?

A. The rock formations would not be in their cur-rent locations if the continents had never beenconnected.

B. The rock formations were on the surface at thetime the continents broke apart.

C. The rock formations would be much younger ifthe continents had never been connected.

D. The rock formations must contain fossils com-mon to both Africa and South America.

107. The conclusion that belts of complimentary rock for-mations are evidence for continental drift presup-poses which of the following?

A. Crystalline basement rock cannot be created inthe absence of continental drift.

B. There was no intervening land mass that sank tothe level of the ocean floor.

C. The continents must have separated about 2 bil-lion years ago.

D. These rock formations can be found at no otherlocations on Earth.

108. With which of the following statements about thecontracting-Earth hypothesis of Eduard Seuss wouldthe author most probably agree?

A. The contracting-Earth hypothesis more effec-tively explains the complimentary shapes ofSouth America and Africa than does the lunarhypothesis.

B. The contracting-Earth hypothesis was more lim-ited in scope than was the continental drifthypothesis.

C. The contracting-Earth hypothesis provided auseful theoretical framework for Wegener’scontinental drift hypothesis.

D. Most scientists who criticized the continentaldrift hypothesis preferred the contracting-Earthhypothesis.

109. If true, which of the following most weakensWegener’s claim that continents float on a denserlayer of basalt like icebergs on water?

A. The density of basalt removed from the oceanfloor is greater than that of most rocks found onthe surface of North America.

B. Samples of Moon rock are the same density ascontinental rock on Earth.

C. The continents extend below the basalt of theocean floors.

D. The density of continental rock varies fromlocation to location.

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MCAT FL-4 06/27/2003 11:29 AM

Passage VI (Questions 110-116)

The social movements which have emerged in the U.S.and Western Europe since the late 1960’s differ distinctlyfrom political movements of the early 20th century. Dif-ferences can be characterized in terms of: membership,issues, values, and methods of action used to achieve polit-ical ends.

A current hypothesis about the post-1960’s socialmovements proposes the following: class membership inthese new movements tends to be more diverse than in theearlier movements; political issues tend to focus more onpersonal freedom as opposed to improved social status;values tend to be less revolutionary and more in accordwith dominant culture; and methods of action tend to beoutside of existing political structures as opposed towithin.

While pre-1960’s social movements were generallycomprised of same class members with similar institu-tional interests, the new social movements consist of mem-bers of various classes whose political affinities cut acrossparty and class lines. In U.S. politics, the 1960’s CivilRights movement included a diverse mixture of middleclass, working class, and ruling class elements, while thetrade-union movements of the 1930’s featured fairlyhomogenous class affiliations.

The central issues for early 20th century social move-ments were economic, including economic stability, equi-table distribution of wealth, and security of social status,whereas post-1960’s social movements have focused on avariety of issues such as gender and racial equality, envi-ronmental health, and nuclear disarmament. Many of thenew social movements have rejected the older movements’political methods of collective bargaining and party com-petition. Instead, the new groups operate through a highlydecentralized system of internal organization, pursuingnon-institutional means of political action such as demon-strations and protests.

This analysis of new social movements in the U.S. andWestern Europe can be used to examine political action innon-Western cultures, such as China. The pro-democracydemonstrations in Tiananmen Square in 1989 fit theparadigm for new social movements in some ways, but notin others. Membership in the movement was not organizedaround discreet class groupings, but came out of a periph-eral social grouping of university students...

To some extent, the relevant issues of the Chinesemovement resemble the model of the older social move-ments in the West. The students’ list of demands included:

increased funding for education, freedom of the press, anda crackdown on government corruption. This focus on eco-nomic and human rights issues–as opposed to an emphasison the newer categorizations of race and gender–moreclosely mimics the older model of early 20th centurysocial movements...

At the same time, the Chinese case confirms thehypothesis of new social movements in terms of its under-lying values. Values in the post-1960’s social movementsof the West were in sync with the values of the dominantculture. Hence the rhetoric of these new social movementsoften critiques the dominant institutions for reneging onpromises or violating agreed upon standards of justice .Martin Luther King’s metaphor of the “bad check” orpromissory note in the “I Have a Dream Speech” is a goodexample of this...

The Chinese movement strongly upheld values whichwere promoted by the Chinese government as well: theChinese government certainly supported the idea of the“dictatorship of democracy” through official speeches andin the Chinese constitution. But other values of the studentmovement fall between the old and new paradigms. TheChinese student movement advocated neither a completeoverhaul of the existing political structure nor an individu-alized system of personal freedom along gender, race, orclass lines. The Chinese case thus presents several anoma-lies to the hypothesis of new social movements based onthe U.S. and Western European model.

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110. Which of the following best describes the structure ofthis passage?

A. The U.S. Civil Rights movement is contrastedwith the Chinese pro-democracy movement.

B. The values of Western and Eastern social move-ments are compared.

C. The characteristics of pre- and post-1960’smovements are contrasted and the Chinesemovement is presented as an example of the for-mer type.

D. A hypothesis is presented about social move-ments in the West, and the Chinese pro-democ-racy movement is examined in relation to thattheory.

111. According to the passage, the class-based move-ments of the 1930’s which relied upon collective bar-gaining and party politics to bring about socialchange were:

A. highly decentralized in their means of politicalaction.

B. similar to the Chinese movement in terms of tra-ditional values.

C. typical of pre-1960’s movements in terms ofmembership and methods.

D. flawed by their reliance on collective bargaining.

112. The “bad check” example (line 61) from MartinLuther King’s “I Have a Dream” speech is used tosupport the claim that late 1960’s social movements:

A. were generally concerned with economic issues.

B. challenged the racism of dominant culture.

C. were based on dominant culture values.

D. failed in their attempts to achieve racial equality.

113. According to the passage, all of the following arecharacteristics of the Chinese pro-democracy move-ment EXCEPT:

A. its membership was class-based.

B. it raised economic issues.

C. its values reflected dominant culture.

D. it opposed censorship of the media.

114. Which of the following questions are answered in thepassage?

I. How have social movements changed overtime?

II. How do social movements differ acrosscultures?

III. Why are there differences between socialmovements?

A. I only

B. I & II only

C. III only

D. I, II, & III

115. The author most likely calls the classification of newsocial movements a hypothesis because:

A. it is an untested theory which must be tested bythe Chinese case.

B. it is based on a series of hypothetical situations.

C. it is a prediction based on prior patterns, butneeds to be tested in a number of social settingssuch as China.

D. it can never be objectively proven, but providesthe best prediction of what might happen.

116. Suppose that all people over 65 created a socialmovement whose method of action was to form apolitical party. What can be concluded based on theinformation in the passage?

A. This movement resembles pre-1960’s move-ments in terms of membership, but not methods.

B. This movement resembles post-1960’s move-ments in terms of values.

C. This movement has elements of both pre- andpost-1960’s movements.

D. This movement resembles the Chinese pro-democracy movement in all respects.

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MCAT FL-4 06/27/2003 11:29 AM

Passage VII (Questions 117-124)

I do not believe that literary studies as such have afuture, but this does not mean that literary criticism willdie. As a branch of literature, criticism will survive, butprobably not in our teaching institutions. The study ofWestern literature will also continue, but on the muchmore modest scale of our current Classics departments.What are now called “Departments of English” will berenamed departments of “Cultural Studies” where Batmancomics, Mormon theme parks, television, movies, androck will replace Chaucer, Shakespeare, Milton,Wordsworth, and Wallace Stevens. Major, once-elitist uni-versities and colleges will still offer a few courses inShakespeare, Milton, and their peers, but these will betaught by departments of three or four scholars, equivalentto teachers of ancient Greek and Latin. This developmenthardly need be deplored; only a few handfuls of studentsnow enter Yale with an authentic passion for reading. Youcannot teach someone to love great poetry if they come toyou without such love. How can you teach solitude? Realreading is a lonely activity and does not teach anyone tobecome a better citizen. Perhaps the ages of reading - Aris-tocratic, Democratic, Chaotic - now reach terminus, andthe reborn Theocratic era will be almost wholly an oral andvisual culture...

...The teaching of poems, plays, stories, and novels isnow supplanted by cheer leading for various social andpolitical crusades. Or else, the artifacts of popular culturereplace the difficult artifices of great writers as the mate-rial for instruction. It is not “literature” that needs to beredefined; if you can’t recognize it when you read it, thenno one can ever help you to know it or love it better. “Aculture of universal access” is offered by post-Marxist ide-alists as the solution to “crisis,” but how can Paradise Lostor Faust, Part Two ever lend themselves to universalaccess? The strongest poetry is cognitively and imagina-tively too difficult to be read deeply by more than a rela-tive few of any social class, gender, race, or ethnic origin.

When I was a boy, Shakespeare’s Julius Caesar,almost universally part of the school curriculum, was aneminently sensible introduction to Shakespearean tragedy.Teachers now tell me of many schools where the play canno longer be read through, since students find it beyondtheir attention spans. In two places reported to me, themaking of cardboard shields and swords has replaced thereading and discussion of the play. No socializing of themeans of production and consumption of literature canovercome such debasement of early education. The moral-ity of scholarship, as currently practiced, is to encourageeveryone to replace difficult pleasures with universallyaccessible pleasures precisely because they are easier.

Trotsky urged his fellow Marxists to read Dante, buthe would find no welcome in our current universities...

...Precisely why students of literature have becomeamateur political scientists, uninformed sociologists,incompetent anthropologists, mediocre philosophers, andover determined cultural historians, while a puzzling mat-ter, is not beyond all conjecture. They resent literature, orare ashamed of it, or are just not all that fond of reading it.Reading a poem or a novel or a Shakespearean tragedy isfor them an exercise in contextualization, but not in amerely reasonable sense of finding adequate backgrounds.The contexts, however chosen, are assigned more forceand value than the poem by Milton, the novel by Dickens,or Macbeth. I am not at all certain what the metaphor of“social energies” stands or substitutes for, but, like theFreudian drives, such energies cannot write or read orindeed do anything at all. Libido is a myth, and so are“social energies.” Shakespeare, scandalously facile, wasan actual person who contrived to write Hamlet and KingLear. That scandal is unacceptable to what now passes forliterary theory.

Either there were aesthetic values, or there are only theoverdeterminations of race, class and gender. You mustchoose, for if you believe that all value ascribed to poems,or plays or novels and stories is only a mystification in theservice of the ruling class, then why should you read at allrather than go forth to serve the desperate needs of theexploited classes? The idea that you benefit the insultedand injured by reading someone of their own origins ratherthan reading Shakespeare is one of the oddest illusionsever promoted by or in our schools.

The deepest truth about secular canon-formation is thatit is performed by neither critics nor academies, let alonepoliticians. Writers, artists, composers themselves deter-mine canons, by bridging between strong precursors andstrong successors.

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117. With which of the following statements is the authormost likely to agree?

A. Literature should challenge the reader tobecome more sensitive to those from anotherclass or race.

B. Literature should be morally edifying, even if itmeans offending members of certain minoritygroups.

C. Literature that is worthwhile often can only beappreciated by a few.

D. Contextualization is an extraneous and mis-guided process when approaching literature.

118. The author claims that Trotsky would “find no wel-come in our current universities” because:

A. the post-Marxist approach of making cultureuniversally accessible is not feasible in therealm of literature.

B. literature that challenges its readers is not infavor in current academia.

C. literature departments are concerned only withthe most fashionable trend in literary theory andMarxism has now been totally discredited.

D. the works of Dante are a poor substitute for thetragedies of Shakespeare.

119. Which of the following, if true, would weaken theauthor’s contention that the study of literature isdeclining?

A. Many students have been able to apply thethemes from works of literature written by theoppressed to solve today’s social and politicalproblems.

B. Some universities, in response to students’desires, have had to redefine the curriculumused by their literature departments.

C. More and more students are interested in pursu-ing a degree in literature, thus necessitating theincrease in the number of classes offered.

D. Because of student interest, universities haveadded courses that focus on the close reading ofShakespeare and Milton.

120. Which of the following would be most heartening tothe author if it were to occur?

A. The compilation by English professors of adefinitive list of works of literature that everystudent should read as part of the canon.

B. A community service requirement in the cur-riculum.

C. Revision of the requirements for a degree inEnglish that would ensure that students becomeknowledgeable in political science, sociologyand anthropology.

D. A revival of genuine interest in reading amongstudents.

121. The author cites the anecdote about Julius Caesar to:

A. investigate why reading is no longer fashionableamong students.

B. illustrate that we no longer challenge our stu-dents with literature.

C. expose how current scholarship has abandonedmorality.

D. give an example of how literary study hasdegenerated into cultural study.

122. The author claims that the dwindling of “Depart-ments of English” in the future is a development that“hardly need be deplored” (line 16) because:

A. even now English departments are hardly recog-nizable as such.

B. it is part of a natural cycle that written literaturesgive way to oral ones.

C. there will always be individuals with a strongenough passion for reading to sustain the tradi-tion.

D. this will ensure that the institutions for higherlearning become more egalitarian than elitist.

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MCAT FL-4 06/27/2003 11:29 AM

123. What is the “scandal” that the author refers to in line70?

A. That creators of literature are individuals ratherthan confluences of social forces

B. That literature departments would think of sub-stituting Batman comics for the works of writerslike Chaucer

C. The imminent languishing of English depart-ments in universities

D. The view held implicitly by some that “socialenergies” are what create literature

124. The author predicts that in the future, reading will:

A. experience a rebirth as more people realize thatclassic literature needs to be appreciated for itsaesthetic value.

B. be surpassed by media that stimulate the partic-ipant through oral and visual cues.

C. become more integral in the moral restructuringof society.

D. become more accessible as the world becomes“smaller” because of advances in communica-tion and technology.

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MCAT FL-4 06/27/2003 11:30 AM

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MCAT FL-4 06/27/2003 11:30 AM

Passage VIII (Questions 125-130)

Contamination is the unintended presence of harmfulsubstances or organisms in food. While it is true that recentscientific advances have resulted in safer foods, bettermethods of preservation, and improved storage practices,it is still necessary to guard against practices that canincrease the likelihood of food contamination. Becausefoodborne illness poses a potentially serious threat to pub-lic health, preventing contamination of safe food needs tobe a prime objective of every foodservice manager.

A foodservice manager must possess accurate informa-tion on the different hazards associated with the contami-nation of food in the event that a foodborne illness crisisdoes arise. A full understanding of the biological, chemi-cal, and physical hazards allows the foodservice managerto implement the control measures necessary to minimizethe health risks associated with food, and thus to decreasethe possibility of contamination.

The most serious risk associated with food is the bio-logical hazard. Biological hazards are dangers to foodfrom pathogenic (disease-causing) micro-organisms, suchas bacteria, viruses, parasites, and fungi, and from toxinsthat occur in certain plants and fish. When biological haz-ards result in foodborne illnesses, these illnesses are gen-erally classified as either infections or intoxications. Afoodborne infection is a disease that results from eatingfood containing living harmful micro-organisms. One ofthe most frequently reported diseases of this type isSalmonellosis, which results from the consumption of foodcontaminated with live pathogenic Salmonella.

The other major form of biologically induced food-borne illness is the foodborne intoxication, which resultswhen toxins, or poisons, from bacterial or mold growth arepresent in ingested food and cause illness in the host (thehuman body). These toxins are generally odorless andtasteless, and are capable of causing disease even after themicro-organisms have been killed. Staphylococcus foodintoxication is one of the most common types of foodborneillness reported in the United States.

In addition to the biological hazard, food is vulnerableto chemical and physical hazards as well that could lead tofoodborne illness. A chemical hazard is the danger posedby chemical substances contaminating food all along thefood chain. For example, pesticides spread over the graz-ing area of livestock may eventually be found in meatproducts consumed by humans. Such contamination canalso occur through the use of certain foodservice chemi-cals such as detergents and sanitizers, or excessive use ofadditives and preservatives.

A physical hazard is the danger posed by the presenceof particles or items that are not supposed to be part of afood product. Chips from broken glasses and metal frag-ments from dishes and tableware fall into the category ofphysical contaminants, as do other foreign objects such aspacking staples, tacks, and pins which can accidentally fallinto food.

125. Which of the following best expresses the point ofthe second paragraph?

A. Despite recent scientific advances, foodborneillness continues to present a serious risk to pub-lic health.

B. Although chemical and physical hazards cancause a foodborne illness, biological hazardspose the most serious risk of food contamina-tion.

C. Knowledge of contamination sources is essen-tial for a foodservice manager to safely operatea food establishment.

D. Biological, chemical, and physical hazards rep-resent the main sources of food contamination.

126. Which one of the following can be inferred from thepassage?

A. The only way for food contamination to resultfrom a physical hazard is for a foreign object toaccidentally fall into food.

B. A restaurant owned by someone who does notpossess accurate information regarding foodcontamination hazards cannot be operatedsafely.

C. Anyone infected by an odorless and tastelesstoxin transmitted by a bacterial growth willdevelop a Staphylococcus food intoxication.

D. It is possible for the root cause of a human illnessto be traced back to a farmer’s use of pesticides.

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127. The author of the passage would most likely agreethat a foodservice manager’s comprehension of thenature of potential food hazards is:

A. crucial to the safety of a foodservice operation.

B. necessarily limited due to the complexity ofcontamination sources.

C. the primary factor in an employer’s decision tohire that manager.

D. utilized exclusively for the prevention of food-borne illness.

128. According to the passage, pathogenic micro-organ-isms (line 20):

A. are the most common form of biological hazard.

B. can only trigger a foodborne illness when alive.

C. are toxins that occur in certain plants and fish.

D. include life forms such as bacteria and parasites.

129. The author of the passage mentions packing staplesand pins in the sixth paragraph most probably inorder to:

A. demonstrate the importance of better methodsof food storage and preservation.

B. prove that certain food hazards are more dan-gerous than others.

C. suggest that it is far easier to prevent physicalhazards than chemical hazards from contami-nating food.

D. provide examples of another type of food con-tamination hazard.

130. Which one of the following actions best accords withthe author’s view of the relationship between recentscientific advances and food safety as that view ispresented in the passage?

A. Motorists drive more recklessly in response tostatistics showing that automobile airbags havemade driving safer.

B. Television producers call for scripts of literaryadaptations due to the successful ratings of atelevision version of a classic Russian novel.

C. Patients with high cholesterol continue to mon-itor their diet despite adding a new cholesterol-lowering drug to their regimen.

D. A veterinarian recommends preventativesurgery for a dog despite the fact that the dog isexhibiting no noticeable signs of illness.

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MCAT FL-4 06/27/2003 11:30 AM

Passage IX (Questions 131-137)

The first condition of desert is that you do somethingor that something be done to you. To deserve punishment,one must have at least acted in the external world and, wecan assume for the time being, this action must have hadan impact on other people. The action must bring about astate of affairs that other people wish either to condemn,reward, or punish. There is no punishment for thoughtsalone—at least in the secular legal systems.

The same principle applies, by and large, to positivedesert. We praise people for what they do, for what theymake of their own lives, and for the contributions theymake to others. We do not reward them simply for havingthe right thoughts.…

We have considerable experience evaluating the nega-tive forms of conduct that lead to criminal punishment.The relevant factors are the value of the interest attackedand the attitude—or state of mind—of theoffender.…Those who kill intentionally are thought to beworse than those who kill recklessly or negligently. Theassumption seems to be that intentional actors invest moreof themselves in the crime and therefore become moreclearly identified with the evil they do. Also, the volun-tariness of the action might be important; if at the time ofthe homicide, the offender suffers from partial insanity—called “diminished responsibility” in the law—the degreeof his culpability is reduced. If the act is less than fully vol-untary, the actor is less than fully responsible for the out-come.

These points are taken for granted in the criminal law,but intriguingly, their analogues do not seem to apply inthe field of positive desert, particularly as measured by themarket. Let’s imagine that the inventor of Velcro thoughthis sticky cloth would make a better mousetrap; micewould get stuck on it, spelling their end. He gets apatent…and puts it on the market. Consumers seize on itand convert it into an all-purpose fastener, sales and royal-ties from which make him a billionaire. Under the princi-ples of capitalism, he deserves the money whether heintended or thought he was doing nothing more than build-ing a better mousetrap.…This, then, represents an asym-metry between the positive and negative desert.

Yet one reason to think that intention matters, even inthe case of positive desert, is the evolution of our thinkingabout attempts. Attempted crimes are signaled by tryingand failing to harm someone, say, by shooting and missing.Though the criminal law initially insisted on actual harm,legal systems around the world began about two centuriesago to punish criminal attempts. The person who tries and

fails deserves punishment simply because he has commit-ted himself to doing evil and has tried to execute his plan.At first blush it seems that we do not reward attempts to dogood that fail, yet pedagogic principles of recent yearsseem to reward effort as well as accomplishment. Thepupil who tries hard deserves recognition whether she suc-ceeds or not. This shift from result to effort represents arecognition that attitude matters for positive desert; there isno positive effort worthy of reward without consciouslyand intentionally setting one’s sights on a goal. Thus itseems that our attitudes toward positive desert may be influx.

It is not surprising that we are relatively more certainabout the conditions for negative than for positive desert.Negative desert has been pondered for centuries in work-ing out the rules that govern the sentencing of convictedcriminals. Positive desert finds no precise institutionalcounterpart. Because there is no area of the law concernedwith measuring appropriate rewards, we are left to rely onour accumulated moral sensibilities about who deservesmore and who deserves less.

131. Which of the following examples of positive desert ismost equivalent to that enjoyed by the inventor ofVelcro?

A. A robber who gives away his stolen merchan-dise to charity is nonetheless punished.

B. A physicist wins the Nobel Prize when the lasershe invented for diffraction studies revolution-izes eye surgery.

C. A patient obtains a needed liver transplant eventhough he brought on his condition by reckless,self-indulgent drinking.

D. A student obtains a high score on an exam eventhough he did not study at all.

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132. What is the nature of the asymmetry between nega-tive and positive desert referred to in line 41?

A. That we punish criminal attempts but generallydo not reward attempts to do good.

B. That legal systems and penal codes are moreprepared to settle issues dealing with negativerather than positive desert.

C. That we diminish punishment if intent was notpresent, but do not diminish rewards similarly.

D. That positive desert takes the form of materialrewards, but negative desert results in loss ofpersonal freedom.

133. Suppose a man sacrificed his own education to earnmoney to finance his brother’s. The brother, how-ever, gambled the money away. With which of thefollowing statements would the author be most likelyto agree?

A. The man’s good intentions are irrelevantbecause right thoughts alone are not worthy ofreward.

B. The man could be held partly responsible for hisbrother’s crime under our legal system.

C. To reward the man for his attempted good deedwould be consistent with punishing attemptedcriminal acts.

D. In fairness, the man should receive the sameamount of positive desert regardless of how thebrother actually used the money.

134. The claim that “there is no positive effort worthy ofreward without consciously and intentionally settingone’s sights on a goal” (lines 56–58) is:

A. necessarily true, given the information pre-sented in the passage.

B. perhaps true, but not supported by evidence inthe passage

C. perhaps true, and supported by evidence in thepassage.

D. necessarily false, given the information pre-sented in the passage.

135. Reducing a criminal’s punishment if he is insane:

A. contradicts the principle of not giving outrewards or punishments on thought alone.

B. exemplifies how desert is determined by generalsocietal judgments rather than well-codifiedrules of law.

C. is justified if the criminal attempt fails and doesnot lead to actual harm to others.

D. demonstrates how intent has been incorporatedinto our determination of negative desert.

136. The author’s primary purpose is to:

A. argue that the legal system should treat negativeand positive desert equally.

B. decry the relative lack of theorization of posi-tive desert.

C. discuss the variant social and institutionalresponses to positive and negative desert.

D. question the ethics of basing systems of punish-ment and reward upon mere intention.

137. What does the author conclude are the minimal con-ditions of negative desert?

I. action

II. impact on others

III. setting one’s sight on a goal

A. I only

B. II only

C. I and III only

D. I, II, and III


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MCAT FL-4 06/27/2003 11:30 AM

MCAT FL-4 06/27/2003 11:30 AM

Writing SampleTime: 60 Minutes

2 Prompts, Separately Timed:30 Minutes Each


MCAT FL-4 06/27/2003 11:30 AM

WRITING SAMPLE

DIRECTIONS: This section is a test of your writing skills. Thesection contains two parts. You will have 30 minutes to completeeach part.

Your responses to the prompts given in the Writing Sample willbe written in the ANSWER DOCUMENT.Your response to Part 1must be written only on the answer sheets marked “1,” and yourresponse to Part 2 must be written only on the answer sheetsmarked “2.” You may work only on Part 1 during the first 30 min-utes of the test and only on Part 2 during the second 30 minutes.If you finish writing on Part 1 before the time is up, you mayreview your work on that part, but do not begin writing on Part 2.If you finish writing on Part 2 before the time is up, you mayreview your work only on Part 2.

Use your time efficiently. Before you begin writing a response,read the assignment carefully and make sure you understandexactly what you are being asked to do. You may use the spacebelow each writing assignment to make notes in planning yourresponses.

Because this is a test of your writing skills, your response to eachpart should be an essay composed of complete sentences andparagraphs, as well organized and clearly written as you canmake it in the allotted time. You may make corrections or addi-tions neatly between the lines of your responses, but do not writein the margins of the answer booklet.

There are six pages in your answer booklet to write yourresponses, three pages for each part of the test. You are notrequired to use all of the pages, but to be sure that you haveenough space for each essay, do not skip lines.

Essays that are illegible cannot be scored. In addition, essaysthat are not written in English will not be scored.

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MCAT FL-4 06/27/2003 11:30 AM

Part 1

Consider the following statement:

Objectivity should be the primary goal in reporting the news.

Write a unified essay in which you perform the following tasks. Explain what you think the abovestatement means. Describe a specific situation in which a news report might justifiably not be completelyobjective. Discuss what you think determines whether or not objectivity should be the primary goal ofnews reporting.

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MCAT FL-4 06/27/2003 11:30 AM

Part 2

Consider the following statement:

The more people rely on computers, the more people become alienated from one another.

Write a unified essay in which you perform the following tasks. Explain what you think the abovestatement means. Describe a specific situation in which computers might not alienate people from oneanother. Discuss what you think determines whether or not computers alienate people from one another.

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MCAT FL-4 06/27/2003 11:30 AM

Biological SciencesTime: 100 MinutesQuestions 138–214


MCAT FL-4 06/27/2003 11:30 AM

54

BIOLOGICAL SCIENCES

DIRECTIONS: Most of the questions in the BiologicalSciences test are organized into groups, with adescriptive passage preceding each group of ques-tions. Study the passage, then select the single bestanswer to each question in the group. Some of thequestions are not based on a descriptive passage; youmust also select the best answer to these questions. Ifyou are unsure of the best answer, eliminate thechoices that you know are incorrect, then select ananswer from the choices that remain. Indicate yourselection by blackening the corresponding circle onyour answer sheet. A periodic table is provided belowfor your use with the questions.

PERIODIC TABLE OF THE ELEMENTS

1

H

1.0

2

He

4.0

3

Li

6.9

4

Be

9.0

5

B

10.8

6

C

12.0

7

N

14.0

8

O

16.0

9

F

19.0

10

Ne

20.2

11

Na

23.0

12

Mg

24.3

13

Al

27.0

14

Si

28.1

15

P

31.0

16

S

32.1

17

Cl

35.5

18

Ar

39.9

19

K

39.1

20

Ca

40.1

21

Sc

45.0

22

Ti

47.9

23

V

50.9

24

Cr

52.0

25

Mn

54.9

26

Fe

55.8

27

Co

58.9

28

Ni

58.7

29

Cu

63.5

30

Zn

65.4

31

Ga

69.7

32

Ge

72.6

33

As

74.9

34

Se

79.0

35

Br

79.9

36

Kr

83.8

37

Rb

85.5

38

Sr

87.6

39

Y

88.9

40

Zr

91.2

41

Nb

92.9

42

Mo

95.9

43

Tc

(98)

44

Ru

101.1

45

Rh

102.9

46

Pd

106.4

47

Ag

107.9

48

Cd

112.4

49

In

114.8

50

Sn

118.7

51

Sb

121.8

52

Te

127.6

53

I

126.9

54

Xe

131.3

55

Cs

132.9

56

Ba

137.3

57

La *

138.9

72

Hf

178.5

73

Ta

180.9

74

W

183.9

75

Re

186.2

76

Os

190.2

77

Ir

192.2

78

Pt

195.1

79

Au

197.0

80

Hg

200.6

81

Tl

204.4

82

Pb

207.2

83

Bi

209.0

84

Po

(209)

85

At

(210)

86

Rn

(222)

87

Fr

(223)

88

Ra

226.0

89

Ac †

227.0

104

Rf

(261)

105

Ha

(262)

106

Unh

(263)

107

Uns

(262)

108

Uno

(265)

109

Une

(267)

*

58

Ce

140.1

59

Pr

140.9

60

Nd

144.2

61

Pm

(145)

62

Sm

150.4

63

Eu

152.0

64

Gd

157.3

65

Tb

158.9

66

Dy

162.5

67

Ho

164.9

68

Er

167.3

69

Tm

168.9

70

Yb

173.0

71

Lu

175.0

†

90

Th

232.0

91

Pa

(231)

92

U

238.0

93

Np

(237)

94

Pu

(244)

95

Am

(243)

96

Cm

(247)

97

Bk

(247)

98

Cf

(251)

99

Es

(252)

100

Fm

(257)

101

Md

(258)

102

No

(259)

103

Lr

(260)

MCAT FL-4 06/27/2003 11:30 AM


Carbon exists in a number of natural solid forms orallotropes. Graphite and diamond (shown in Figure 1) arethe most familiar. Graphite is composed of planar sheets oflinked carbons while each carbon in diamond is bondedtetrahedrally to four neighboring carbons.

Figure 1

A different form of naturally occurring carbon, buck-minsterfullerene, was discovered in 1985. Researchersattempting to synthesize large carbon chains were sur-prised by the results of mass spectrometry on the samplesproduced. A single peak at 720 amu predominated. Underthe experimental conditions, the formation of this 60 car-bon molecule was particularly favorable. The researcherssuspected, and it was later confirmed by NMR, that thestructure of this 60 carbon molecule was the soccer ball-like buckminsterfullerene, or Buckyball. Figure 2 showsthe front of a Buckyball (the carbons in back are notshown).

Figure 2

The Buckyball has both 6 and 5-membered ringsjoined together to form a spherical structure. Each carbonis bonded to three neighbors, giving a pattern of alternat-ing single and double bonds as the carbon-carbon bondstructure is traced. Different resonance structures can bedrawn for the Buckyball and resonance stabilization con-tributes to the very high stability of this form of carbon.The Buckyball (C60) reacts in a manner similar to electron-deficient alkenes such as tetracyanoethylene.

138. Identify the 1H NMR spectrum of C60 (Buckminster-fullerene):

A.

B.

C.

D.

139. What are the hybridization(s) of the carbon atoms inC60 (Buckyball)?

A. sp2

B. sp3

C. sp and sp2

D. sp2 and sp3

4.0 3.0 2.0 1.0 05.06.0PPM ( δ )

4.0 3.0 2.0 1.0 05.06.0PPM ( δ )

4.0 3.0 2.0 1.0 05.06.0PPM ( δ )

4.0 3.0 2.0 1.0 05.06.0PPM ( δ )

Graphite Diamond

55

GO ON TO THE NEXT PAGE.GO ON TO THE NEXT PAGE.

MCAT FL-4 06/27/2003 11:30 AM

140. Which of the three naturally occurring states of car-bon has the greatest angle strain?

A. graphite

B. buckminsterfullerene

C. diamond

D. Angle strain is the same in all three.

141. A researcher wishes to dissolve a sample of C60 foranalysis. Which of the following solvents would bemost appropriate?

A. benzene

B. acetone

C. ethanol

D. DMSO (dimethyl sulfoxide)

142. How many moles of hydrogen gas (H2) would beused in the hydrogenation of a mole of C60 on a plat-inum catalyst?

A. 30

B. 40

C. 60

D. 120

143. Which of the following organic compounds wouldreact in a manner most similar to buckminster-fullerene (C60)?

A. B.

C. D.

144. What compound reacted with C60 to form the follow-ing Diels-Alder adduct?

A.

B.

C.

D.

S

S

OCH3

O

O

OCH3

S

OCH3

OCH3

S

OCH3

S

O

O

O

H3C CH3

OCH3

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MCAT FL-4 06/27/2003 11:30 AM


In the average adult, the small intestine absorbs around7 liters of water per day. Most of the water is transportedpassively, driven by the osmotic gradient generated bysodium-potassium pumps in the capillary-side membraneof the epithelial cells. It has been suggested that water isalso brought into the cell by secondary active transport,coupled to the transport of sodium and glucose into theepithelial cells by proteins in the lumenal membrane.

The osmotic movement of water has been understoodfor many years. Sodium pumps in the membrane adjacentto the capillaries transport sodium out of the cell into theinterstitial fluid. This lowers the concentration of sodiumwithin the cell and generates a high concentration ofsodium in the interstitial fluid. Sodium is absorbed fromthe lumen of the small intestine, down its concentrationgradient, in co-transport with glucose or amino acids. Inconcert with the movement of sodium from the lumen intothe interstitial space, water moves by osmosis, through thecell and across the tight junctions between cells. Bothwater and sodium then diffuse into the capillary system ofthe villus. It is important to note that water can diffuseacross the phospholipid bilayer directly. Although thismovement of water is associated with the transport ofsodium (and other solutes), it is not directly coupled withthe activity of a membrane transport protein.

Passive osmosis can only occur from a hypotonic to ahypertonic environment. Thus, it does not describe theability of the small intestine to absorb water when the con-tents of the small intestine have a higher osmolarity thanthe blood. It has been proposed that Na+-glucose-watercotransport proteins exist. These membrance proteinsmove a water molecule into the cell with each sodium ionand glucose molecule it caries across the membrane. Theseproteins can transport water uphill (against the water con-centration gradient) and provide an explanation for theobserved absorption of water when the lumenal contentsare hyperosmolar.

145. Assume that water is only transported by passivemechanisms. Which of the following best describesthe effect of oubain, a Na+/K+ ATPase inhibitor, onthe absorption of water in the small intestine?

A. Water will only be absorbed if the lumen ishypertonic to the blood.

B. Water will only be absorbed if the lumen ishypotonic to the blood.

C. Water will be absorbed if the lumen is hyper-tonic or isotonic to the blood.

D. Water will be absorbed if the lumen is hypotonicor isotonic to the blood.

146. A researcher observes no absorption of water from ahypertonic Na+ solution in the lumen of a small intes-tine tissue sample. Which of the following observa-tions would support the claim that water is absorbedby secondary active transport, as described in thepassage?

A. Addition of Na+ to the lumen does not promotewater absorption.

B. Dilution of the lumen solution promotes waterabsorption.

C. Addition of glucose to the lumen promoteswater absorption.

D. Addition of Na+ to the lumen promotes waterabsorption.

147. A single intestinal epithelial cell is exposed to an iso-tonic solution of salts, glucose and amino acids.Which of the following would be a good means ofmonitoring the relative activity of the proposed waterco-transporter?

A. Tracking the usage of ATP with radio-labelledphosphate.

B. Measuring minute changes in cell volume overtime.

C. Observing the uptake of radio-labelled glucose.

D. Measuring cell metabolic activity throughpurification of mitochondrial by-products.

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148. Endothelial cells lining the digestive tract are said tobe polarized because they:

A. are electrically charged.

B. absorb light with a particular electric field ori-entation.

C. have regions of the membrane that differ in theirconstituents.

D. absorb water in an active mechanism.

149. All of the following utilize a membrane carrier pro-tein EXCEPT:

A. lysine

B. water

C. cholesterol

D. glucose

150. The large intestine uses the same passive absorptionmechanism described in the passage to absorb thewater which the small intestine was insufficientlyefficient to absorb. Which of the following character-istics of the large intestine contributes to the greaterefficiency of this mechanism in the large intestinethan in the small intestine?

A. The endothelium of the large intestine hastighter tight junctions that block the leakage ofsodium ion back into the lumen.

B. The large intestine endothelium has more pow-erful Na+/K+ pumps that transport 5 Na+ foreach ATP hydrolyzed.

C. The greater surface area of the large intestineendothelium facilitates more efficient absorp-tion.

D. The greater length of the large intestine providesa longer exposure to the lumenal contents.

151. Which diagram best illustrates the co-transporterproposed in the last paragraph of the passage?

A.

B.

C.

D.

lumen

cytoplasm

Na+

glucoseH2O

lumen

cytoplasmglucose

Na+H2O

lumen

cytoplasm

2K+

glucose3Na+

lumen

cytoplasm

3Na+

2K+

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MCAT FL-4 06/27/2003 11:30 AM

Passage III (Questions 152–157)

Human cells use metabolites of arachidonic acid aschemical mediators to elicit a wide variety of responsessuch as vasodilation, clot formation and bronchoconstric-tion. The pathway of arachidonic acid (AA) metabolismbegins with the rate-determining step, the conversion ofphospholipids to arachidonic acid. The pathway proceedsas follows:

It is medically useful to inhibit the formation of AAmetabolites. Aspirin (acetylsalicylic acid) inhibitscyclooxygenase, thereby serving to reduce pain and fever.Aspirin is rapidly converted to the metabolically activeproduct salicylic acid via an acid catalyzed deacylationreaction:

Reaction 1

152. What is the IUPAC name for salicylic acid?

A. o-hydroxybenzoic acid

B. 1-hydroxybenzoic acid

C. 2-carboxyphenol

D. 1-hydoxy-2-carboxybenzene

153. What is the relationship between prostaglandins D2

and E2?

A. Structural isomers

B. Enantiomers

C. Diastereomers

D. Geometric isomers

154. What is the other reactant used in the acid catalyzeddeacylation of aspirin shown in Reaction 1?

A. Acetone

B. Water

C. Lithium aluminum hydride (LiAlH4)

D. Ethanol

155. Which of the following CANNOT be the rate law forthe production of AA metabolites?

A. R = k[arachidonic acid][cyclooxygenase]

B. R = k[phospholipase A2]

C. R = k[phospholipase A2][phospholipid]

D. R = k[phospholipase A2][phospholipid]2

156. The molecule PGH2 can be classified as which of thefollowing?

A. Alkyne

B. Ether

C. Ketone

D. Peroxide

157. Which of the following descriptions is NOT consis-tent with the deacylation of aspirin?

A. Nucleophilic acyl substitution

B. Ester hydrolysis

C. Electrophilic addition

D. Equilibrium controlled

OH

O

O

O

H3C

OH

O

OH

Salicylic acid

H+

H3C OH

O

+

Aspirin

COOH

O

O

COOH

OOH

O

O

COOH

OH

COOH

OHO

O

COOH

OHOH

O

COOH

OHO

OH

Phoshoplipase A2

Prostaglandin D2 (PGD2)

Arachidonic Acid (AA)

Thromboxane A2 (TXA2)Cyclooxygenase Aspirin

Prostaglandin E2 (PGE2)

Cell Membrane Phospholipids

Prostaglandin H2 (PGH2)

Prostaglandin G2 (PGG2)

59


MCAT FL-4 06/27/2003 11:30 AM

Questions 158 through 162 are NOT basedon a descriptive passage.

158. Which of the following is the correct sequence ofevents during inspiration of heavy breathing?

A. Diaphragm contracts → rib cage expands →intrathoracic pressure drops → air enters lungs

B. Intrathoracic pressure drops → diaphragm con-tracts → rib cage expands → air enters lungs

C. Diaphragm contracts → intrathoracic pressuredrops → rib cage expands → air enters lungs

D. Rib cage expands → diaphragm contracts →intrathoracic pressure rises → air enters lungs

159. What is the approximate pH of the intermembranespace of a mitochondrion?

A. 6

B. 7

C. 8

D. 10

160. Which of the following compounds is aromatic?

A. C.

B. D

161. β-D-(+)-Glucopyranose has a specific rotation of+18.7°. In solution, however, an equilibrium is grad-ually established with the α-anomer. What happensto the specific rotation of a sample of the β-anomerin solution as time goes on?

A. remains at +18.7°

B. decreases until it reaches 0°

C. decreases until it reaches –18.7°

D. cannot be predicted without more information

162. Which of the following is a β-hydroxy ketone?

A. C.

B. D.

H

O OHO

OH

O

OH

O

OH

60


MCAT FL-4 06/27/2003 11:30 AM

Passage IV (Questions 163–168)

Leber’s hereditary optic neuropathy (LHON) is a neu-rodegenerative disease of the optic nerve that causes bilat-eral loss of central vision that eventually leads toblindness.

LHON is an unusual genetic disease in that it resultsfrom a mutation in the mitochondrial genome. The defectis a transition mutation where an adenine is erroneouslysubstituted for a guanine.

A definitive diagnosis of LHON is made through anal-ysis of a person’s DNA. A sample of a patients DNA isamplified via PCR technology and then analyzed for thegain or loss of restriction enzyme sites. Restrictionenzymes are bacterial DNAases that recognize specificDNA sequences (about 6 nucleotides in length) and cleavethe DNA at that site. The digested DNA is then run throughgel electrophoresis to separate the DNA fragments accord-ing to size. Larger fragments cannot pass through the gelas freely as smaller fragments and so remain closer to thetop of the gel.

A researcher analyzing a patient’s DNA performs arestriction enzyme analysis using the restriction enzymeAcc I. The LHON mutation causes the loss of the Acc Irestriction enzyme site. Lane 1 contains DNA size mark-ers, lane 2 contains an undigested sample of the patient’sDNA, lane 3 contains a normal DNA sample treated withAcc I, and lane 4 contains the patient’s sample treated withthe enzyme.

Figure 1

A sample that is suspected of having the LHON defectis confirmed by DNA sequencing. As evidenced from Fig-ure 2, there is a loss of guanine and an addition of adenineat the expected location within the gene controlling thedisease.

Figure 2

163. A transition mutation is:

A. a point mutation in which a purine is substi-tuted for a purine.

B. a point mutation in which a pyrimidine is sub-stituted for a purine.

C. an insertion mutation in which a purine is sub-stituted for a purine.

D. an insertion mutation in which a pyrimidine issubstituted for a purine.

164. The patient whose DNA digest is shown in Figure 1:

A. gained an Acc I site and has LHON.

B. gained an Acc I site and does not have LHON.

C. lost an Acc I site and has LHON.

D. lost an Acc I site and does not have LHON.

165. A researcher analyzing a sample of DNA performs arestriction enzyme analysis using the restrictionenzyme Mae III. The LHON mutation causes a gainof a Mae III restriction enzyme site. Compared tonormal DNA treated with this enzyme, the DNAfrom a patient with LHON treated with Mae IIIwould be expected to:

A. travel a shorter distance during gel elec-trophoresis.

B. travel a greater distance during gel elec-trophoresis.

C. travel the same distance during gel elec-trophoresis.

D. travel the same distance as it would if it werenot treated with the Mae III enzyme.

NormalMitochondrial Genome

MutantMitochondrial Genome

G A T C G A T C

1 2 3 4Sample Start

Dir

ectio

n of

mig

ratio

n

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MCAT FL-4 06/27/2003 11:30 AM

166. The LHON mutation results in a defective cytochromeprotein of similar molecular weight to the normal pro-tein. The mutation is best described as:

A. Frame shift

B. Non-sense

C. Missense

D. Silent

167. Although LHON invariably leads to blindness, thepatients pupillary responses to light remain intact.This suggests that:

A. drops of epinephrine applied to the eye willcause pupil dilation.

B. the afferent nerve fibers are completelydestroyed.

C. the sympathetic response of pupil contraction isintact.

D. the patient can regain their vision.

168. Sperm that are to be used for artificial inseminationare not checked for the genetically inheritable LHONbecause:

A. restriction enzyme analysis is expensive andtime consuming.

B. sperm with defective mitochondria do not pro-duce enough energy to reach the egg.

C. the acrosomal reaction cannot occur with spermthat have defective mitochondria.

D. when sperm and egg fuse, mitochondria do notenter the egg.

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MCAT FL-4 06/27/2003 11:30 AM

Passage V (Questions 169–174)

Neurons have a long process called the axon that prop-agates action potentials away from the cell body towards adistant target cell. In humans, the longest axons can extendup to a meter from the base of the spinal cord to the tip ofthe big toe. The axon ends at a synapse— the point atwhich the electrical signal is converted to a chemical sig-nal and passed on to an effector (such as a gland or mus-cle) or to another nerve cell. The distance of the axonterminal from the locus of the neuron’s metabolic activitynecessitates an efficient transport mechanism for movingmaterials along the axon.

Microtubules extend across the length of the axon.Microtubules have a polar structure, and in the axon all ofthe microtubules are directed with their positive endstowards the synapse. In contrast, the microtubules in den-drites can be oriented in both directions.

Specialized motor proteins carry materials towards thesynapse (anterograde transport) or towards the cell body(retrograde transport). Kinesins are responsible for theanterograde transport of membrane-bound organelles. Theorganelles bind to kinesins which are themselves bound tothe microtubules. With each ATP hydrolyzed, the kinesin“walks” down the microtubule, taking 9 nm “steps” as ittransports the vesicle to the axon terminal at a rate of about1 µm per second.

Dyneins are primarily responsible for retrograde trans-port. Materials taken up at the axon terminal are trans-ported back towards the cell body for processing. Althoughthe mechanism of transport differs from that of kinesins,both utilize the microtubule cytoskeleton.

169. A researcher studying the movement of materialsthrough a squid axon ties a thin string around theaxon to cut off the flow of materials. After a fewhours, the researcher examines the materials oneither side of the ligature. According to the passage,the researcher should find:

A. more motor proteins on the cell body side of thestring.

B. more motor proteins on the synapse side of thestring.

C. more dyneins on the cell body side of the string.

D. more kinesins on the cell body side of the string.

170. Some neurotransmitters have inhibitory effects onthe post-synaptic neuron, making it more difficult tostimulate the cell to fire an action potential. Theseinhibitory neurotransmitters function by:

A. binding antagonistically to receptors for stimu-latory neurotransmitters.

B. blocking the re-uptake of stimulatory neuro-transmitters by pre-synaptic cell.

C. hyperpolarizing the post-synaptic cell mem-brane by opening ion channels.

D. setting voltage-gated sodium channels to the“off” conformation characteristic of the actionpotential refractory period.

171. Kinesins transport all of the following EXCEPT:

A. excitatory neurotransmitter receptors.

B. neurotransmitter proteins.

C. phospholipids.

D. voltage-gated ion channel proteins.

171. Action potentials originating at the axon hillock of thecell body are carried towards the axon terminal by:

A. kinesins.

B. dyneins.

C. local transmembrane ion fluxes.

D. anterograde movement of sodium ions.

173. The membrane components of neurotransmitter vesi-cles are labelled with radioactive phosphorus andallowed to travel along a nerve axon. Followingsecretion of their neurotransmitter, the radiolabelledphosphorus will be found in:

A. the axon terminal membrane

B. vesicles bound to kinesins in the axon

C. the synaptic cleft

D. the post-synaptic cell membrane

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MCAT FL-4 06/27/2003 11:30 AM

174. The by-products of neurotransmitters released intothe synapse are taken up by the axon terminal forprocessing in the cell body. A researcher wishes topurify these by-products from a neuron cytoplasmextract. Microtubules are aligned on a glass surfacewith their plus-ends towards the right. The extract isplaced on the middle of the surface. In order to col-lect the desired components, the researcher shouldcollect components that:

A. remained in the center of the glass surface.

B. were enclosed in membrane bound vesicles.

C. flowed to the right side of the glass surface.

D. flowed to the left side of the glass surface.

64


MCAT FL-4 06/27/2003 11:30 AM

Passage VI (Questions 175–181)

The following elimination reaction was carried out,and its kinetics were monitored.

Reaction 1

The rate of the reaction is found to be proportional toboth the concentration of the haloalkane and the concen-tration of the ethoxide ion. Two mechanisms, both consis-tent with the observed second order kinetics, wereproposed.

Mechanism A:

The reaction is bimolecular and has only one step, inwhich the proton extraction by the ethoxide and the depar-ture of the chloride are concerted and take place in anantiperiplanar configuration. This is known as E2.

Mechanism B:

The reaction progresses through two steps. The firststep consists of the extraction of a proton by the ethoxideion from the haloalkane, leading to the formation of ananion intermediate, CH3CH–CHClC(CH3)3. This interme-diate may either go back to reform the reactant(haloalkane), or may undergo a second, rate-determiningstep in which the chloride ion leaves and the carbon-car-bon double bond forms. This mechanism is given the nameE1cB, where the “1” refers to the fact that the rate-deter-mining step involves the reaction of only one molecule(the anion), and “cB” stands for conjugate base, again inreference to the anionic intermediate. Even though therate-determining step is unimolecular, the concentration ofthe intermediate is dependent on both the base concentra-tion and the substrate concentration, and so the reactionexhibits second order kinetics overall.

An E1cB-like mechanism is thought to be operative incertain aromatic substitution reactions. Most aromatic sub-stitution reactions are electrophilic and proceed through anaddition-elimination pathway. Nucleophilic aromatic sub-stitutions, however, proceed through an elimination-addi-tion pathway, in which a substituted benzene undergoes anE1cB-like reaction. The product of this reaction then under-goes addition to yield the desired substitution product.

175. Which of the following is the correct reaction profilefor the E1cB mechanism as described in the passage?

176. Which of the following, if true, would most supportthe E1cB mechanism over the E2 mechanism in theelimination reaction described?

A. Use of a heavier isotope of chlorine in the start-ing molecule slows down the reaction.

B. Use of a bulky base favors elimination over sub-stitution.

C. Use of deuterated solvent results in deuteriumbeing incorporated into the reisolated startingproduct.

D. Doubling the concentration of the base leads toa doubling of the reaction rate.

177. Which of the following molecules would react toform the most stable intermediate under the E1cBmechanism?

H

CH3C

H

C

CH3

CH3

F

A.

H

CH3C

H

C

CH3

F

F

B.

H

CCl

H

C

CH3

F

F

C.

H

CCl

Cl

C

F

F

F

D.

A.

reaction coordinate

ener

gy

C.

reaction coordinate

ener

gy

B.

reaction coordinate

ener

gy

D.

reaction coordinate

ener

gy

CH3CH2CHC(CH3)3

Cl

+ CH3CH2O– CH3CH=CHC(CH3)3

+ CH3CH2OH + Cl–

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MCAT FL-4 06/27/2003 11:30 AM

178. What are the two intermediates, X and Y respec-tively, in the nucleophilic aromatic substitution reac-tion of bromobenzene to form aniline(aminobenzene) shown below?

179. If, in the E1cB mechanism, the formation of theanion intermediate were rate-determining, which ofthe following can be concluded?

A. It would lead to first order kinetics.

B. The nature of the leaving group would have nosignificant effect on the kinetics.

C. The intermediate would be thermodynamicallymore stable than when the second step is rate-determining.

D. The intermediate would be thermodynamicallymore stable than the starting haloalkane.

180. What would be the E2 elimination product of the fol-lowing molecule?

CH2CH3H3C

CH2CH3H3C

A.

CH2CH3H3C

CH3H3CH2C

HH

CH2CH3H3CH2C

HH

CH(CH3)2H3CH2C

B.

C.

D.

Br

CH3H3CH2C

CH2CH3H3C

H

Br

Br

Br

A.

B.

C.

D.

Br

+ NH2–

X Y

NH2

NH2

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MCAT FL-4 06/27/2003 11:30 AM

181. In principle, both the cis and the trans isomer can beformed in Reaction 1. Which of the following state-ments is true?

A. The cis isomer is thermodynamically more sta-ble because alkyl groups are electron-donatingrelative to hydrogen atoms.

B. The cis isomer is thermodynamically more sta-ble because it is more polar and has a higherboiling point.

C. The trans isomer is thermodynamically morestable because there is less steric crowding.

D. The trans isomer is thermodynamically morestable because it is less polar and thus has lesscharge separation.

67


MCAT FL-4 06/27/2003 11:30 AM

68


Passage VII (Questions 182–187)

Humans have a remarkable ability to acclimatize tohigh altitudes up to 12,000 ft. with little detrimental effect.

Figure 1

When a mountain climber ascends to 10,000 ft, theatmospheric pO2 can decrease from 104 mmHg (at sealevel) to 60 mmHg. Figure 1 shows that at 60mmHg, thehemoglobin is still around 90% saturated. At this altitude,when the hemoglobin releases oxygen to the tissues, thevenous blood pO2 falls to 35 mmHg, only 5 mmHg lowerthan its normal value. Hemoglobin’s bonding characteris-tics are very effective at maintaining delivery of oxygen,but the body can actually alter its functioning in a numberof ways to respond to low atmospheric pO2.

Acclimatization to altitude occurs in a number ofways:

I. The body immediately responds by increasingventilation to around 65% above normal. Thisincrease leads to the exhalation of CO2 and anincrease in blood pH which tends to inhibit therespiratory center and oppose the stimulatoryeffect of decreased pO2. Over a period of 2-5days, this inhibition declines and ventilation canincrease up to five times normal.

II. After about 2 weeks at high altitude, the concen-tration of erythrocytes increases. Consequently,hemoglobin concentration in the blood increasesas well.

III. At the time of exposure to low atmospheric pres-sure, the body increases cardiac output. The car-diac output falls back to normal after about 2weeks. Over time, there is an increase in the cap-illarity of the tissues.

IV. In humans native to high altitudes, mitochondriaand oxidative enzymes are more plentiful than inhumans born at sea level. This cellular acclimati-zation allows more efficient oxygen utilization.

182. According to the graph in Figure 1, under normalconditions, the bodies tissues utilize approximately:

A. 75% of the oxygen bound to Hb.

B. 75% of the oxygen transported in the blood (insolution and bound to Hb).

C. 50% of the oxygen transported in the blood (insolution and bound to Hb).

D. 25% of the oxygen bound to Hb.

183. Within the normal range of blood pO2, mosthemoglobin molecules bind how many oxygenmolecules?

A. 1 to 2

B. 1 to 4

C. 2 or 3

D. 3 or 4

184. A blood sample taken 1 week following exposure tohigh altitude would contain:

A. a significantly higher concentration of erythro-cytes.

B. a somewhat higher concentration of erythropoi-etin.

C. a much lower concentration of erythropoietin.

D. a significantly lower volume of oxygen (in solu-tion and bound to hemoglobin)

20

18

16

14

12

10

8

6

4

2

00 20 40 60

Oxy

gen

in b

lood

(V

ol %

)

80 100 120pO2 in blood (mmHg)

bHotdnuobnegyxO

veno

us b

lood

(se

a le

vel)

arte

rial

blo

od (

sea

leve

l)

100

90

80

70

60

50

40

30

20

10

0H

b Sa

tura

tion

(%)

MCAT FL-4 06/27/2003 11:30 AM

185. According to the passage, 2 weeks after exposure tohigh altitude, the cardiac output falls back to its nor-mal level. This does not impair the delivery of oxy-gen to the tissues because:

A. although the heart rate decreases, the stroke vol-ume remains the same.

B. the respiratory rate will have increased to 65%of its normal value.

C. after two weeks, the concentration ofhemoglobin in the blood has increased and thusoxygen transport is more efficient.

D. after two weeks, the number of mitochondria inthe cells has increased and thus oxygen trans-port is more efficient.

186. The acclimatizations described in the passage wouldalter the curve in Figure 1:

A. by shifting it to the right.

B. by shifting it to the left.

C. by increasing the slope.

D. not at all.

187. At an altitude of 10,000 feet, blood in the pulmonaryarteries has a pO2 closest to:

A. 90 mmHg

B. 60 mmHg

C. 40 mmHg

D. 35 mmHg

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MCAT FL-4 06/27/2003 11:30 AM


188. Which of the following would be expected to con-tain an abundant amount of smooth endoplasmicrecticulum?

A. adrenal cortical cells

B. epithelial cells

C. endothelial cells

D. adipose cells

189. Which of the following intramolecular forces helpstabilize the DNA double helix?

I. Hydrogen bonding between complemen-tary nitrogenous bases.

II. Electostatic attraction between adjacentphosphate groups.

III. Hydrogen bonding between adjacent ribosesugars.

A. I only

B. I and II only

C. I and III only

D. I, II and III

190. A scientist transplants embryonic cells from the armbud of a fetal frog to the head. The cells continue todevelop into an arm. The removed cells must havebeen:

A. Totipotent

B. Differentiated

C. Mutant

D. Determined

191. Which of the following bonds is broken when ATP ishydrolyzed to ADP?

A. A

B. B

C. C

D. D

192. The widespread use of anti-bacterial soaps has leadto a greater prevalence of resistant strains of bacteria.This is an example of:

A. stabilizing selection.

B. directional selection.

C. disruptive selection.

D. speciation.

193. Osteoblasts secrete large quantities of alkaline phos-phatase when they are actively depositing bonematrix. Insufficient dietary calcium would be indi-cated by:

A. increased concentration of alkaline phosphatasein the circulation.

B. decreased concentration of alkaline phosphatasein the circulation.

C. decreased concentration of osteoclasts in thecirculation.

D. increased concentration of Ca++ in the circulation.

HC

NC

CN

C

C

O

C

C

NCH

NC

H2N

H2C O P

O-

O

O

HH

OH

H

OH

H

P

O

O-

O P

O

O-

O-A

B C D

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MCAT FL-4 06/27/2003 11:30 AM

Passage VIII (Questions 194–197)

A student carried out the extraction of caffeine from tealeaves as follows: Four tea bags were boiled in 100 mL ofdistilled water with sodium carbonate for 10 minutes.Impurities known as tannins precipitated out in the form ofsodium salts. After removing the tea bags and filtering outthe precipitate, the aqueous solution was cooled to roomtemperature with an ice bath.

An extraction was then performed in a separatory fun-nel with three washings of dichloromethane (CH2Cl2), eachof 20 mL. The CH2Cl2 extractions were washed withNaOH, a procedure that helps to remove more tannins. Thesolvent was then evaporated off on a hot plate. The lightgreen residue left behind had a melting point of198–201°C, compared to the literature value of 238°C forthe melting point of caffeine. This residue was then subli-mated under vacuum to yield a white crystalline substancecorresponding to the pure product.

The structure of caffeine is shown below in Figure 1.

Figure 1

194. Which of the following can be concluded abouttannins?

A. They can act as a Lewis base.

B. They possess acidic protons.

C. They are of low molecular weight.

D. They are insoluble in CH2Cl2.

195. If thin layer chromatography is performed on thelight green residue using CH2Cl2 as the solvent,which of the following would be true?

A. There would be one spot with a high Rf value.

B. There would be one spot with a low Rf value.

C. The spot would disappear as the caffeine dis-solves in the solvent.

D. Several spots with different Rf values would beobserved.

196. If a strong acid were added to the aqueous solutionbefore the CH2Cl2 extraction:

A. the extraction would fail because the caffeinewould remain in the aqueous phase.

B. the extraction would fail because the CH2Cl2

would become protonated.

C. the extraction would work but more NaOH isneeded in the subsequent washings.

D. the extraction would work but no NaOH shouldbe used in the subsequent washings.

197. What is the bond angle θ indicated below?

A. 90°

B. 107°

C. 109.5°

D. 120°

N

N N

N

O

O

H3C

CH3

CH3

θ

N

N N

N

O

O

H3C

CH3

CH3

71


MCAT FL-4 06/27/2003 11:30 AM

Passage IX (Questions 198–203)

Diseases that affect renal function can grouped accord-ing to two syndromes, the nephrotic and nephritic.

Nephrotic Syndrome

The nephrotic syndrome is caused by the release of anunknown chemical mediator from leukocytes, possiblyfrom T-cells, that damages glomerular capillary beds. Pro-teoglycans that electrostatically repel proteins from Bow-man’s capsule are damaged, allowing proteins (mostlyalbumin, the predominant protein in the blood) to leak intothe nephron. Reabsorptive mechanisms are quickly over-whelmed, resulting in a sustained proteinuria that causes asevere drop in serum albumin levels resulting in decreasedplasma osmotic pressure. This drop in osmotic pressurecauses generalized swelling of the body, especially theextremities.

Nephritic Syndrome

The nephritic syndrome is the result of an uncheckedinflammatory response. Circulating immune complexesdeposit beneath the capillary epithelial cells of theglomeruli, attracting leukocytes that infiltrate and injurethe cells by stimulating an inflammation reaction. Thedamage allows red blood cells to enter the nephron, butdoes not allow a significant amount of protein to escape.The blood loss induces hemodynamic changes that reducethe amount of blood reaching the kidneys, causingdecreased urine production. The retention of water andrelease of renin result in severe hypertension.

To determine if a person has an abnormal amount ofprotein in their urine, a total protein assay is performed. A24-hr urine sample is collected and the amount of light thesample absorbs is measured using a spectrophotometer.The protein concentration can then be determined using acalibrated curve, like the one shown in Figure 1. The nor-mal range for total protein urine concentration is 3.5 – 5.0gm/dL.

Figure 1

198. Which of the following is true for both the nephroticand nephritic syndromes?

A. Elevated protein in the urine

B. Blood in the urine

C. Hypertension

D. Immune mediated

199. What is the most likely mechanism for protein reab-sorption in the proximal convoluted tubule?

A. Diffusion

B. Facilitated diffusion

C. Primary active transport

D. Endocytosis

200. Why is swelling part of the nephrotic syndrome?

A. Injury to the nephron causes water retention.

B. Fluid cannot be reabsorbed at the venule end ofcapillaries.

C. The drop in osmotic pressure results in ADHrelease, resulting in water reasbsorption andswelling.

D. The drop in blood pressure stimulates the Star-ling response, which serves to increase interstitialfluid.

5.0

4.0

3.0

2.0

1.0

0 20 40 60 80 100

Total Protein (mg/mL)

Abs

orpt

ion

Patient A B C D

Absorption 1.0 1.9 3.25 1.75

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MCAT FL-4 06/27/2003 11:31 AM

201. How can the release of renin cause hypertension?

A. It stimulates an increases in salt and water reab-sorption.

B. It stimulates the release of ADH, resulting inwater reabsorption.

C. It stimulates the release of cortisone from theadrenal glands, resulting in salt and water reab-sorption.

D. It activates the sympathetic nervous system,causing vasoconstriction.

202. In a normal individual, all of the following are fil-tered through the glomerulus into Bowman’s capsuleEXCEPT:

I. Sodium

II. Urea

III. Red blood cells

A. I only

B. II only

C. III only

D. II and III only

203. Which of the following patients have proteinuria?

A. A

B. A and B

C. C

D. B and D

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MCAT FL-4 06/27/2003 11:31 AM

74


Passage X (Questions 204–210)

The Baeyer-Villiger oxidation is a method of convert-ing ketones to esters. A peracid (RCO2OH), which containsa peroxide bond, attacks the carbonyl carbon of a proto-nated ketone to give a tetrahedral intermediate known

as the Criegee intermediate. The intermediate then pro-ceeds to form the ester via the migration of an alkyl groupas the carboxylic acid is displaced. A partial mechanism isshown below:

R1

O

R2 R1

OH

R2 R1

OH

R2

R3

O

O OH

R1

OH

R2

OO

OR3

R1

OH

R2

OO

OHR3

OH

O R2

R1

O

OHR3

O

O R2

R1

H+ –H+

–H+

+

H+

(rate-determining step)

O OO

HOOCH3

O

CH3CO3H

CHCl3, H+

OCH3

O

O

X

Y

Either one of the two alkyl groups in the startingketone can in principle migrate, leading to the formation oftwo different esters (assuming R1 ≠ R2). The tendency of agroup to migrate is known as its migratory aptitude, and

generally increases in parallel with the ability to stabilizepositivecharge. Migratory aptitude therefore decreases inthe following order: tertiary alkyl > secondary alkyl > pri-mary alkyl > methyl.

Figure 1

A student carries out the following reaction:

Figure 2

MCAT FL-4 06/27/2003 11:31 AM

204. The major product of the Baeyer-Villiger oxida-tion of 2-butanone is:

A. Ethyl acetate

B. Methyl acetate

C. Ethyl propanoate

D. Methyl propanoate

205. Which of the following R groups is expected tohave the highest migratory aptitude in a methylketone, CH3COR?

206. The second step in the reaction shown in Figure 2 isa transesterification and the third step is an oxidation.The unknown reagents X and Y are:

A. NaOH and KMnO4 respectively

B. NaOH and PCC respectively

C. CH3CH2OH and KMnO4 respectively

D. CH3OH and PCC respectively

207. In the reaction shown in Figure 2, if the startingketone were O-18 labeled, where would the isotopiclabeling end up in the product?

A. (i)

B. (ii)

C. (iii)

D. Incorporated into a solvent molecule

208. How many chiral centers does the starting compoundin the reaction shown in Figure 2 have?

A. 1

B. 2

C. 3

D. 4

209. In the transition state of the rate-determining step ofthe Baeyer-Villiger oxidation (Figure 1), a partialbond exists between all of the following pairs ofatoms EXCEPT:

A. The carbonyl carbon of the starting ketoneand the carbon atom of the migrating group

B. The attacking oxygen on the peracid and thecarbon atom of the migrating group

C. The carbonyl carbon of the starting ketoneand the attacking oxygen on the peracid

D. The two oxygen atoms of the peracid

210. Which of the following is the strongest acid?

A. CH3CO3H

B. CF3CO3H

C. C6H5CO3H

D. C6H5CH2CO3H

OCH3

O

O(i)

(ii)

(iii)

A.

B.

C.

D.

CH3

OCH3

Cl

CF3

R = R =

R =R =

75


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211. The 1H NMR of which of the following moleculeshas the most shielded proton absorption spectrum?

A. CH3Br

B. CH3F

C. CH2CH2

D. CH4

212. The five-membered imino ring of the amino acidproline prevents the α-amine nitrogen from partici-pating in hydrogen bonding. Which of the followingis true?

A. Proline cannot form peptide bonds.

B. Proline cannot be part of a β-pleated sheet.

C. Proline cannot act like a Brønsted-Lowry base

D. Proline cannot be amphoteric.

213. What is the mode of inheritance of the genetic disor-der depicted in the following pedigree chart?

A. Huntington’s disease, an autosomal dominantdisease.

B. Tay Sachs disease, an autosomal recessive dis-ease

C. Retinitis pigmentosa, a X-linked dominant dis-ease.

D. Duchenne muscular dystrophy, a X-linkedrecessive disease.

214. A mature human sperm cell contains 23 chromo-somes. How many chromosomes are present in thesecondary spermatocytes arrested in metaphase ofmeiosis II?

A. 23 (22 somatic plus either one X or one Y chro-mosome)

B. 24 (23 somatic plus either one X or one Y chro-mosome)

C. 46 (44 somatic plus either XY or XX chromo-somes)

D. 92 (88 somatic plus either two XY or two XXchromosomes)


Normal female

Affected female Affected male

Normal male

C O

HO

HN

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