7 r All Answers Small

7/30/2019 7 r All Answers Small

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Test 7R P Physic 1 - 77

1 26.

2. 27.

3. 28.

4. 29.

5. 30.

6. 31.

7. 32.

8. 33.

9. 34.

10. 35.

11. 36.

12. 37.

13. 38.

14. 39.

15. 40.

16. 41.

17. 42.

18. 43.

19. 44.

20. 45.

21. 46.

22. 47.

23. 48.

24. 49.

25. 50.

51. 76.

52. 77.

53.

54.

55.

56.

57.

58.

59.

60.

61.

62.

63.

64.

65.

66.

67.

68.

69.

70.

71.

72.

73.

74.

75.


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Test 7R Verbal 78 -137

78. 103.

79. 104.

80. 105.

81. 106.

128.

82. 107.

129.

83. 108.

130.

84. 109.

131.

85. 110.

132.

86. 111.

133.

87. 112. 134.

88. 113.

135.

89. 114.

136.

90. 115.

137.

91. 116.

92. 117.

93. 118.

94. 119.

95. 120.

96. 121.

97. 122.

98. 123.

99. 124.

100. 125.

101. 126.

102. 127.


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Test 7R Biology 140 - 216

140. 165.

141.166.

142. 167.

143. 168.

144. 169.

145. 170.

146. 171.

147. 172.

148. 173.

149. 174.

150. 175.

151. 176.

152. 177.

153. 178.

154. 179.

155. 180.

156. 181.

157. 182.

158. 183.

159. 184.

160. 185.

161. 186.

162. 187.

163. 188.

164.

.

189.

190. 215.

191. 216.

192.

193.

194.

195.

196.

197.

198.

199.

200.

201.

202.

203.

204.

205.

206.

207.

208.

209.

210.

211.

212.

213.

214.


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7R Key


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EXPLANATIONS for test 7R

1. A nitrogen atom has 3 single electrons and 1 lone pair. Hydrogen has one electron.The structure in C correctly shows each nitrogen with three bonds and a one lone

pair. Each atom in this molecule has a full outer shell of electrons and allelectrons are present.

2. Equation 1 shows that the Raschig process requires the reaction of 2 molesof ammonia to form 1 mole of hydrazine. The molar mass of ammonia is 17g/mol (14 + 1 + 1 + 1). Therefore 34 g of ammonia is required to form 1 mole of

hydrazine.

3. The passage states that the formula for hydrazine hydrate is N2H4H2O. Theformula weight for hydrazine is 32 g/mol (14 x 2 + 4 x 1). The formula weight for

hydrazine hydrate is 50 g/mol (32 + 2 x 1 + 16). The percent by weight of

hydrazine in the hydrate would be 32.0/50.0 x 100%.4. The reaction shows the formation of hydrazine from its elements. The value of

Hf for a substance is the enthalpy change when one mole of that substance isformed at 1 atm pressure and 25C from the elements in their stable states at that

pressure and temperature. Table 1 shows that Hf for hydrazine is 50.6 kJ/mol,therefore, the enthalpy change for the reaction shown would be 50.6 kJ/mol.

5. The basicity constant is a measure of the strength of a base. It is the equilibriumconstant for the reaction of the base with water. The lower the value of Kb, theweaker the base.

6. In order for a reaction to be a spontaneous process, the value forGo must be lessthan 0.

7. Because there are 3 reactant moles, all liquids, and 7 product moles, all gases, theentropy increases in this reaction. Gas molecules have more freedom and

randomness, and therefore higher entropy.8. Since the ions are thousands of times more massive than the electron, answer B is

justified (the hydrogen ion is the lightest ion and is nearly 2000 times more

massive than the electron). An ion with so much mass compared to an electron

will not be able to respond quickly because of its inertia.

9. The potential energy of an oscillatory motion is kx2 where x is the displacement.Since the maximum displacement occurs at A and C, answer D is justified.

10.The frequency is given by 9n0.5. With n = 1018, n0.5 = 109. Thus, frequency is9 *109, which is answer C.

11.Wavelength is given by speed/frequency = 3 *107/109 or 3*10-2 m. This is thesame as 3 cm or answer A.

12.This is basically a conservation of energy question. As the electrons move from Ato B they convert potential energy into kinetic energy (mv

2) and gain velocity


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and hence momentum (mv) as they do so. This momentum is just enough to allow

the electrons to go from B to C; i.e. the kinetic energy reconverts to potentialenergyjust equal to the amount of potential energy at point A.

13.This is basically a conservation of energy question. As the electrons move from Ato B they convert potential energy into kinetic energy (mv

2) and gain velocity

and hence momentum (mv) as they do so. This momentum is just enough to allowthe electrons to go from B to C; i.e. the kinetic energy reconverts to potential

energyjust equal to the amount of potential energy at point A. As the electrons

move from A to B they convert potential energy (kx2) into kinetic energy

(mv2), where x is the displacement from point B. It is conservation of energy.

14.The passage states that silicon cannot be purified by electrolytic techniques. Thesetechniques involve isolating silicon from silicate minerals by decomposing the

minerals with an electrical current. It would follow that the silicon could not bepurified by electrolytic techniques if the minerals do not decompose easily.

15.Silicon is the fourth element in the third row of the periodic table and has 14electrons. The first 10 electrons would have the same electron configuration as Ne.

The next 2 electrons would fill the 3s orbitals and the last 2 electrons would beginto fill the 3p orbitals following Hunds Rule (electrons will not pair up until each

orbital in that sublevel has 1 electron.). The unpaired electrons have parallel spins.

16.According to VSEPR theory, 4 electron pairs around an atom will result in atetrahedral geometry.

17.Elements in the same group share chemical properties. Because potassium is aGroup 1 element, one would assume that sodium, another Group 1 element wouldbe the best substitute.

18.Van der Waals forces are weak intermolecular attractive forces. The relativelylow boiling point of the SiCl

3H indicates that the intermolecular forces are not

strong and are most likely van der Waals forces.

19.Fractional distillation can be used for purification when the components to beseparated have different boiling points.

20.A1 and A2 represent the nuclear masses of the fragments of fission. This is givenby the sum of their proton and neutrons. Since the reaction started with 236

nucleons and three neutrons were 3 = 233 mass units ortaken away the sum ofthe fragments must contain 236 nucleons.

21.This reaction is exactly a reproduction of the statement of beta decay as given inthe stem. We see the new nucleus, a beta particle (an electron) and a neutrino. The

new nucleus is one atomic number higher because of the emission of the electronleaving an extra proton in the nucleus.

22.The relative rate of decay for Ra compared to Pu is the inverse ratio of their half-lives or 24000/1600 = 15. This is answer B.


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23.The total volume held by 106 kg of ash would be (106 kg/1000 kg/m3) = 1000 m3.This volume is held in a cube 10 m on a side since (10 m)

3= 1000 m

3. This is

answer B.

24.The value for E

o

cell is equal to the sum of E

o

of the half reactions. -1.23 + 0.34 = -0.89 V.

25.The ideal gas law makes the assumption that molecules have no volume. Thisassumption is adequate when the gas is at 1 atm, but when the pressure isincreased to 500 atm the volume of the gas molecules is no longer negligible.

26. velocity.Power P is force Since speed v is fixed we must compare the forces Fand Ft. The force is the coefficient of friction between tiresmg, where on the

level road F is by notingand road. We can find

Now the force required to be overcome in going uphill Ft is

The power in t his case, Pt, is Ft v. The extra power needed is then Pt minus theoriginal power P or:

Since cos 10 1,o

This is answer D.

27.Light slows down because the index of refraction in the glass is greater than in theair. The index is a measure of the ratio of the velocity in air to the velocity in the

medium. For sound the speed becomes greater because the speed of sound in asolid is much greater than in air (the glass has stiff rigid bonds which gives rise toa speed more than 10 times greater than in air).

28.The passage states that the reaction is zero order with respect to bromineindicating that bromine is not involved in the rate determining step. If the reaction

proceeds by the same mechanism with chlorine, then the reaction with chlorine


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will have the same rate as it does with bromine because it would be zero order

with respect to chlorine.

29.The passage states that the reaction is zero order with respect to bromine,therefore bromine can be removed from Equation 2. A comparison of the resultsfor Experiments 2, 4 and 6 (all with acetone concentrations of 0.80 M) shows that

after dividing the rates of the reactions by the rate constants, the values obtained

are directly proportional to the H+

concentration indicating the reaction is firstorder in H

+.The passage states that the reaction is zero order with respect to

bromine, therefore bromine can be removed from Equation 2. A comparison of

the results for Experiments 2, 4 and 6 (all with acetone concentrations of 0.80 M)shows that after dividing the rates of the reactions by the rate constants, the values

obtained are directly proportional to the H+

concentration indicating the reaction

is first order in H+.

30.The passage states that the reaction is zero order with respect to bromine,therefore bromine can be removed from the expression. If the reaction is firstorder with respect to acetone and hydronium ion, then a = 1 and c = 1.

31.The passage states that the density of acetone is 0.791 g/mL and the molar mass is58 g/mol. The molarity of pure acetone can be calculated as follows:

(0.791 g/mL)(1000 mL/L)(1 mol/58 g) = 13.6 mol/L

32.Light in the visible region of the spectrum ranges from approximately 400 nm to700 nm. The next region of light, below 400 nm is the ultraviolet region.

33. This is found as the difference between 894 MHz and 824 MHz since these aregiven as the upper and lower frequencies. This is 70 MHz and is answer C.

34.Since power P is current I multiplied by voltage V, V = 12 Volts, and themaximum power is 3 watts, then the current I must be 3/12 or 0.25 A. This is

answer C.35.This answer is implied by the passage. The conversations must be on different

frequencies to be unique and so no two frequencies can be used by different

phones at the same time.36.Here we must calculate P/r2. The maximum value occurs for answer D. The

intensities are:

A. (0.6/4) W/mile2

= 0.15 W/mile2


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B. (0.6/9) W/mile2

= 0.067 W/mile2

C. (3/25) W/mile2

= 0.12 W/mile2

D. (3/16) W/mile2

= 0.19 W/mile2, making D the key.

37.Light is a transverse wave with its electric and magnetic fields oscillating at rightangles to the propagation vector where as sound is a longitudinal pressure wave.

This comes from prior knowledge brought to bear on the problem. Answer A

correctly states the result.38.The two plates of the capacitor collect charges of opposite sign. As more charge

arrives it is harder and harder to fill the plates until finally an equilibrium occurs,

thus C is correct.39.As the capacitor discharges the voltage across it falls, thus to maintain a constant

current, R must be proportionately reduced. This is so from Ohms law, I = V/R.

To keep I fixed, R must fall with V. This is answer B.40.Since energy is lost by heating the small resistor, r, the energy stored in the

capacitor must be less than the work done by the battery during the chargingprocess. The battery supplies the energy for both processes and answer B is

justified.41.The capacitor charges up and stores energy in the electric field between the places.

The energy stored is CVc2, where Vc is the voltage across the capacitor. The

battery is the source of energy for the circuit and thus is a store of energy. Theresistor is not a storage device for energy and answer C is the correct answer.

42.With 12 Volts initially across the capacitor during its discharge (the capacitor willcharge to the battery voltage of 12V) and a current of 0.002 A as found in

Figure 2, then the initial . This is answerresistance R must have been

R = V/I = 12/0.002 = 6000 D.

43.The rate law for Reaction 3 is second order with respect to hydrogen ion. At a pHof 1 the hydrogen ion concentration is 1x10

-1. When the pH is increased to 2, the

hydrogen ion concentration is 1x10-2

. Because all other conditions remain thesame, the rate is decreased: (1 x 10

-2)

2/(1 x 10

-1)

2or 1 x 10

-2times. The rate would

therefore be (1.0 x 10-2

M/s) x (1 x 10-2

) or 1 x 10-4

M/s.

44.No kinetic information is given for Reactions 1 and 2, only equilibrium constants.45.Reaction 1 requires that a reaction takes place between two anions which would

experience electronic repulsion due to their negative charges. Protonation of theoxygen would generate an electrically neutral species and the repulsion forces

would be reduced.

46.The passage states that the reaction of H218O and SO3 is fast. Singly labeled SO4-2would be prepared most quickly by reacting the unlabeled SO3 and the labeled

H2O.


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47.In this reaction the oxygen is transferred from the chlorine to the nitrogen. Thetransition state shown in Foil C is the only transition state that indicates the bondbetween the chlorine and oxygen breaking and a new bond between the oxygen

and nitrogen forming.

48.The passage states that the Sequences I and III in Reaction 3 are fast andSequence II is slow. This indicates that Sequence II would have the highestenergy barrier, as is shown in the energy diagram in Foil B.

49.A substance boils when enough heat has been supplied to overcome theintermolecular forces. The fact that ammonia has a higher boiling point thatphosphine indicates that ammonia requires more heat to overcome the

intermolecular forces than does phosphine and therefore the intermolecular forces

in ammonia are stronger than those in phosphine.50.Density is mass/volume. The densities of the four objects are:

A.(1.5/0.50) = 3.0 g/cc

B.(3.0/0.75) = 4.0 g/ccC.(4.5/1.00) = 4.5 g/cc

D.(6.0/1.50) = 4.0 g/ccThus, answer C with 4.5 g/cc has the highest density.

51.Chlorine needs 1 electron to fill its outer shell.52.The ammonium ion is an acid. It is a proton donor.53.This is a Snell Law problem:

where the ns are the indices of refraction. Taking the index of refraction of air to

be nearly 1 then:

This is answer B.

54.According to the information in Table 1, the solution would contain 37.7 gPb(NO3)2/100 mL H2O. The molality (mol solute/kg solvent) can be calculated as

follows:(37.7 g Pb(NO3)2/100 mL H2O) x (1000 mL H2O/1 kg H2O) x (1 mol

Pb(NO3)2/331 g Pb(NO3)2)

= 1.14 mol Pb(NO3)2/kg H2 O = 1.14 m.55.The passage states that the freezing point depression constant for water is Kf= -

1.86oC/m. A solution that is 10.75 m ethylene chloride would lower the freezing

point of water by 1.86oC/m x 10.75 m or 20.0

oC. The freezing point of water is

0

o

C, so the freezing point of the solution would be 0

o

C - 20.0

o

C or -20.0

o

C.56.The freezing point depression depends on the number of particles in the solution.A 0.1 M solution of lead nitrate would have a particle concentration of 0.3 M (1mole of lead ions and 2 moles of nitrate ions for each mole of lead nitrate) while a

0.1 M solution of ethylene glycol would have a particle concentration of 0.1 M.The lead nitrate would therefore have a 3-fold greater effect on the freezing point

of water.


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57.Ethylene glycol has two alcohol functionalities making it a polar molecule. Wateris also a polar molecule. Table 1 shows that ethylene glycol is infinitely soluble inwater at both temperatures. Thus the like dissolves like generalization applies

while temperature dependence of solubility generalization does not.

58.The interstitial fluid is hypertonic, meaning that the concentration is greater in theinterstitial fluid than in the cellular fluid. There will be an osmotic effect becausethe cell wall is a semi-permeable membrane. Solvent will pass through the cell

wall from the cell to the interstitial fluid resulting in an increase in the

concentration of the cellular fluid.59.Table 1 shows that lead nitrate has a solubility of 37.7 g/100 mL H 2O at 0oC. The

solution described in the stem would be saturated with 1.3 g (39.0 g - 37.7 g) of

undissolved lead nitrate remaining.60.The mole fraction can be determined as follows:

10 g Pb(NO3)2 x (1 mol Pb(NO3)2/331 g Pb(NO3)2) = 0.03 mol Pb(NO3)2

90 g H2O x (1 mol H2O/18 g H2O) = 5 mol H2OMole fraction = 0.03 mol Pb(NO3)2/(0.03 mol Pb(NO3)2 + 5 mol H2O) = 0.006

61.Since acceleration is the rate of change of velocity, Case II will have the loweracceleration (or deceleration). It will be in the ratio of the inverse times or

(0.1/0.25) or 0.4. This is answer B.62.Each car has kinetic energy of mv2. Thus the total kinetic energy transformed

into heat and deformation is 2 (mv2) = (1000)(20)

2= 400,000 J. This is answer

B.

63.Certainly the change in the coefficient of friction as one goes from soft rubber tohard would not influence the required tire pressure. Thus answer D is correct in

that we expect this prediction not to hold.

64.This answer follows directly from the passage. Without the spring the collisiontime will be short making the deceleration and the resulting force large. The

spring absorbs some of the energy and is set into oscillatory motionthis will

increase the net time of the collision. Thus the answer is A.

65.The passage tells us that during each second Car A travels 30 m and Car B travels20 m. To make up 100 m the two cars must travel 10 seconds. This is answer D.

66.Since momentum is conserved and is given by mass multiplied by velocity wehave mv + MV = (m + M) Va, where v and V are the initial velocities of cars A

and B and Va is the velocity of both after the inelastic collision. So


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This is answer C.

67.Since we would expect the quake information to propagate in all directions, itdoes not support the coincidence hypothesis to learn that subsequent quakes

occurred in all directions. The other three answers all stress the possibility of

coincidence.

68.Lasting deformations go as (L/d)3 according to the passage. Thus for two differentvalues of d, d1 and d2, the ratio of lasting deformations will go as (d2/d1)

3. This

value will be (4/16)3

= (1/4)3

= 1/64. This is answer C.

69.Answer A certainly makes sense qualitatively. The relatively small triggerunleashed a quake that was basically ready to go with a small provocation.Answer B sounds good but the passage argues against elastic oscillations causing

lasting deformations. Answers C and D make no sense and are wrong. Thus A is

the best answer.70.The speed of a wave v is given by its wavelength divided by its period T:

The order of magnitude is then thousands of meters per second or answer B.

71.The Doppler Effect will cause a bunching or squeezing of the waves moving withthe rupture and an elongation of the waves opposing the rupture. This is answer C.

72.The difference in pressure in a fluid on Earth is:(change in g (density of fluid) height) = (1000)(10)(0.25) = 2500 N/m

2

This is answer C.

73.The reaction equation shows the reduction of H+ by Cd. Because the H+ acceptsthe electron readily from Cd, it can be determined that H

+has the highest electron

affinity.

74.According to the relation given in the passage, the energy of an electron in orbitn = 3 is less negative or greater than the energy in orbit n = 2. Thus energy is

required to make the transition from n = 2 to n = 3 and the atom gains energy.Answer D states precisely this and only D is consistent with this result.

75.To find the relative refractive index to air one needs both the incident andrefracted angles. Since the angle of incidence is equal to the angle of reflection wewill know the angle of reflection. We still must know the angle of refraction and


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this is answer B. None of the other answers will allow one to know the angle of

refraction.76.A faraday is equal to one mole of electric charge. Because each aluminum ion

gains 3 electrons, 0.1 faraday of charge will reduce 0.1/3 moles of aluminum, or

0.033 moles of aluminum.

77.The indicator will change color over a specific pH range. The range at which thecolor change takes place depends on the point at which HIn is converted to In

-,

and this depends on the pKa of the indicator.

78.Changes brought on by human judgment are natural.This thesis is implied or stated by the author throughout the passage, including theview that such adaptation is natural to a peculiarly human evolution: If we

believe that all life shares a certain quality of sensitivity, or self-awareness, then

Homo sapiens was an astonishing and wholly unpredictable leap forward in thisrespect. This view is reinforced by the authors point about the superiority of

cultural over genetic adaptation: When human beings encounter newcircumstances, adaptation rarely depends on which individuals are genetically

best suited to adjust. No, human beings tend to cut the loop short by noticingthe new, puzzling over itattempting to find out immediately what is edible,

combustible, domesticable. The author sets this view against the view of

human presence is a sort of monolithic [natural] disaster that is making theworlds natural continuance impossible.

79.The author states that the human capacity for reasoned judgment sets it apart fromother creatures: What seems simple to us is far beyond them. The authorelaborates by focusing on human problem-solving and inventiveness as a means

of adaptation. By reasonable implication, the author would say the same for aspecies with greater capacities than humans.

80.While the author acknowledges the concerns about the rates of extinctions, sayingthese are what alarms so many life historians, the author does not share theiralarm, instead asserting that change, one of the most reliable constants, occurs

rapidly because of human agency: I dont think [North America] is a poorer

place now than it was twenty thousand years ago. Compared with other creatures,

its almost as if we move so fast that we are invisible [to other creatures], andthey are still trying to pretend that the world is the same as it was before we

arrived. The speed of human adaptability accounts for humans wholly

unpredictable [evolutionary] leap forward, according to the author. This impliesthat human adaptability is a natural occurrence.

81.The superiority of human cultural adaptation over genetic adaptation is a keyfeature of the authors central argument that humans are conscious agents ofchange on this planet. It follows that the author would focus on human

inventiveness as the key to survival on Mars.

82.The author emphasizes how life historians support this particular argument:What alarms so many life historians is not that extinctions are occurring but that


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they appear to be occurring at a greater rate than they have at all but a few times

in the past.83.In discussing cultural adaptation, the author states: When humans encounter

new circumstances, adaptation rarely depends on which individuals are

genetically best suited to adjust. Instead, humans adapt by noticing the new,

puzzling over it, telling their friends, and attempting to find out immediatelywhether it is edible, combustible, domesticable.

84.The author is fairly direct on this point; after questioning the belief of manypeople that these changes [brought about by human cultural adaptation] are oftenfor the worse, the author states: The more convinced we are that our species is a

plague, the more we are obliged to yearn for disasters. The author is convinced

that human potential allows for rapid and beneficial adaptation: Consciousness.Mind. Insight. Here are qualities that, if not exclusively human, seem appallingly

rudimentary elsewhere. Plainly, our planet contained vast opportunities for

creatures willing to shape it consciously toward their ends. The author stronglyimplies that only humans took this opportunity in the form of cultural adaptation.

85.After stating that no artist prior to Czanne had attempted to view the worldobjectively, and pointing out how several periods in art history had attempted to

make art imitative, the author points out that there always intervened between

the visual event and the act of realizing the vision an activity which we can onlycall interpretative. The author elaborates on this by stating the differences

between sensual perception and art: This intervention seemed to be made

necessary by the very nature of perception, which does not represent to the sensesof flat two-dimensional picture with precise boundaries but a central focus with a

periphery of vaguely apprehended and seemingly distorted objects. The authordiscusses the role of imagination and intellect being like a map in helping the

artist interpret perceived reality by means of, for example, a system of

perspective, and then states: One might conclude from the history of art thatreality in this sense is will-o-the wisp, an actuality we can see but never grasp.

Interpretation, for the artist, becomes part of the act of seeing.

86.The author establishes the central thesis in the first paragraph, citing the single-minded determination of [Czanne] to see the world objectively. The authordevotes much of the remainder of the passage to discussing how much of art

previous to Czanne represented an interpretation of reality by bringing extra-

visual faculties such as imagination and intellect into play. Czanne by seeingthe world as object attempted to succeed in this where [his predecessors] had

failed.

87.The author states this idea outright: Great revolutionary leaders are people with asingle and a simple idea, and it is the very persistency with which they pursue this

idea that endows it with power.

88.The author says: [Czannes] immediate predecessors, the Impressionists, hadseen their world subjectivelythat is to say, as it presented itself to their senses in


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various lights, or from various points of view. Each occasion made a different and

distinct impression on their senses..

89.The context of the phrase indicates that it refers to the inability of artists beforeCzanne to effectively depict reality: One might conclude from the history of artthat reality in this sense is a will-o-the wisp, an actuality we can see but never

grasp. Prior to this statement, the author had discussed how reality had eluded

artists before Czanne, including through the use of the system of perspective:like a map, [perspective] serves to guide the intellect; perspective does not give

us any glimpse of the reality.

90.The author asserts Greek and Roman art was possessed of a desire to representthe world as it really is without offering specific examples or discussion ofexactly how Greek and Roman artists attempted this.

91.The key to the authors point about Czanne is the influence Czannespersistence exerted on modern art: There is no doubt that what we call the

modern movement in art begins with the single-minded determination of a Frenchpainter to see the world objectively. The author, referring to Czanne, discusses

the persistence of great revolutionaries in pursuing an idea. Near the end of the

passage, the author reinforces this point, saying, But Czannedid not despairof succeeding where his predecessors had failed.

92.The author asserts in the beginning of the passage that Czanne founded themodern movement with his single-minded determinationto see the worldobjectively and later implies that Czannes contribution to art was revolutionary.

This discovery would represent a strong challenge to the authors premise.93.The argument that extra-visual faculties enabled artists to interpret their

perception of the world through art is one of the most fully developed in the

passage. The author discusses the role of imagination in creating an ideal spaceoccupied by ideal forms and the role of intellect in creating a scientific chart, a

perspective in which the object could be given an exact situation. The author also

says that these faculties helped guide the intellect but did not grasp objective

reality.

94.The author is explicit on this point, drawing a direct analogy between maps andthe system of perspective: But a system of perspective is no more an accurate

representation of what the eye sees than a Mercators projection is what the worldlooks like from Sirius. Like a map, it serves to guide the intellect.

95.The poetic qualities of the passage occur in the emphasis on vivid physicaldescriptions and imagery that appeal to the senses or the emotions rather than

reflect scientific accuracy: this sunflower became incredibly beautiful, subtly


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turning its face daily, always toward the light, its black center alive with a deep

blue light, as if flint had sparked an elemental fire there; bees with legsfat with pollen, grasshoppers with clattering wings and desperate hunger; I

never learned the sunflowers golden language. The author observes both

changes and orderly occurrences, one example being the bamboo that flowers

once a century on the same day no matter where they are located.96.One example in the passage where cyclical regularity occurs is with the bamboothat blooms once a centuryall plants, no matter their location, bloom on the

same day by some special hidden mode of communication. The author observes:Some current we cannot explain passes through this primitive life. Each with a

share of communal knowledge, all are somehow one plant.

97.Prior to describing the sandstorm and the dead horse, the author observes:Changes also occurred in the greater world of the plant. The sandstorm

particularly had an impact, drying out and blowing away the petals before another

change came: Then birds arrived to carry the seeds to the future. The author innon-judgmental fashion simply observes these changes as necessary, especially

birds carrying the seeds away, with the implication being that this is a means bywhich new flowers are planted.

98.Nowhere does the passage suggest humans will satisfy their curiosity about nature.The tone of the passage reflects the authors sense of wonder at the variety and

tumult of life in its changing and recurring patterns, especially the more aware a

person becomes. This is reflected in the following: Sometimes you can hear thelanguage of the earth. Once, in the redwood forest, I felt something like a

heartbeat, a hardly perceptible current that stirred kinship and longing in me.

The final paragraph, especially, touches on the notion that human wonder andcuriosity before the natural world will never cease, but is passed on though the

ages: Without written records, they registered the passage of the gods of night,noting the fine details of the world around them and the immensity above them.

The author shares this sense of wonder with ancestors: Behind me, my ancestors

say, Be still. Watch and listen. You are the result of the love of thousands.

99.The emphasis in the passage is on symbiotic relationships: the sunflower as a hostto various insect species, birds carrying away the seeds of the sunflower. Thefurther implication of this is that these symbiotic relationships in nature continue

even with human land use. Another implication in the passage and in final

paragraph is that humans can know, appreciate, and become a part of the naturalworld and its symbiotic relationshipshuman awareness of these relationships

may even be the key to their continuation.

100. The major emphasis in the passage, especially in the tone and attitude, isthe author observing and learning from nature, culminating in the final paragraph

with the author participating in the collective knowledge and wisdom of previous

generations: Tonight I watch the sky, thinking of the people who came before meand their knowledge of the placement of stars. Whichever road I follow, I walk

in the land of many gods. Behind me my ancestors say, Be still. Watch and

listen.


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101. The sense of unity is communicated by the authors word choice, inparticular, kinship: Once, in a redwood forest, trees, I felt something like aheartbeat, a hardly perceptible current that stirred a kinship and longing in me.

Other word choice, such as heartbeat, implies that the authors kinship is with

some of the vital life-producing currents.

102. The author supports this by explaining that Schenberg disclosed that theultimate expansion of possible relations to include the whole range ofcombinations contained in the semitonal scale demands a revaluation of every

aspect of musical language. The author further explains that the atonal

composercan take nothing for granted and that atonality merely [stipulates]the absence of a priori functional connections among the twelve notes of the

semitonal scale. Among these a priori functional connections would be the

seven-tone scale, triadic harmonic structure, andkey center the author refersto earlier.

103.

The author first states that the diatonic tonal system presupposes theexistence of specific properties of that system: a seven-tone scale, triadic

harmonic structure, a key center. The author then goes on to state thatatonality is defined as merely stipulating the absence of a priori functional

connections among the twelve notes of the atonal scale. The purpose of this

comparison is then to show how atonality largely resists the limitations ofadhering to preconceived concepts of musical organization.

104. This conclusion is implied more than once in the passage. The authorstates that a composer working within the diatonic tonal system may take forgranted the existence of specific properties of that system [such as a seven-tone

scale]. The word choice of take for granted implies that the composer assumes

those limitations whereas the atonal system implies that a composer has far morechoices: The atonal composercan take nothing for granted except the existence

of a given limiting sound world, the semitonal scale. The author alludes to a

greater range of choice for the composer later in the passage when discussing how

the general composition of an atonal work may vary greatly from one work to thenext, even in works by the same composer.

105. The absence of a priori functional connections among the twelve notes ofthe semitonal scale means that other more readily apparent structures such as

triadic harmonic structures will not be available to the listener. The idea thatatonal music will have a less readily apparent structure is implied by the statement

that the composer is still working under certain constraints such as the existence

of a certain limiting sound world, the semitonal scale.


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106. The author infers that in the atonal system the ordering is determined moreby the composers choices than by the compositional conventions of the diatonictonal system: An unambiguous ordering is assumed; but the degree to which this

ordering actually determines the general musical procedures varies greatly from

one work to another, even though they may be by the same composer.

107.

The author makes two observations revealing that the author is particularlyconcerned about the United States. The first concerns the part of U.S. work force

that is employed by low-road firms: About 40 percent of U.S. workers receive no

formal training beyond a high-school education. The second concerns U.S.competitiveness in particular: For the United States to compete in an eventual

global economy based on skilled workers and quality products, additional

employer investment in training is needed now.108. The author points out that high-road firms emphasize investments in

highly skilled workers and long-term goals, both of which may delay profits and

discourage investors wanting short-term profits. The author further points out thatonly dominant firms protected from domestic or international competitors by

technological advantages, large-scale production, or government regulations canafford to invest in skilled workers and long-term goals. With this last observation,

the author is saying such a firm is going to have to grow before it can becompetitive and go public.

109. The author asserts the earning power of being able to use a computer onthe job: Workers who use computers on the job also earn more than do those of

the same education level who do not use computers at work. Moreover, theearning difference increases with the level of technological competence.

110. The author emphasizes the importance of investing in worker training inhigh-road firms and producing highly skilled employees who can react quicklyto changing technologies and markets. The author also emphasizes what kind of

investment in worker training is most desirable: Workers who receive formal

company training command higher wages than do similar workers who attend

only vocational school or receive informal on-the-job instruction.

111. In discussing the muddy road, the author specifically refers to workerswho get Some advanced education or job-related training but [are] unlikely to

enter the dynamic high-road labor market. The author later warns of this

phenomenon again in discussing job-related training: Although for a particularjob, employer-based training or vocational preparation can substitute for general

schooling, specific training degrades rapidly, and narrow skills seldom transfer

well to new job requirements.112. The author encourages policies that realize the highest returns, and, while

the author does not discuss a policy of repaying tuition, such a policy would be

consistent with the authors advocacy of putting policies in place that further


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worker training goals, for example, policies that encourage the coordination of

employer-provided training and broader schooling.

113. In discussing automated production processes, the author advocatesencouraging workers at all stages of their operation to demonstrate expertise andresponsibility. Using a computerized bulletin board to share tips with one

another is a way of empowering workers by giving them expertise and

responsibility.114. The author explains increasing disparity in earnings by how earnings

increase when computers are used at work, adding that earning difference

increases with the level of technological competence. This observation is mostconsistent with this example in instances where former low-level workers get

more sophisticated equipment and training when they move into managerial-level

positions.

115. The author, in advocating training workers for high-skilled positions,offers by way of warning the caveat that all trained workers may not benefit fromadvanced training: If the investment in workers outpaces the number of good

jobs, many very competent workers will face an employment market of many

very undemanding jobs.116. The author states that the low-road emphasizes downsizing and

outsourcing to cut labor costs, so it logically follows that a firm that emphasizes

cutting jobs is likely going to have fewer workers. This explains why there is agreater percentage of these firms in the U.S., since there are going to need to be

more of these firms with fewer workers in order to accommodate the U.S. workforce.

117. The author cites the following mortality figures: A quarter of the peopleborn in seventeenth-century France died during their first year, another quarterdied before the age of twenty, and a third quarter died by the age of forty-five.

Therefore, it follows that a person who lived to age forty and began having

children at age twenty could see 50 percent of these children die.

118. The author notes that 75 percent of all people who died did so by age 45.The author further notes that by 1980 average life expectancy was 73.6 years,which was mainly due to success in reducing infant, childhood, and maternal

mortality. To put it another way, many more people now live past age 60, which

is why the association of death with old age has become a recent phenomenon.

119. The author states that advertisements for retirement living made promisesof the good life and reflected a sense of optimism and common goals: Lured by

glossy advertisements depicting a life of warm friendships and endless pleasures,

many retirees welcomed these new complexes as a new adventure. The author


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later notes that surveys of elderly showed that these promises largely proved to be

true as the elderly found the friendship and leisure in these retirementcommunities that was advertised. Therefore, the directors statement supports the

optimistic assumptions made by the author and the fact that many retirement

communities have evolved from mere developers tracts into communities with

traditions of their own.

120. The emphasis in the passage is that the current rate of longevity isunprecedented and that the comparison between now and seventeenth-century

France documented this. The authors thesis is that the appearance of retirement

communities is a kind of frontier: Old age is hardly new, but for an entiregeneration to reach old age with its membership almost intact is new. This

comparison supports that thesis.

121. The author, in discussing longevity, shows that people are not livingappreciably longer in actual years but that more people are living into old age and

that life expectancy depends on health in earlier years. This statistic underscoresthis crucial difference between life expectancy, which has increased dramatically,

and longevity, which has increased comparatively little.

122. By referring to the school readiness theory of education as a usualpracticeof treating learning as an abstraction, the author is implying that this

theory is generally accepted. The author points out that the outlook behind this

theory was opposed by educational theorists Jean Piaget and A.L. Gesell whoadvocated developmentally appropriate, personally meaningful education for

children, a view supported by observers of modern education: Most modernobservers of children think that if a task is developmentally appropriate and has

personal meaning for a child, it is approached as a pleasing challenge, not a

struggle. The author implies that any educational theory that goes counter to thekind advocated by Piaget and Gesell is ineffective.

123. The author states: In the literature promoting their approach, theadvocates of generalized readiness are clearly directing their appeal to school

administrators.

124. The author points out: Developmentally appropriate instructionappearsto be a hard sell to decision makers concerned with uniformity. This statement

implies that uniformity is more convenient than an individualized approach, with

the added benefit of higher percentages on standardized tests.125. This analogy is most apropos because the author contends that, much like

a form letter, school readiness is too impersonal and standardized whereas

developmentally appropriate instruction, much like a personal note to a friend, isfocused on the individual needs of children and is designed to be personally

meaningful to them.


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126. The author discusses the importance of developing a test to validatecurricular reforms and educational effectiveness.

127. .The author would likely doubt the accuracy and quality of the report sincethat is how the author reacted to efforts to introduce school readiness. The author

also devotes the first two paragraphs to explaining why reformers should take care

to prove their reforms are needed and credible.128. The objector does not say that politicians are better decision makers thananyone else, so the argument that politicians could decide anything is relevant.

The author reinforces that argument by saying: A government is made up ofindividuals who are fundamentally similar to me, and to err is human applies to

us all. The author concedes that a government leader or official may be more

well informed or expert in a particular issue. Therefore, an individual could acceptthe decision on the basis that the decision is likelier to achieve a better outcome,

but even the decision to decide whether the government is right or wrong still is

the responsibility of the individual.129. The author commits somewhat of a logical fallacy by asserting that it is

impossible to surrender responsibility. One could do so freelyalthough theauthor is right in saying that once you make that choice you have enslaved your

will to some elses will. In the case of someone with the hypotheticalpsychological condition referred to in the question, a person surrenders

responsibility involuntarily, because that person would be incapable of making

the decision whether to be responsible or abdicate responsibility; nonetheless, thatperson surrenders it.

130. This theme runs throughout the passage. The author states: You cannothand over your autonomy willy-nilly tothe government or any one else. Theauthor also states: No government, no body of people, no position, no individual

can have moral authority over any individual. The author also points out thatthe final arbiter is the individual, even if the government has good reason to

require a particular behavior.

131. This hypothetical finding theoretically represents a strong challenge to theassertion that the individual is the final moral arbiter, even if that assertion

remains a valid argument, because it greatly increases the individuals burden of

proof and, hence, individual responsibility for decisions.

132. Even if people drive on different sides of the road in different countries,the central thesis is unchanged by knowing this. The author already gives theexample of driving on the left side of the road; therefore, introducing the example

of people driving on the right side of the road in another country neither weakens

nor lends further support to the central thesis than is already in the passage. Atmost this new information is simply a variation on the exact same argument. The

decision to drive on the right side of the road in a country where it is the law to do

so has the same obvious benefits in that country as it does in a country where it isthe law to drive on the right side of the road. A responsible individual would obey

the law because of these obvious benefits, not because the government mandates

driving on the left side, or right side, of the road.


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133. Even if people drive on different sides of the road in different countries,the central thesis is unchanged by knowing this. The author already gives the

example of driving on the left side of the road; therefore, introducing the example

of people driving on the right side of the road in another country neither weakensnor lends further support to the central thesis than is already in the passage. At

most this new information is simply a variation on the exact same argument. The

decision to drive on the right side of the road in a country where it is the law to doso has the same obvious benefits in that country as it does in a country where it is

the law to drive on the right side of the road. A responsible individual would obey

the law because of these obvious benefits, not because the government mandatesdriving on the left side, or right side, of the road.

134. The ethnic conflict in Bosnia reflects Gibbons view of history as well asview of human nature that extends from his historical analysis: [Gibbon]instructs us that human nature never changes and that humanitys predilection for

factionalism, augmented by environmental and cultural differences, is thedeterminant of history.

135. According to the author, Gibbon was a conservative along the lines of hiscontemporary, Edmund Burke, who saw humankinds best hope in moderate

politics and flexible institutions that would not become overbearing. The authoralso observes that a state or an empire can endure only if it generally limits itself

to adjudicating disputes among its citizens. The role of the U.S. Constitution,with its checks and balances among the three branches of government, is to limit

government in this way.

136. Ethnic diversity, in Gibbons view, is one of the destabilizing factors inhuman history. Therefore, a stable society that is ethnically diverse would mostchallenge Gibbons viewhis view might hold up if this society were explained

by a system of limited government that adjudicated these ethnic differences.

137. The role of Milan and Nicomedia as functional capitals shows howhistorical changes occur gradually, because these roles came decades before theformal division of the Empire into western and eastern halves and almost two

centuries before Rome officially ceased to be the imperial capital.


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140. According to Theory II, the metabolic rates of mammals are directlyproportional to the rate of generation of free radicals. The information presentedin the item stem, comparing humans, rats, and mice indicates that metabolic rate

for humans is at 25cal/g/day, that of rats is at 150 cal/g/day, and that of mice is

greatest at 180 cal/g/day. Thus the generation of free radicals, and subsequent

evidence of a free-radical-induced DNA damaged product in urinary output, isconsistent with the graph shown in foil A. Foil A shows a direct relationship

between metabolic rate (x-axis) and the urinary output of a free-radical-induced

DNA damaged product (y-axis). This is consistent with Theory II.

141. According to Theory II, aging and cell death is caused by theaccumulation of damaged DNA, RNA, and other molecules in the cell. This

damage is caused by free radicals. This theory also indicates that addition of

antioxidant vitamins, such as Vitamins C and E, can reduce the amount of damagecaused by free radicals, and therefore slow the rate of aging and cell death.

Additionally, according to Theory I, connective tissue cells are known to divide atotal of 50 times before dying, regardless of the conditions and treatments.

Assuming that connective tissues have already undergone 30 divisions prior totreatment with Vitamin E, Theory I would be supported if the cells undergo 20

more divisions before dying, but Theory II would be supported if the cells

undergo more than 20 additional divisions. If the cells undergo 40 divisions aftertreatment, this would clearly support Theory II.

142. According to the item, the female octopus broods her eggs, but eats lessthan normal while caring for them, then dies after the eggs hatch. If a certainendocrine gland is removed, the brooding behavior is eliminated, so the female

resumes regular feeding and her life cycle is extended. This provides the strongest

support for Theory I because it shows that various characteristics of theorganisms life (brooding and feeding behavior) are hormonally controlled. Thus,

removing the endocrine gland, and source of hormones, can alter the behavior and

lifespan of the organism.

143. The item asks the examinee to identify the process that would not lead tofree-radical-induced aging. According to the passage, Vitamins C and E remove

free radicals, thus rendering them harmless. Thus, Vitamins C and E would not

facilitate aging caused by free radicals.

144. According to Theory II, lifespan is proportional to metabolic rate, andmetabolic rate can be reduced somewhat by limiting dietary intake. Thus,

supporters of Theory II would predict that the rats in the fasting group would

outlive the rats in the fed group by some finite amount. The results presentedunder Theory II indicate that rats with a minimal diet live approximately 60

weeks longer than rats that are fed more food.


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145. According to the passage, Sarah was in excellent physical condition priorto her trip to the Caribbean Sea to go skin diving. After her first diving experience,

she noticed an elevated pulse rate and ventilation rate. The most likely

explanation for her bodys response was the activation of her sympatheticautonomic nervous systemthe fight or flight response caused by adrenaline.

146. According to the passage, Sarah went skiing in the mountains of Colorado.At first, she noticed an elevated pulse rate and ventilation rate. As the weekprogressed, these rates dropped, but were still higher than usual. This prolonged

increase in heart rate and breathing rate was most likely the cause of hypoxia

(insufficient oxygen to the body cells) caused by insufficient blood hemoglobin tosupply oxygen for exercise at the low oxygen pressure found at high altitudes.

147. According to the passage, Sarah was in excellent physical condition priorto her trip to the Caribbean Sea to go skin diving. After her first diving experience,she noticed an elevated pulse rate and ventilation rate. According to the item, she

also noticed that she produced more urine than usual. The increased urineproduction can be explained by an increased blood pressure caused by adrenaline,

released in response to excitement or anxietythe fight or flight response.

148. After Sarahs accident, the physician detected myoglobin in Sarahs urine.Myoglobin is the substance that holds oxygen in the muscles and organs. The

physicians observation is consistent with an injury to muscle or organs, but not

bone.149. Control of heart rate, muscle coordination, and appetite is maintained by

the brain stem, cerebellum, and hypothalamus, respectively.

150. According to the item, Sarah noticed that her skin blood vessels wereusually constricted to conserve body heat in the cold environment of the Colorado

mountains where she went skiing. Occasionally, however, her vessels would

dilate for short periods of time to enable a sufficient supply of blood (and oxygen)

to her cells. Due to the physical exertion of skiing, her cells had an increased needfor oxygen.

151. The Cahn-Ingold-Prelog system, susbtituents are listed in order ofdecreasing atomic number. The atoms directly bonded to the chiral carbon atom

(x) are H, C, C, and N. Nitrogen has the highest atomic number and therefore theNHCHO group has the highest priority.

152. The analog of Compound 8 would undergo a Wittig reaction withPh3P=CH2 to form the double bond in Compound 1.


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153. The number of stereoisomers can be calculated using the formula 2n,where n is the number of stereocenters in the molecule. Compound 1 has 4stereocenters.

154.

The hydrogen on

-carbons c and d are most acidic. It can be determinedthat the hydrogen at carbon c is removed because alkylation occurs at this carbon.

155. The compound contains one ketone group, one ester group, and onecarboncarbon double bond.

156. According to the passage, reverse transcriptase uses viral RNA as atemplate for making viral DNA inside the cell of the host. This process is thereverse of RNA synthesis, a process that normally occurs in the host cell.

157. According to the passage, one method of combating the AIDS virus is tointerfere with the binding of the virus to the helper T cell. This is done by

producing antibodies to the gp120 proteins on the viral surface. However, the

variability of the antibody-evoking region of the gp120 protein makes it difficultfor B cells to produce antibodies that neutralize the AIDS virus in the host

because antibodies are very specific

158. AZT is effective for treating AIDS because it is missing a hydroxyl groupon the 3 carbon, a normal site for the bonding between a phosphate and sugar in

the growing DNA polymer. AZT becomes incorporated into the growing DNAchain in place of a regular nucleotide (which would have the hydroxyl group on

the 3 carbon), thereby interfering with the process of DNA polymerization.

159. Antibiotics that are effective in interfering with bacterial (but noteukaryotic) ribosomes are ineffective at combating viruses because viruses

typically lack ribosomes. Thus, a drug that interferes with ribosome functionwould have no effect against a virus.

160. According to the passage, during the infection of a helper T cell, gp120proteins of the viral coat first bind to the CD4 antigens on the cell membrane.Then the viral coat fuses with the membrane, dumping its RNA core into the cell.

Once dumped, this RNA core would be transformed into DNA by reverse

transcriptase, and the viral DNA would then become incorporated into the hostcells chromosomes until activated (replicated) at a later time. Thus, when an

AIDS virus has been incorporated into a CD4 cell, but has not yet been replicated,

the viral genetic information is located in the CD4 cells nucleusincorporatedinto the hosts DNA.


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161. The item asks which evolutionary mechanism would most likely explainthe presence in humans of CD4 receptors on the helper T cells that bind to thegp120 proteins of the AIDS virus. The most likely scenario is natural selection

favoring chance mutation(s) of the virus. This answer is supported by the

information in the passage, indicating that there is a high rate of mutation in the

gp120 protein of the virus. In addition to having a high rate of mutation, thegeneration time for a virus is quite short, which enhances the ability of natural

selection to make a difference on the viral population, even in a single generation

time for humans.

162. The item indicates that there is a virus similar to the AIDS virus, but thatthis virus infects only B lymphocytes (not the T cells invaded by AIDS virus).

The function of a B lymphocyte is to produce and secrete antibodies when it

encounters a foreign particle or substance. Thus, a virus that infects only Blymphocytes would be expected to affect the production of antibodies.

163.

This reaction is an example of the formation of a hydrazone by thecondensation of a hydrazine with an aldehyde.

164. Tertiary alcohols react much more quickly with HCl than do other types ofalcohols.

165. The graph shown in the item indicates that the concentration of cyclinrises and falls in a regular manner throughout the cell cycle, reaching a peak just

at the beginning of mitosis, gradually declining during mitosis, reaching aminimum at the end of mitosis, and gradually increasing during interphase. The

mechanism that can best account for this oscillation in the concentration of cyclin

is translation of cyclin mRNA (creating the protein from mRNA template)followed by proteolysis (destruction) of cyclin protein during mitosis.

166. According to the item, embryonic mouse cells divide every 10 hours at37

oC. Under such circumstances, and starting with a single egg, x cells would be

present after three days (or 24 x 3=72 hours). The number can be calculated by

tracking the doubling time: 1 2 4 8 16 32 64 128 256. Atthe end of 70 hours (approximately 3 days), there would be 128 cells, assuming

that each cell underwent division 10 hours after its previous division.

167. At C-5 the molecule is drawn so that the hydrogen, the group with lowestpriority, is pointing away from the viewer. The O has the highest priority,followed by C-4 and then C-6. The groups are oriented in clockwise order of

decreasing priority indicating that C-5 has an R-configuration. At C-7 again the

molecule is drawn so that the hydrogen is pointing away from the viewer. The O


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has the highest priority, followed by C-8 and then C-6. The groups are oriented in

counterclockwise order of decreasing priority indicating that C-7 has an S-configuration

168. The Grignard reagent will add a methyl group to the ketone generating atertiary alcohol.

169. The Grignard reagent is CH3MgBr prepared by the reaction of CH3Br withMg in diethyl ether.

170. The passage states that Compound 5 undergoes a regiospecific Diels-Alder reaction indicating that Compound 6 was added so that the Cl and CN

groups are present in the position in the ring as shown in Compound 7, howeverboth stereoisomers of this compound would be present.

171. Step 4 involves the addition of an acetyl group (CH3CO) to Compound 4which is an acetylation reaction.

172. The passage presents information about inflammatory bowel disease,including Chrons disease and ulcerative colitis, the latter of which is associated

with inflammation of the colon. The item asks what process would be mostdisrupted by an inflammation in the colon. Since the primary process that takes

place in the colon is absorption of water, then the absorption of water is the most

likely process to be disrupted.173. The immune system is designed to attack foreign material in the body. It

avoids attacking tissues of its own body because it suppresses cells that arespecific to its own bodys antigens (surface molecules that would otherwise

initiate an immune response).

174. If an ulcer penetrated the walls of the intestine, this would allow thecontents of the gastrointestinal tract to enter the peritoneal cavity. Membranessurround this cavity, which would prevent further transport of the gastrointestinal

contents through the rest of the body. An ulcer in the small intestine would not

allow the contents to enter the lumen because this is the normal place in which thecontents are found.

175. Assuming the genetic and autoimmune theories of inflammatory boweldisease are true, then the gastrointestinal antigen being targeted must be located

on the surface of proteins encoded by the genes for the disease. Antigens arecarried on the surface of cells, not on the chromosomes, DNA segments, or RNA.


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176. Inflammatory bowel disease appears to have a genetic component, but itdoes not show clear evidence of Medelian inheritance. This means that the traitcannot simply be recessive since, if it were, it would show Mendelian

inheritance patterns.

177. The passage describes a study in which the blood flow of participants wasmeasured before and after 60 days of exposure to one of four treatments. Thetreatments included placebo, placebo + vitamin E, fatty acid, and fatty acid +

vitamin E. The passage indicates that vitamin E is an antioxidant that reduces in

vivo oxidation of ingested fatty acids. As shown in Figure 1, the fatty acid groupshowed a reduction in blood flow by more than 40%, while the fatty acid +

vitamin E showed an increase of about 10%. The most likely explanation for the

difference in blood flow between the fatty acid group and the fatty acid + vitaminE group is that the products of fatty acid oxidation (which would be formed when

vitamin E is absent) reduce blood flow.

178. One hypothesis suggests that the decrease in blood flow to the skin resultsfrom a change in the activity in the sympathetic nerves to the skin. This

hypothesis would be supported if researchers observed a change in thenorepinephrine content of blood draining from the skin.

179. An alternative method for examining the effects of fatty acids on bloodflow would be to measure changes in blood pressure. It blood pressure weremeasured, one would predict that blood pressure would be lowest in the

capillaries, as compared to the heart, arteries, or arterioles. Pressure would beeven lower in the veins, but this option was not offered.

180. The passage describes a study in which the blood flow of participants wasmeasured before and after 60 days of exposure to one of four treatmentsaftercollecting lifestyle information abut each subject. The treatments included

placebo, placebo + vitamin E, fatty acid, and fatty acid + vitamin E. The passage

indicates that vitamin E is an antioxidant that reduces in vivo oxidation of

ingested fatty acids. To interpret the results of the passage, researchers mustassume that subjects do not alter their lifestyle (eg. eating habits) during the

course of the experiment.

181. According to the item, the fatty acid used was a 20-carbon polyunsaturatedfatty acid. The difference between saturated and unsaturated fatty acids is thatsaturated fatty acids lack carbon-carbon double bonds (because all carbons are

saturated with hydrogen).

182. Researchers collected information about each subjects age, dietary habits,etc. They made sure that skin temperature was constant during the blood flow


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measurement. The one variable that was not controlled or accounted for was skin

blood flow. This was dependent variable.

183. The passage states that alkyl groups bonded to a carbocation center maystabilize the carbocation through hyperconjugation.

184. The proton NMR shows 9 equivalent H and an additional H downfield.This is consistent with the structure of t-butyl alcohol. The 9 hydrogen on the 3

methyl groups are all equivalent.

185. If ethanol was heated with sulfuric acid the oxygen of the ethanol wouldbe protonated in the first step with the alcohol acting as a base accepting a protonfrom the acid and forming water as a leaving group.

186. The passage states that sec-butyl alcohol is the second most abundantproduct. The peak in the chromatograph with area of 3 would correspond to the

sec-butyl alcohol. The total area is (45 + 3 + 1 + 0.5 + 0.5) = 50. The percentage

sec-butyl alcohol would therefore be 3/50 = 6%.

187. All of the products are formed from the quenching of various carbocations,therefore all should have -OH groups. In the infrared spectrum, bands

characteristic of -OH groups are found near 3500 cm-1

.

188. An organism that causes human disease is isolated and studies.Researchers would conclude that the organism is a bacterium rather than a virus if

the organism reproduces in a culture medium lacking host tissue. Bacteria do not

require host tissue to reproduce, whereas viruses do.

189. The smooth endoplasmic reticulum most resembles the Golgi apparatus inan intact eukaryotic cell when viewed under the microscope. Both organellesappear to be membranes with many folds.

190. If the ratio of R to R in the product mixture is 2:1, then the startingtriglyceride must consist of two R-containing esters and one R-containing ester.


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191. Lipases catalyze the hydrolysis of fats and other carboxylic esterssimilar to fats, but not fats. Lipases ability to catalyze the hydrolysis of fats andsimilar molecules reveals that some enzymes interact with several different

substrate molecules that have similar chemical linkages.

192. In horses, the genes for red coat color and white coat color are codominant.Heterozygous horses have roan color. If a roan-colored colt (C

RC

W) has a white

mother (CW

CW

), the fathers coat must be either roan (CRC

W) or red (C

RC

R). The

mother could only give the white color gene, so the father must have given the red.

For the father to give the red color gene, he would have to carry one or two copies

of it, meaning he must be either red or roan, respectively.

193. The passage discusses the connection between H. pylori infection andincreased risk of gastric cancer. If H. pylori infection causes increased

proliferation of mucosal cells in the stomach, this could lead to gastric cancer ifgenetic mutations occur in proliferating somatic cells that line the stomach.

194. According to the passage, stomach ulcers and some forms of gastriccancer may be linked to H. pylori infections in the stomach. Without treatment byantibiotics, such infections can be persistent. The most plausible explanation for

why host antibodies are ineffective against H. pylori is that antibody proteins may

be denatured (destroyed) in the harsh (acidic) environment of the stomach. If theantibody proteins are denatured, they will not function properly.

195. According to the passage, there is more than one strain of H. pylori. Onestrain expresses the gene vacA that encodes a toxin. The other strain encodes agene cagA that leads to inflammation and might be related to the genesis of

gastric cancer. Thus, a significant difference between the strains is that the strains

express different genes.

196. According to the passage, expression of the cagA gene leads toinflammation of the mucosal lining of the stomach. Thus, the cagA gene producttriggers the movement of leukocytes into the mucosal tissuebecause leucocytes

gravitate toward an inflammation.

197. According to the passage, infection by H. pylori increases ones risk ofgastric cancer, but less than 25% of people affected ultimately develop suchcancer. Most people affected with H pylori do not develop cancer because they

tolerate the infection without developing tumors. The DNA is not damaged and

uncontrolled cell division does not occur.


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198. According to the passage, infection by H. pylori increases ones risk ofgastric cancer, but less than 25% of people affected ultimately develop such

cancer. To be most effective, a gene therapy for gastric cancer should be directed

against epithelial cells that give rise to tumors. The infection originates in theepithelial tissue, which is the same location of the cancersand the first place to

focus preventative measures.

199. Enzymatic activity in the stomach initiates the digestion of proteins.Pepsin is the enzyme, secreted into the stomach, that catalyzes the hydrolysis of

proteins into peptides and amino acids. Pepsin works most efficiently at the low

pH of the stomacha pH that is obtained by secretion of HCl.200. According to the passage, the AB cell from the two-cell stage of the

nematode, when kept in contact with the P1 cell, goes on to produce neurons, skin,

and muscle. In Experiment 1, researchers investigated the role of cell-to-cellcommunication by separating the cells of a two-cell embryo (AB and P1), and

culturing them independently. The cultured AB cells produced neurons and skin,but no muscle, whereas the cultured P1 cells gave rise to all of the tissues

produced by P1 cells of an intact embryo. The observation that the fate of anisolated AB cell is different from that of an AB cell in an intact embryo supports

the hypothesis that cell-to-cell communication is involved in the determination of

cell fate.201. In Experiment 1, researchers investigated the role of cell-to-cell

communication by separating the cells of a two-cell embryo (AB and P1), and

culturing them independently. The cultured AB cells produced neurons and skin,but no muscle, whereas the cultured P1 cells gave rise to all of the tissues

produced by P1 cells of an intact embryo. The results of Experiment 1 indicatethat the direction of signaling between the blastomeres of a two-cell embryo is P1

AB (since ABs fate differed when isolated from P1, while P1s fate was the

same regardless of whether AB was present or not).

202. In Experiment 2, two-cell embryos were incubated in either cycloheximide(an inhibitor of translation) or actinomycin D (an inhibitor of transcription). TheAB cells were then isolated and washed to remove inhibitors, and grown in

culture. AB cells of embryos treated with cycloheximide (the translation inhibitor,

which would have prevented production of proteins at the ribosomes of both ABand P1 cells) produced only neurons and skin, while AB cells of embryos treated

with actinomycin D (the transcription inhibitor, which would have prevented

production of mRNA) produced neurons, skin and muscletheir normal fate.These results indicate that the signaling interaction (between P1 and AB cells) at

the two-cell stage probably involves protein, since proteins of the P1 cells could

not have been produced to carry the necessary message(s) to the AB cells prior toisolation.


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203. The results of Experiment 3 support the conclusion that gut specificationduring the four-cell stage requires cell-to-cell communication between P2 and

EMS. As indicated in Figure 2, the only case in which gut differentiation resulted,

regardless of how long the cells were left in the four-cell stage, was thecombination of EMS and P2 cells. EMS and P2 cells that had zero minutes

incubation in the four-cell stage still resulted in gut differentiation.

204. If the zygote contains all unique cell contents that are necessary for gutdifferentiation, segregation of these substances during cell division would occurin the sequence of zygote to P1 to EMS to E. This information comes directly

from the flow chart in Figure 1, which shows that gut cells are derived from the

following source: zygote P1 EMS E.

205. According to the information provided, the only somatic or visceral cell-type tissue that derives from a single blastomere is gut. This result is shown inFigure 2, which indicates that after 10 minutes in the four-cell stage, an isolated

EMS cell can lead to gut differentiation. In addition to this, the only cases in

which gut differentiation occurred were cases in which EMS cells were present.

206. The experiments indicate that nematode cells adopt different fates fromthose of their neighbors during development by both cell-to-cell signaling and

segregation of cytoplasmic contents during cell division. The importance of cell-to-cell signaling is supported by the results of Experiment 1, in which the fate of

an AB cell depended on whether it was cultured in the presence of P1 or not. The

importance of segregation of cytoplasmic contents during cell division issupported by the results of Experiment 3, in gut differentiation only occurred in

cases where an EMS cell was present.

207. The passage shows that Compound 1 undergoes a rearrangement to form aketone and the double bond in the side chain is retained. If the compound shown

in the stem reacts in the same way an aldehyde would form and the double bondin the chain would be retained.

208. A negative entropy of activation indicates that the order of the transitionstate is increasing. This is true of Chemist 1s mechanism because the moleculewould have to achieve the correct conformation for the reaction to take place.

209. The rearrangement shown proceeding by Chemist 1s mechanism can giveonly one product. If Chemist 2s reaction mechanism were correct there couldpossibly be cross products.


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210. The -OH stretching band appears in the IR at approximately 3500 cm -1.

211. Based on the pedigree shown, the most likely pattern of inheritance forthis rare disease (expressed in fewer than 1 in 100,000 people) is sex-linked

recessive. The trait must be recessive since it does not appear in the parentsgeneration (the parents are normal), but does appear in several of the children.

The trait is most likely sex-linked because only sons are affected, and not just

sons from ONE cross, but sons from two crosses. The mother had children withtwo men, and in both cases half of her sons had the disease. The mother carries

the trait XAX

a, and passes the trait to half of her sons who inherit a Y from their

father, thus leaving them with the disease (Xay). Daughters cannot inherit the

disease because the father always gives a normal chromosome (XA). Half the

daughters will be entirely unaffected, and half are expected to be carriers like their

mother.

212. The gall bladder stores bile produced by the liver and secretes it into thesmall intestine as needed. Bile acts as an emulsifier, facilitating fat digestion.

When the gall bladder is removed, a patient will have reduced ability to digest fats.

213. Unlike other organisms, the liver can partially regenerate after illness ordamage. This regeneration is accomplished by mitosis. Mitosis is the processwhereby human body cells (not gametes) reproduce.

214. The N-H bond in Compound I would be capable of forming hydrogenbonds with water making it more soluble that the non-polar Compound II.

215. In humans, cholesterol is a precursor to testosterone. Cholesterol andtestosterone are only two of several steroid-based natural molecules. The bodymakes uses of the steroid backbone of cholesterol to produce the hormone

testosterone.

216. This item includes a description of an experiment in which actively-dividing, synchronized cells were exposed to radioactively labeled 2-deoxythymidine (the nitrogen base incorporated into DNA, but not RNA). After

30 minutes of exposure to the radioactively labeled substance, the cells were

rinsed to remove unabsorbed label. At various times thereafter, a group of cellsfrom the culture were examined to determine the quantity of radioactive material

in the nuclei. The figure shows a peak in radioactivity between 3 and 13 hours


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after treatment. This peak represents DNA synthesis, since 2-deoxythymidine is a

component of DNA, but not RNA or protein

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