MCAT Practice 1 Test Q&A

The LXCXE motif is described as being "highly conserved." Certain parts of the genome, such as that encoding the LXCXE motif, are highly conserved because they are: A. vital to an organism's survival. B. chemically incapable of mutation. C. stored in vesicles for later secretion. D. stored in cell compartments where they are unlikely to be secreted.

A. From an evolutionary point of view, DNA sequences that are vital to an organism's life are conserved among species.

Which phenomenon does the passage NOT explain? A. The successful reclusive writer B. The popularity of academic conferences C. Summer programs for musicians D. Small towns where artists tend to live

A. If creativity and ideas thrive when there is human interaction (as described in paragraph 4, for instance), then it would be difficult to explain the phenomenon of a successful but reclusive writer (who had very little human interaction).

The author's use of the word "resisters" gives the impression that the author wants to: A. discuss the migrants in a nonjudgmental way. B. emphasize that the migrants opposed authority. C. portray the migrants as unpatriotic citizens. D. suggest that the migrants' reasons for going to Canada were justified.

A. "Resister" implies, in a neutral way, the migrants' motivation for leaving the U.S. The nonjudgmental tone that is created by this word choice is implied early in the passage since resister is chosen over more familiar (but also negative) terms: "Just over 100 resisters, known more commonly as 'draft dodgers' and 'deserters,' came to Canada in 1964" (first paragraph).

An increase in which of the following physiological variables is most likely to cause an increase in the amount of EPO released by the kidneys in a healthy human adult? A. Amount of aerobic exercise the person performs B. Total amount of circulating hemoglobin C. Rate of erythrocyte maturation D. Cardiac output (volume of blood pumped by the heart per minute)

A. An increase in aerobic exercise results in an increase in oxygen demand. This will cause an increase in the amount of EPO released by the kidneys.

If all else is held constant, which of the following changes would NOT double the volume of a gas? A. Doubling the pressure B. Doubling the absolute temperature C. Halving the pressure D. Doubling the number of gas molecules

A. Based on Boyle's Law, P is inversely proportional to volume, thus, doubling the pressure of a gas sample will decrease, not increase, the volume.

The association observed experimentally between the expression of miRNAs and mRNAs in AR kidney transplants indicates that miRNAs regulate the expression of genes implicated in which type(s) of immune response(s)? A. Adaptive immunity only B. Humoral immunity only C. Innate and cell-mediated immunity only D. Adaptive and innate immunity only

A. Based on Experiment 2, only the expression of T and B cell mRNAs is positively correlated with the three miRNAs analyzed (miR-142-5p, miR-155, and miR-223). T and B cells belong to the adaptive immune system: T cells regulate cell-mediated responses and B cells regulate humoral responses.

These experiments suggest that the mutant RB proteins do not: A. bind to E7. B. bind to E2F. C. arrest cells in G1. D. permit exit from G1.

A. Based on the results shown in Figure 1, addition of E7 to wild-type RB results in a decrease in the percentage of cells in G1. However, when wild-type RB is replaced by mutant RB, this decrease is not observed. This indicates that the mutants are insensitive to E7, and do not likely interact with E7.

The second purification step is which type of chromatographic separation? A. Affinity B. Size exclusion C. Cation exchange D. Anion exchange

A. Displacement of the protein from the column in this step involved disrupting the binding of the (His)6 tag to the column. This is a classic example of affinity chromatography.

Which cells express lactase? A. Enterocytes of the duodenal villi B. Epithelial cells of the colon lining C. Parietal cells of the stomach lining D. Bile-producing hepatocytes of the liver

A. Enterocytes are the intestinal cells that produce Enzymes that digest disaccharides. This includes lactase.

If the red line in the Balmer series has a wavelength of 656 nm, which of the following is closest to its frequency? A. 4.6 × 10^14 Hz B. 4.6 × 10^−​14 Hz C. 2.1 × 10^15 Hz D. 2.1 × 10^−​15 Hz

A. For light that travels in vacuum, wavelength and frequency are related according to wavelength × frequency = 3.0 × 10^8 m/s. Solving for frequency yields (3.0 × 10^8 m/s)/(656 × 10^-9 m) = 4.6 × 10^14 Hz.

Which structural change to Compound 1 would make it more water soluble? A. Replacing benzene CH with N in the ring B. Replacing C=O with C=CH2 C. Replacing N-N=N with CH-CH=CH D. Replacing NH with NCH3

A. Nitrogen in the benzene ring would have a lone pair that could accept a hydrogen bond from water, thus increasing the solubility of the compound.

Based on information presented in Table 1, which relationship between pH and charged functional groups is accurate? A. At pH 8.50, the ratio of the cationic to anionic functional groups in the NqrD subunit is equal to 1. B. At pH 7.00, half of the functional groups in the NqrE subunit are protonated. C. At pH 6.30, the net charge of the cationic and anionic functional groups in the NqrA subunit is equal to 1. D. At pH 6.00, the majority of the functional groups in the NqrF subunit are protonated.

A. Table 1 shows that the isoelectric point of NqrD is 8.50. The ratio of the cationic (+) to anionic (-) functional groups in a protein at its pI is always equal to one.

Which classification of amino acids applies to the Trp residues after photochemical modification by CCl3CO2H? A. Acidic B. Basic C. Hydrophobic D. Polar neutral

A. The Trp residues after being photochemically modified by CCl3CO2H have a carboxylic acid group attached to the benzene ring.

How does the Unit Membrane Model differ from the Fluid Mosaic Model? A. The location of proteins differs in the two models. B. The Unit Membrane Model has a monomolecular layer of protein on each surface, while the Fluid Mosaic Model has a bimolecular layer of protein on each surface. C. The Unit Membrane Model has one layer of phospholipids, while the Fluid Mosaic Model has two layers. D. The Unit Membrane Model contains dissolved protein, while the Fluid Mosaic Model is coated with a monomolecular layer of protein on each surface.

A. The Unit Membrane Model indicates that the proteins form a monomolecular layer both outside and inside the phospholipid bilayer and that the proteins do not penetrate the phospholipid layer. In the Fluid Mosaic Model, the proteins are inserted in the phospholipid bilayer.

Niche populations often do not benefit from broadly targeted approaches. What is the relevance of this statement to the passage? A. It supports the need for an alternative to the prevailing approach to improving population health. B. It explains why the kind of "long tail" thinking advocated by Anderson will be of only limited value to public health interventions. C. It suggests that the MIYO system described in the passage will not achieve its intended public health goal. D. It challenges the critique of local public health organizations with respect to funding, capacity, and infrastructure.

A. The author explains that the "prevailing approach to improving population health emphasizes 'shifting the mean' through prevention efforts that target large groups at high risk for particular conditions, or through mass interventions . . . " (first paragraph). If "niche" populations or subgroups often do not benefit from such broadly targeted approaches, that clearly supports the need for another approach to improving population health, which is what the passage describes.

One can infer from the passage that the author considers nature NOT to be: A. carefully arranged. B. aesthetically pleasing. C. ecologically complex. D. infinitely mutable.

A. The author's contention that nature is NOT "perfect" or enormously tidy supports this option: "...one cannot resist the feeling that each of these works is as carefully arranged, composed, and synthetically created as the gardens Monet cultivated at his home in Giverny. The overall compositions are often very simple, yet they seem carefully selected and perfectly balanced—too perfect to be an accident of nature" (paragraph 4).

Which of the following assertions, if true, would most weaken the author's point about the nature of the American migration to Canada from 1965 to 1973? A. Of the 20 percent of immigrants to Canada that came from the U.S., only a very small proportion had political motivations for their move. B. The number of immigrants was actually closer to 50,000 than to 100,000. C. More than 50 percent of the immigrants returned to the U.S. in the decade after the Vietnam War. D. In the period after the Vietnam War, migration from the U.S. to Canada decreased noticeably.

A. The author's point in the passage is to show the large influence that the Vietnam War had on American migration to Canada, which the author characterizes as "the largest politically motivated migration from the United States since the Loyalists moved north to oppose the American Revolution" (first paragraph). If most migration of Americans to Canada during these years was not politically motivated, this information would weaken the author's point about the nature of American migration to Canada in the period.

If the defibrillator described in the passage were fully charged and the entire charge were discharged through a patient in 10 ms, which of the following is closest to the average electrical current that would flow through the paddles? A. 7.5 A B. 15 A C. 22.5 A D. 30 A

A. The full charge of the capacitor is 25 μF × 3000 V = 75 mC. The average discharge current is (75 mC)/(10 ms) = 7.5 A.

Which outcome most likely results from exposure of Ogg1-/- mice to TNFα A. Increase in cancer incidence B. Increase in Cxcl2 expression C. Decrease in cellular ROS levels D. Decrease in KD of TH5487 for its target

A. The passage notes that exposure to pro-inflammatory agents such as TNFα leads to cellular production of ROS, which leads to generation of 8-oxo-G. The passage notes that this altered version of G is capable of forming Hoogsteen base pairs with A, leading to mutations within the DNA. Knockout mice would not have OGG1 available to repair the damaged DNA. Long-term lack of genetic stability would increase the incidence of cancer.

Two open flasks I and II contain different volumes of the same liquid. Suppose that the pressure is measured at a point 10 cm below the surface of the liquid in each container. How will the pressures compare? A. The pressures will be equal. B. Pressure in flask I will be less. C. Pressure in flask II will be less. D. The pressures cannot be compared from the information given.

A. The pressure at a point 10 cm below the surface of the liquid is the same in both flasks because the pressure is equal to the liquid density multiplied by the gravitational acceleration multiplied by 10 cm.

If both the capacitor and the power supply in Figure 1 are adjustable, which of the following changes would result in an increase in the charge on the capacitor? A. Decreasing the area of the parallel plates B. Decreasing the separation between the parallel plates C. Removing the dielectric from the capacitor D. Decreasing the voltage of the power supply

B. Capacitance C is inversely proportional to the separation d between the parallel plates according to the formula C =(ϵ0 ϵr A)/d. A decrease in the separation corresponds to an increase in the capacitance. Given that the charge on the capacitor is directly proportional to the capacitance, an increased capacitance results in an increase in the charge as long as the power supply voltage is constant.

What is the identity of an atom that contains six protons and eight neutrons? A. Nitrogen B. Carbon C. Oxygen D. Silicon

B. Carbon contains six protons because it also contains six electrons as a neutral atom.

The poem "Kubla Khan," written by influential nineteenth-century poet Samuel Taylor Coleridge, contains images he derived from ancient Chinese history as well as images he had seen in a dream. How would this example affect the ideas in the passage? A. It would support the passage author's point that the romantic poets looked to other countries and the imagination for inspiration. B. It would support the passage author's point that the romantic poets were maladjusted and antisocial. C. It would challenge the passage author's point that the romantic poets primarily focused on the natural landscapes of England. D. It would challenge the passage author's point that the romantic poets primarily focused on the revolutionary issues of their own era.

A. The prompt clearly supports the author's discussion about the inspirations of the romantic poets. The statement about Coleridge's reliance on images from ancient Chinese history supports the passage claim that the romantic poets often looked "outward to remote and fascinating nations or centuries" (paragraph 3) for inspiration. The reference to the poem coming in part from a dream supports the author's contention that the poets valued both "individualism" and the "creative imagination" (paragraph 3).

Based on the reported Hill coefficient, in what way do the MCS oligomers affect inhibition? A. As one MCS oligomer binds to the ATPase, it makes it easier for the others to bind, leading to inhibition. B. As one MCS oligomer binds to the ATPase, it makes it more difficult for the others to bind, leading to inhibition. C. A single MCS oligomer binds to the ATPase, leading to inhibition. D. MCS oligomers randomly bind to the ATPase, leading to inhibition.

A. The reported Hill coefficient of 2.56 indicates positive cooperativity because the value is greater than 1.0. Therefore, when one MCS oligomer binds to the ATPase, it makes it easier for others to bind. When there are sufficient MCS oligomers bound, they lead to inhibition of the ATPase.

Which type of heterocycle is found on two amino acid residues blocking access to W15? A. Imidazole B. Indole C. Pyrimidine D. Pyrrole

A. The two amino acid residues blocking access to W15 are histidines, each with an imidazole ring-containing side chain.

An ester is prepared by the method of direct esterification using an esterase enzyme as a catalyst. Which of the following modifications will NOT appreciably increase the final yield of ester? A. Using 2 times as much enzyme B. Using 2 moles of RCOOH instead of 1 mole C. Using 2 moles of RCH2OH instead of 1 mole D. Removing RCOOCH2R from the reaction mixture as it is formed

A. This modification will increase the rate of formation, not the final yield of ester.

A 2 kg mass and a 5 kg mass are connected by a massless cord suspended over a massless and frictionless pulley. If the acceleration due to gravity is g, what will be the acceleration of the masses after they are released from rest? A. 2g/7 B. 3g/7 C. 5g/7 D. g

B. According to Newton's second law, the net force acting on the 5-kg mass is given by the expression Fnet= 5 kg × a1 = 5 kg × g - T, where a1 is the acceleration after the release and T is the tension in the cord. The net force acting on the 2-kg mass is given by the expression Fnet= 2 kg × a2 = 2 kg × g - T. Because the two masses move simultaneously but in opposite directions after they are released, a1 = -a2 = a. Substituting the expression T = 5 kg × (g - a) into the equation of motion of the 2-kg mass yields -2 kg × a = 2 kg × g - 5 kg × (g - a) = -3 kg × g + 5 kg × a. Then 7 kg × a = 3 kg × g, hence a = 3g/7.

The information in the passage best supports which hypothesis? A. Exercise prevents glucose uptake. B. Exercise promotes less effective cellular respiration. C. Exocrine secretions of skeletal muscle act on adipose tissue. D. Endocrine secretions of adipose tissue act on skeletal muscle.

B. According to the pathway suggested by the information in the passage, exercise ultimately increases UCP1 levels which in turn degrades the proton gradient that drives oxidative phosphorylation. More energy is dissipated as heat and less is used to synthesize ATP.

Assume that a certain dominant mutation in the EPO gene exists such that a person who carries this mutant EPO allele has a higher-than-normal number of circulating erythrocytes. Which of the following best describes a mechanism by which this mutation could have its effect? A. The promoter of the mutant EPO allele is defective, and the allele is not transcribed. B. The mutant EPO allele produces a protein that has an increased affinity for EPOR. C. The mRNA produced by the mutant EPO allele is degraded before translation can occur. D. The mutant EPO allele produces a protein that is unable to bind EPOR.

B. An increased affinity of EPO for EPOR will enhance EPOR activity, stimulating erythrocyte production.

Based on the passage, where do the views of Sarris and Buscombe most likely converge? A. Sarris's evaluative criteria are consistent with Buscombe's first recommendation. B. Sarris's discussion of interior meaning is consistent with Buscombe's second recommendation. C. Sarris's argument about foreign films and documentaries conflicts with Buscombe's third recommendation. D. Sarris's overall approach to American directors supports Buscombe's overall approach to film criticism.

B. Buscombe's second recommendation is that critics should study "the effects of society (including ideology, economics, and technology) on cinema" (final paragraph). This is in accord with the passage representation of Sarris's view of interior meaning, "which, Sarris maintained, arose from the tension between the director and the conditions of production within which the director worked (the system of film studios in Hollywood, CA)"

In μM•s-1 and μM, what should the approximate values of kcat/KM and Ki be, respectively, when [I] = 180 μM? A. 33.5 and 15.7 B. 75 and 30.1 C. 150 and 60.3 D. 300 and 120.6

C. Based on the data in Table 1, increasing [I] has no effect on kcat/KM, so it should remain at 150 μM•s-1. Also, Ki is an equilibrium constant, so it will not be affected by a change in [I].

Which is a plausible reason why participants with the attachment style investigated are less likely to seek support from others in times of stress? A. Participants think that others are reluctant to get close to them. B. Participants find it difficult to trust and depend on others. C. Participants do not worry that they will be abandoned by others. D. Participants want to merge completely with others and this desire pushes people away.

B. Difficulties in trusting and depending on others is one of the primary characteristics of an avoidant attachment style, and is a plausible explanation for why avoidantly attached individuals are less likely to seek support from others in times of stress.

Which comparison best determines whether IFNγ is necessary for antidepressant-induced increases in the expression of p11? Expression levels of p11 in: A. wild-type mice versus IFNγ knockout mice, both treated with p11 B. wild-type mice versus IFNγ knockout mice, both treated with an SSRI C. wild-type mice treated with IFNγ versus wild-type mice treated with an SSRI D. wild-type mice treated with IFNγ versus wild-type mice treated with ibuprofen

B. In order to study antidepressant-induced increases in p11 expression, both test groups must be given an antidepressant, or SSRI. To study the additional effect of IFNγ, one test group should be non-affected (wild-type) and the other should lack IFNγ (IFNγ knockout).

What is the most likely effect of adding a sodium ionophore to a culture of V. cholerae? A. Decreased activity of Na+-NQR B. Decreased production of ATP C. Decreased pH of the periplasm D. Decreased consumption of O2

B. Ionophores are compounds that bind to ions and facilitate their movements across membranes. A sodium ionophore would collapse the sodium gradient (sodium motive force) that is established by the action of Na+-NQR, resulting in decreased production of ATP.

Expression of the rHuEPO gene in E. coli bacteria produced an EPO protein that did not increase erythrocyte production when injected into humans. The most likely reason for this observation is that: A. prokaryotic ribosomes interpret the genetic code in a completely different manner than do eukaryotic ribosomes. B. E. coli cannot glycosylate EPO in the same way that it is glycosylated by eukaryotic cells. C. bacteria are unable to secrete eukaryotic proteins. D. only viruses contain the necessary cellular machinery to properly express recombinant proteins.

B. Lack of EPO function could be caused by a failure of EPO to activate EPOR. Glycosylation is a process that is crucial for the structural conformation of the protein, in which structure is a main determinant of whether a particular ligand activates a receptor. Thus, differences in protein glycosylation could prevent EPO from properly activating EPOR.

Based on the passage, what does Robert Lucas most likely mean by the "usual economic forces" (paragraph 3)? A. The tendency of businesses to locate near their competitors B. The tendency to consider expense as a primary driver of choice C. The factors that lead cost of living to be high in many urban areas D. The preference people show for the newest and most valuable items

B. Lucas says that the "usual economic forces" would suggest that people should not be drawn to cities. The author goes on immediately to ask, "why would young designers live in New York when they could live more comfortably in other cities with much lower costs of living?" The implication is that this question describes the usual economic forces at work, which, in this case, would be the forces that prioritize the tangible items or circumstances (leading to comfort) that one can get for one's money.

The gene for red-green color blindness is recessive and X-linked. What will be the expected phenotype of the children of a color-blind woman and a man who is not color-blind? A. All of the children will have normal color vision. B. All of the daughters will have normal color vision; all the sons will be color-blind. C. All of the sons will have normal color vision; all the daughters will be color-blind. D. Half of the daughters will have normal color vision, and half of the daughters will be color-blind; all the sons will be color-blind.

B. Males are XY and females are XX. All sons will inherit the X chromosome carrying the color-blind mutation from their mother along with a Y chromosome from their father, and will be color-blind. Daughters, however, will inherit one color-blind X chromosome from their mother and the wild-type X chromosome from their father. As the mutation is inherited in a recessive manner, daughters will have normal color vision, but will be carriers of the mutation.

The resting potential of a neuron is primarily a result of the: A. release of neurotransmitters from the axon. B. distribution of ions across the plasma cell membrane. C. action of neurotransmitters on the postsynaptic receptor. D. active transport of Ca2+ ions across the plasma cell membrane.

B. Membrane potential refers to the difference in charge distribution on opposing sides of a cell membrane. Within a neuron, the resting potential is determined by the normal, uneven distribution of ions between the outside and the inside of a cell.

Which of the following is a weakness in the Unit Membrane Model? A. The Unit Membrane Model does not define the cell's size. B. The Unit Membrane Model does not suggest how the exchange of nutrients and wastes occurs. C. The Unit Membrane Model does not act as a barrier between the contents of the cell and the cell's external environment. D. The hydrocarbon bilayer allows passage of polar molecules through the membrane.

B. Nutrients and wastes are often exchanged by crossing the cell membrane. The Fluid Mosaic Model describes transmembrane proteins that can mediate such exchange. However, the Unit Membrane Model does not provide a mechanism for how the passage of nutrients and wastes occurs.

If the combined mass of the TPMT substrate and cofactor was determined before the enzymatically catalyzed reaction and then compared to the combined mass of the product and the cofactor after the reaction, the net change in molecular weight will be: A. +15 g/mol. B. 0 g/mol. C. -15 g/mol. D. -16 g/mol.

B. TPMT is a transferase. It is transferring the methyl group from the cofactor to the substrate. Hence, the total net change in mass would be 0 g/mol.

The structure of Compound 2 is shown. What structural feature(s) is(are) most important to the functioning of this compound as described in the passage? A. Specific configuration of numerous chirality centers B. Multiple hydrolysable linkages C. Combination of large hydrophobic and hydrophilic regions D. Presence of a reducing sugar

C. Compound 2 was used as a detergent. It liberated a protein from a membrane so that it might be isolated. The combination of large hydrophilic and hydrophobic regions allows Compound 2 to function in this capacity.

Of the following novels from the romantic era, which best exemplifies the theories about them presented in the passage? A. A novel that examines the inner life of an orphaned girl who becomes a governess in an isolated Gothic manor B. A novel that examines the detrimental effects of chancery, the system during this time for distributing money from a will C. A novel that follows the exploits of a medieval knight facing various challenges, including issues of prejudice D. A novel that examines the devastating effects of repressed knowledge

B. The author argues that novelists worked "to symbolize, to comprehend, and to interpret in terms of value the increasing complexities of modern society . . ." (paragraph 2). This example of a novel, which explores the economic effects of a real-world legal system, describes a novel doing what the author argues nineteenth-century novelists did: grappling with the realities of an increasingly complex modern world.

According to the author's account, the experience of working on an engineering project is LEAST like that of: A. a chef in imagining the menu for a dinner. B. a reporter in gathering facts for an article. C. a travel agent in creating a vacation package. D. an artist in making sketches for a mural.

B. The author represents scientists (in contrast to engineers) as most like reporters gathering facts.

Communications scholar Bernard Armada writes that museums can "only cue us into segments of history — they can never represent 'the' past in all of its social, cultural, and political complexity". How would the passage author most likely respond to this claim? A. The author would disagree, citing the accuracy of the representations in the Delta Blues Museum. B. The author would say that this claim does not negate passage arguments about the Delta Blues Museum. C. The author would suggest that the past is likely more accessible and unidirectional than this quotation implies. D. The author would suggest that this point undermines the passage discussion of the Delta Blues Museum.

B. The author would likely suggest that even if museums cannot be perfectly comprehensive, they can do more than create exhibits that adhere to certain images of authenticity and leave out certain narratives. Further, the claim in the question points precisely to the more complex reality of the blues that the author seeks to illuminate.

Why does the author most likely mention migrant farmworkers (paragraph 4)? A. To give an example of the kind of population group that might be difficult to reach with a long tail approach B. To give an example of the range of health statuses and circumstances that might require targeted resources C. To provide support for the argument that broader health initiatives have an important place in public health D. To provide support for the argument that a long tail approach has not been tried in circumstances where it might be most useful

B. The author writes: "the number and complexity of niche markets increase exponentially when we consider how certain illnesses and preventive services affect different population subgroups, with different constellations of demographic, geographic, and health status risk factors. Approaches might be targeted to groups as diverse as migrant farmworkers in rural communities, parents of children with asthma . . . " (paragraph 4). Migrant farmworkers, then, provide an example of a "niche market," or "population subgroup" with particular health circumstances that could require the kind of specific, targeted resources that the author describes.

In which phase(s) will the MCS precursor be predominantly found after the extraction step? The MCS precursor will: A. be found in the aqueous layer. B. be found in the tert-butyl methyl ether layer. C. be distributed equally between the aqueous layer and the tert-butyl methyl ether layer. D. form a precipitate between the aqueous and tert-butyl methyl ether layers.

B. The passage described the MCS precursor as being lipophilic, which means that it would not dissolve as readily in the aqueous layer. Therefore, it should be found in the tert-butyl methyl ether layer, which is hydrophobic.

Which reactant and product (one equivalent each) are necessary to balance Reaction 1? A. Reactant = H2O, product = NO3_ B. Reactant = H2O, product = NH4+ C. Reactant = O2, product = NO3_ D. Reactant = O2, product = NH4+

B. The reactant loses an ammonium ion and gains a water molecule. This balances both charge and mass on both sides of the chemical equation.

A person pushes on a rolling cart with a force that diminishes with time because the person must walk faster to keep up with the accelerating cart. How much work does the person generate while pushing on the cart? A. 500 J B. 1000 J C. 2000 J D. 4000 J

B. The work generated by the person while pushing the cart is equal to the area under the force-distance line, according to the definition of work. The area is equal to 1/2 × (100 N - 0 N) × (20 m - 0 m) = (100 N × 20 m)/2 = 1000 J.

What is the molecular formula of the heterocyclic aromatic compound pyrrole? A. C2H3N B. C4H5N C. C6H7N D. C8H9N

B. This is the molecular formula of pyrrole, a five-membered aromatic heterocycle containing one nitrogen atom.

Which of the following is closest to the wavelength of a photon whose energy is 2 eV? A. 740 nm B. 620 nm C. 450 nm D. 310 nm

B. Using hc = 4.1 × 10-15 eV•s × 3 × 108 m/s = 1230 eV•nm, and λ = hc/E, then E = 2 eV corresponds to λ = (1230 eV•nm)/(2 eV) = 615 nm, which is closest to 620 nm.

Which of the following observations would invalidate the Unit Membrane Model? A. When a thin section of membrane is observed using a microscope at high magnification, two layers of phospholipid heads are observed. B. Thermodynamic measurements indicate that the phospholipid heads are exposed to water. C. When a membrane is frozen and then split from surface to surface, proteins are observed within the hydrocarbon chains. D. Thermodynamic measurements indicate that the phospholipid tails are hidden inside the membrane, away from exposure to water.

C. According to the Unit Membrane Model, the proteins form a monolayer on the outer and inner surfaces of the phospholipid bilayer. Thus, when this bilayer is split, there should not be proteins observed within hydrocarbon chains. Instead, the proteins should be equally separated by the split.

Based on Figure 1, which patient is LEAST likely to benefit from therapy with immunosuppressors? A patient whose transplanted kidneys are associated with miRNA expression patterns characterized by: A. high levels of miR-155 B. low levels of let-7c. C. high levels of miR-30a-3p. D. low levels of miR-10b.

C. Based on Figure 1, high levels of miR-30a-3p are associated with normal transplant. These data suggest that such individuals would not benefit from the treatment with immunosuppressors.

The author implies that the examples of both Robert Cray and B.B. King (paragraph 3) have what kind of relationship to the more traditional images of blues musicians? A. Redundant B. Irrelevant C. Inconsistent D. Exaggerated

C. Cray and King are described in the passage as "having amassed considerable fortunes" (paragraph 4), whereas the more traditional image of the blues musician (the one the passage suggests is seen as "authentic," is of "struggling artists with limited means" (first paragraph). So the depictions of Cray and King are inconsistent with that dominant image.

Enantiomers can exhibit a difference in which chemical or physical property? A. Density B. Boiling point C. Smell D. IR spectrum

C. Enantiomers have the same physical and chemical properties. They differ only in their three dimensional arrangement of atoms and their interactions with other chiral molecules. They can differ in their smell due to interacting differently with chiral odorant receptors.

Which statement is LEAST relevant to the passage as a whole? A. Health messages can be thought of as products. B. Health messages can be targeted to specific population subgroups. C. Specific population subgroups may be receptive to "blockbuster" messages. D. Specific population subgroups may have unequal access to beneficial resources.

C. Even if specific population subgroups may be receptive to so-called "blockbuster" messaging, which targets "large groups" (first paragraph), this is not particularly relevant to the passage as a whole, which emphasizes the value of providing specific, focused public health messaging to population subgroups in general. That some particular subgroups may respond to blockbuster messaging is not particularly relevant to this argument.

Historically, some literary critics have routinely disparaged certain popular genres, such as mystery, thriller, or romance novels. Assuming this to be true, how does it relate to passage claims? A. It supports Astruc's approach to the role that literature should play in relation to film. B. It calls into question the evaluative criteria developed by Sarris. C. It suggests that the attitude opposed by Sarris is not confined to film critics. D. It suggests that advocates of the auteur theory may have misjudged the typical tendencies of critics.

C. In paragraphs 4 and 5, the author writes, "Yet to make the case that popular culture and mass-produced art was worthy of critical discussion was no easy matter. Sarris sought to bring critical analysis to Hollywood cinema against a background of critical condescension." This scenario described in the prompt (deprecation of popular literature), then, suggests that the attitude Sarris resisted was hardly confined to film critics.

Certain types of kidney tumors continuously produce and release EPO. Such tumors most likely have which of the following effects, if any, on erythrocyte production? A. The liver will take over the process of regulating erythrocyte production. B. Erythrocyte production within the bone marrow will cease. C. Constant stimulation of erythrocyte production will occur within the bone marrow. D. There is no effect; erythrocyte production will continue to be regulated by the kidneys based on oxygen levels within the body.

C. Increased levels of circulating EPO will result in increased bone marrow stimulation to produce more erythrocytes.

If only [I] is increased, then [ESI] or [EI] increases. This is an example of: A. the Bose-Einstein Principle. B. the Heisenberg Uncertainty Principle. C. the Le Châtelier's Principle. D. the Pauli Exclusion Principle.

C. Le Châtelier's Principle states that in a reversible process, the application of stress to the system will cause the system to respond in a way that will relieve this stress. In this case, the reversible process is E + I forming EI or ES + I forming ESI. In either case, increasing [I] induces stress of the system, and the system relieves that stress by converting I to either more EI or ESI.

When the covalent attachment to alliinase is broken, PLP is still held rigidly in the active site by a salt bridge and a π-stacking interaction. These interactions are most likely provided by the side chains of which amino acids? (Note: The salt bridging amino acid is listed first.) A. Asp and Tyr B. Glu and Ser C. Arg and Tyr D. Lys and Ser

C. PLP has a negatively charged phosphate that can make a salt bridge with the positively charged side chain of Arg, and the aromatic ring in the side chain of Tyr can form a π-stacking interaction.

What is the number of neutrons in the nucleus of the atom used to produce laser radiations? A. 48 B. 49 C. 50 D. 51

C. The 8636Kr atom contains 36 electrons and 36 protons. Therefore, the number of protons is equal to 86 - 36 = 50 neutrons.

Which membrane transporter is electrogenic and translocates a net charge across the membrane? A. Na+− H+ exchanger B. Na+−Cl- cotransporter C. Na+−glucose cotransporter D. GLUT2 facilitative glucose transporter

C. The Na+-glucose cotransporter transports Na+ cations and glucose into the cell. This process is electrogenic, as it results in the net movement of positively charged molecules into the cell.

If the energy of a photon is doubled, which of the following properties of the photon will also double? A. Amplitude B. Wavelength C. Frequency D. Intensity

C. The energy of a photon is given by the relationship E = hf. If E is doubled, then frequency f is doubled, too, as Planck's constant h does not change.

Based on the information in the passage, the mutation that causes the LP phenotype is most likely located in: A. an intron within the lactase gene. B. the coding sequence of the lactase gene. C. an enhancer sequence of the lactase gene. D. the stop codon at the end of the lactase gene.

C. The enhancer is a DNA region that is able to bind transcriptional activators in order to increase the expression of a particular gene. Since LP is caused by continuous lactase synthesis, this is the region most likely targeted by the mutation. Specifically, the mutation makes it easier for transcriptional activators to bind an enhancer sequence.

Based on data shown in Figure 2, what are the effects of OGG1 and TH5487 on Cxcl1 expression? I. OGG1 reduces the TNFα induced Cxcl1 expression. II. OGG1 stimulates the TNFα induced Cxcl1 expression. III. TH5487 reduces the OGG1-mediated Cxcl1 expression. IV. TH5487 stimulates the OGG1-mediated Cxcl1 expression. A. I and III only B. I and IV only C. II and III only D. II and IV only

C. The figure shows that in wild-type cells exposed to TNFα, the OGG1-deficient cells exhibit reduced Cxcl1 expression levels, indicating that OGG1 stimulates the TNFα-induced Cxcl1 expression. Furthermore, the figure shows that compared to untreated wild-type cells, TH5487-treated wild-type cells exhibit reduced OGG1-mediated Cxcl1 expression, inferring that TH5487 inhibits the OGG1-mediated Cxcl1 expression.

Which experimental evidence suggests that the purified hMPRα obtained by the researchers was in its native state? The hMPRα that was obtained: A. retained both the Compound 1 and (His)6 tags. B. was purified by two separate chromatography steps. C. exhibited a binding affinity for progesterone that was similar to that exhibited by native hMPRα. D. had a nearly identical molecular weight to hMPRα obtained elsewhere.

C. The only way to tell for certain that a protein is still in its native state is to compare its functioning to the levels observed for protein believed to be in the native state. The researchers compared the binding affinity of progesterone of hMPRα both before (when it is assumed to be in its native state) and after releasing it from the membranes (which could conceivably cause denaturation). The fact that the affinities were the same suggests that the isolated hMPRα is indeed in the native state.

Based on the passage, which statement is most likely to be true of luftmenschen? A. They tend to value innovation but do not necessarily have innovative ideas. B. They are more likely to be interested in the present than in the future. C. They are likely to be less pragmatic than theoretical. D. They are rarely found outside of urban environments.

C. The passage describes the luftmenschen as those who "lived on air" (first paragraph) and then contrasts the presence of people like this with the reality that "there comes a point when something tangible must be made." These two things together suggest that the luftmenschen are less practical than theoretical.

Researchers measured the NF- κB occupancy of the Cxcl2 promoter following exposure to TNFα both in the presence and absence of TH5487. Based on the data presented in the passage, which figure depicts the expected results?

C. The passage notes that cells increase ROS production in the presence of pro-inflammatory signals such as TNFα and that this leads to generation of 8-oxo-G. OGG1 binding of 8-oxo-G within the promoter drives NF-κB recruitment to the promoter. This means that NF-κB occupancy of the promoter should increase when the cell is exposed to TNFα.

The passage author most strongly implies which of the following ideas about the novel? A. The novel shared with poetry much of its romantic ideals. B. Novels were written by authors who could not handle the real world. C. The novel was not a major literary form before the nineteenth century. D. Novels were written by people who were primarily interested in acquiring financial power.

C. This option is supported by the author's characterization of the novel: "In the novel, which during the nineteenth century assumed major importance as a literary form. . . " (paragraph 2). If the novel "assumed major importance" in the nineteenth century, the author then implies that it was not a "major literary form" before then.

Which statement, if assumed to be true, most challenges the author's claim regarding reproductions of Monet's art? A. Many reproductions of Monet's art are indistinguishable from the originals to the casual viewer. B. Reproductions of paintings are not necessarily photographic reproductions. C. A good reproduction can heighten detail. D. Many reproductions of Monet's art sell for very high prices.

C."It is because this work lives in such details that the paintings' deepest beauty does not survive in reproductions" (paragraph 3) suggests that reproductions lack detail, which makes this option correct as it challenges this implication.

What is the name of the ionic compound used to make Buffer B? A. Ammonium formate B. Ammonium carbonate C. Ammonium bicarbonate D. Ammonium acetate

D. Ammonium acetate is NH4CH3CO2, a component of Buffer B.

Samples from various time points of the proteolysis of TPMTwt were subjected to SDS-PAGE under reducing conditions. Which figure best depicts the expected appearance of the gel? (Note: The arrow indicates the movement of the protein through the gel.)

D. As befits proteolysis, the number of lower molecular weight bands with time increases and the original protein band at the highest molecular weight diminishes with time.

Based on the passage, the microbiome of CD-affected individuals will result in which physiological change? A. Increased polypeptide digestion B. Slower dietary fiber absorption C. Increased amount of propionate D. Decreased immune tolerance

D. As explained in the passage, molecules such as butyrate, acetate, and propionate inhibit the inflammatory response against commensal bacteria of the GI tract. CD is an inflammatory condition, in which Table 1 indicates that many bacteria producing these anti-inflammatory molecules are reduced during CD. This is consistent with the interpretation that inflammation observed during CD is caused by decreased production of propionate, butyrate, and acetate, which decreases immune tolerance of commensal bacteria.

As infants, what type of parent-infant interaction most likely occurred for the participants? A. A confused infant-parent bond that is characterized by mixed separation anxiety and a tendency for the infant to resist and have a dazed behavior B. An infant-parent bond that is characterized by some separation anxiety and a tendency for the infant to seek contact with the parent after separation C. An infant-parent bond that is characterized by strong separation anxiety and a tendency for the infant to resist contact with the parent after separation D. An insecure infant-parent bond that is characterized by little separation anxiety and a tendency for the infant to resist contact with the parent

D. Avoidant attachment is associated with little separation anxiety and a tendency to resist contact with the parent, as described in the option.

Based on Reaction 1, when 1.0 atm of CO(g) completely reacts to form carbon suboxide at 550°C in a sealed container, what is the final pressure in the container? A. 0.00 atm B. 0.10 atm C. 0.25 atm D. 0.50 atm

D. Based on Reaction 1, 4 mol CO(g) forms 2 mol of gases. Because of the direct relationship between P and n at constant V and T, that means 1.0 atm CO(g) makes 0.50 atm of gases.

Based on the passage, which factor(s) was(were) likely to have influenced the size of New York's garment district? Great and unanticipated increases in manufacturing by competitor countries bumped the United States out of the lead. E-mail and inexpensive long-distance phone calls made it less necessary to be in close physical proximity to others in the industry. Flights to and from the United States increased in frequency and speed, while simultaneously decreasing in price. A. I only B. II only C. I and III only D. II and III only

D. Both options II and III are supported as factors influencing the size of New York City's garment district. The author says: "suffice it to say, advances in communications and transportation diminished New York City's inherent geographic advantage in manufacturing" (paragraph 2). Option III is an example of an advance in transportation, while II is an advance in communication.

In which of the following cellular locations does EPO most likely initially bind EPOR in erythrocyte precursor cells? A. Cytosol B. Endoplasmic reticulum C. Nucleus D. Plasma membrane

D. EPO, being a glycoprotein, cannot cross the cell membrane. Consequently, it is likely that EPOR is located on the surface of the plasma membrane.

In contrast to chemical messengers in classical endocrine signaling systems, chemical messengers in paracrine and autocrine signaling systems are: A. secreted by neurons only. B. not likely to bind cell receptors. C. usually transported by ducts. D. not transported by blood vessels.

D. Endocrine signals are released into the blood in order to impact tissues scattered throughout the body. By contrast, paracrine and autocrine chemical messengers act locally. Paracrine chemical messengers act on cells near the cell that secretes the messenger, and autocrine chemical messengers act on the same cell that secretes the messenger. Therefore, paracrine and autocrine factors do not need to be taken up in the blood to act on distant tissues.

What quantity of Compound 1 must be provided to prepare 100.00 mL of solution with a concentration equal to Ki? A. 48.4 mg B. 24.2 mg C. 5.64 mg D. 2.92 mg

D. In 100.00 mL solution, 60.3 μM Compound 1 contains 6.03 μmol, which when converted to mol and multiplied by the molar mass, yields 0.00292 g or 2.92 mg.

A graph of miRNA/RNA denaturation versus melting temperature is shown. The arrow in the graph indicates the curve representing the melting temperature for which miRNA, assuming 100% base complementarity with its target sequence? A. miR-142-5p B. miR-223 C. miR-10b D. miR-30a-3p

D. In nucleic acid duplex structures, higher GC-content correlates with more stable duplex and thus higher melting temperature. miR-30a-3p has 11 G+C, and comparatively has the highest GC-content than the other miRs.

In response to changing glucose levels, which events occur at time points A and B? A. Hepatocytes secrete glucagon at point A, and the pancreatic alpha cells secrete insulin at point B. B. Pancreatic alpha cells secrete glucagon at point A, and pancreatic beta cells secrete insulin at point B. C. Pancreatic alpha cells secrete insulin at point A, and hepatocytes secrete glucagon at point B. D. Pancreatic beta cells secrete insulin at point A, and pancreatic alpha cells secrete glucagon at point B.

D. Insulin is secreted in response to high blood glucose levels (point A) by pancreatic beta cells. Conversely, glucagon is secreted in response to low blood glucose levels (point B) from pancreatic alpha cells.

Based on the passage, which of the following is closest to the pressure exerted on the chest by a 10 × 5 cm rectangular paddle during defibrillation? (Note: 1 Pa = 1 N/m2.) A. 5 kPa B. 10 kPa C. 15 kPa D. 20 kPa

D. Pressure is the ratio of the force applied perpendicular to a surface and the area of the surface. Because the normal component of the force is 100 N and the area is 10 cm × 5 cm = 50 cm2 = 0.005 m2, the pressure is (100 N)/(0.005 m2) = 20 kPa.

Based on the passage, the "many blues tourists" referred to in paragraph 4 seek an experience most like: A. that of theater-goers who prefer to see plays performed in the language they were written in. B. that of film-goers who generally attend more popular films before they see more obscure films. C. that of sports fans who attend professional sporting events but rarely watch them on television. D. that of viewers who prefer to see artists' drawings that were never advertised for sale.

D. The "many tourists" mentioned in the passage seek a blues culture "apparently untainted by the more commercial aspects of marketing and tourism" (paragraph 4). This is the only option that mentions an interest in something that is not for sale.

If the small bumps seen when half of the membrane is peeled away were chemically shown to consist of the lipid cholesterol, how would the Fluid Mosaic Model have to be modified? A. The proteins would have to be embedded less than halfway through the membrane. B. There could be no proteins in the membrane. C. The lipids would have to be embedded in the proteins. D. It would not necessarily have to be altered, but there would be less evidence supporting it.

D. The Fluid Mosaic Model indicates that the hydrophilic regions of proteins are found on the membrane surfaces, while the hydrophobic regions are buried among phospholipid tails. This arrangement allows proteins to span the membrane. Consistently, the passage mentions that, upon peeling back the top membrane layer, small bumps are observed. This is consistent with the idea that proteins span the membrane. If these bumps were identified as cholesterol, this does not necessarily disprove the model. Instead, it is possible that membrane-spanning proteins remain adhered to the leaflet that has been peeled back.

Which physical property does NOT change with the amino acid substitution made in TPMT*5? A. Molecular weight B. Hydrophobicity C. Hydrogen bonding capability D. Net charge

D. The L49S variant (TPMT*5) has the same charge as wild-type TPMT because the amino acid residues do not have charge.

Which statement would most weaken the likelihood that the MIYO system would help to create evidence-based public health solutions? A. The targeted users of the MIYO system are public health organizations rather than individuals. B. Incorporating the use of the Internet is not the only way to apply the long tail approach to public health interventions. C. The MIYO system does not necessarily make the goal of "blockbuster" interventions less desirable. D. Many public health challenges require social or political solutions that digital products and information alone cannot provide.

D. The MIYO system is intended to address public health challenges, and the MIYO system depends on digital products and information. So if digital products and information cannot necessarily provide responses to "many public health challenges," this would clearly weaken the chance that MIYO could help to create the necessary solutions.

For which of the following assertions does the author provide an explanation in the passage? A. "More women than men came..." B. "The American government preferred to ignore the rest." C. "This migration had serious social and political consequences..." D. "Many [resisters] who entered elsewhere wound up in Toronto"

D. The author gives several reasons as to why many of the resisters/migrants eventually moved to Toronto: "Vancouver's labor force was tightly unionized, making jobs hard to find, and Montreal presented language problems. English-speaking and increasingly cosmopolitan Toronto became the place of settlement for the largest number of American resisters" (paragraph 4).

Why does the author most likely emphasize that "the work must be seen up close, slowly, canvas by canvas" (paragraph 3)? A. To explain the lack of museum exhibitions of Monet's series works B. To suggest that Monet's work contains imperfections C. To indicate how the paradoxes in Monet's work can be understood D. To support a claim regarding the value of Monet's work

D. The author recommends looking closely and slowly in order to see the detail, and it is in the detail that the author sees the value of Monet's work (paragraph 3 and especially final paragraph).

Based on information in the passage, one could predict that which of the following people would experience the LEAST amount of stress? A. A businessperson whose partner has taken charge of all major decisions B. A soldier whose daily routine is tightly structured and controlled by superiors C. A chronically ill patient whose physician makes all the decisions about the patient's treatment D. An athlete whose coach expects input from team players on which play or strategy to employ

D. The author writes that "Compared with individuals who perceive they have low control, individuals who perceive they have high control will be less likely to interpret the environment as stressful . . ." (final paragraph). The person described in this option, who is part of a team where the members' "input" is expected and presumably welcomed by the coach, would thus be likely to exhibit less stress than the people described in each of the other options, none of whom are given decision-making power or input.

How many moles of NaCl were contained in 500 mL of the buffer solution used to elute hMPRα? A. 7.5 x 10^-3 B. 3.0 x 10^-3 C. 3.0 x 10^-2 D. 1.5 x10^-1

D. The concentration of NaCl in the buffer solutions was 300 mM. The amount of NaCl contained in 500 mL can be calculated as: 300 mmol/L × 500 mL × 1L/1000 mL = 150 mmol = 150 × 10-3 mol = 1.5 × 10-1 mol.

Blood flows with a speed of 30 cm/s along a horizontal tube with a cross-section diameter of 1.6 cm. What is the blood flow speed in the part of the same tube that has a diameter of 0.8 cm? A. 7.5 cm/s B. 15 cm/s C. 60 cm/s D. 120 cm/s

D. The flow is characterized by the continuity equation because no amount of blood is lost between the two locations. The continuity equation is 30 cm/s × π × ((1.6 cm)/2)2 = v × π × ((0.8 cm)/2)2. Solving for v yields v = 4 × 30 cm/s = 120 cm/s.

The ligand of hMPRα is derived from which compound? A. Glucose B. Phenylalanine C. Glycerol D. Cholesterol

D. The ligand for hMPRα is the steroid progesterone. Steroids are a class of lipids that are derived from cholesterol.

Based on the passage, to which phylum does Enterobacter most likely belong? A. Actinobacteria B. Firmiculate C. Bacteroidete D. Proteobacteria

D. The passage indicates that gram-negative Proteobacteriaare increased in CD-affected individuals at the expense of Firmiculates. The table shows that Enterobacter is a gram-negative bacterium that is increased during CD, suggesting that is it a Proteobacterium.

A major obstacle to obtaining useful energy from a nuclear fusion reactor is containment of the fuel at the very high temperatures required for fusion. The reason such high temperatures are required is to: A. eliminate the strong nuclear force. B. remove electrical charge from reactants. C. decrease the density of the fuel. D. enable reactants to approach within range of the strong nuclear force.

D. The probability of fusion increases with the decrease in the average distance between fuel particles that enables attractive nuclear forces to overcome the repelling nuclear forces acting at medium and long distances. An increase in the temperature is equivalent to an increase in the root-mean-square speed of the fuel particles that will travel the average distance between fuel reactants in smaller times. The associated increase in the kinetic energy of the particles relative to the center of mass of the nuclear fuel system essentially correlates with a decrease in the electrostatic potential barrier that repels particles of the same electric charge. In turn, this increases the probability of particles to undergo the tunnel effect by penetrating the electrostatic barrier. These combined effects enable reactants to approach within range of the strong nuclear force.

One of the silent SNPs present in the Northwestern European haplotype that is associated with LP resides within the lactase gene. Genomic DNA and cDNA of the region containing this SNP in an LP heterozygous adult was sequenced. The sequence results are shown. The SNP resulted from what type of mutation? A. Purine to purine B. Purine to pyrimidine C. Pyrimidine to purine D. Pyrimidine to pyrimidine

D. The radiograph indicates an SNP containing both a cytosine and thymine nucleotide, instead of just thymine. Since both nucleobases are pyrimidines, this indicates that the SNP resulted from the mutation of a pyrimidine to another pyrimidine.

What is the ratio of cation to enzyme in the spectroelectrochemical experiments described in the passage?

D. The ratio can be found by noting that the enzyme concentration was 0.75 mM, while the concentration of cations was 0.150 M = 150 mM. The ratio is therefore 200:1.

A particular diploid organism is heterozygous in each of 3 unlinked genes. Considering only these 3 genes, how many different types of gametes can this organism produce? A. 3 B. 4 C. 6 D. 8

D. There are 8 distinct gametes that can be formed from an diploid organism that is heterozygous at three unlinked genes. Each gene (A, B, and C) will have two alleles (1 and 2) which can be termed: A1, A2, B1, B2, C1, and C2. The resulting gamete combinations will be: A1, B1, C1; A1, B2, C1; A1, B2, C2; A1, B1, C2; A2, B1, C1; A2, B2, C1; A2, B2, C2; A2, B1, C2.

Approximately how many moles of Kr+ are contained in the laser tube at 0°C and 1 atm? A. 3 x 10^-7 B. 2 x 10^-6 C. 4 x 10^-5 D. 5 x 10^-4

D. There is 1 mole of gas in a volume of 22.4 L = 2.24 x 10^4 cm^3 at STP; there are approximately 5 x 10^-4 moles in 11 cm^3.

In an enzyme-catalyzed reaction where enzyme concentration is held constant and substrate concentration is relatively low, which kinetic parameter will increase with the addition of more substrate? (Note: Other than substrate concentration, assume no other changes to reaction conditions.) A. KM B. kcat C.Vmax D.V0

D. V0 is the initial velocity of an enzymatic reaction. At low concentrations of substrate and constant enzyme concentration, adding more substrate will increase V0 until the maximal velocity is reached.

The term "Copernican revolution" refers to the demonstration by Copernicus that the apparent daily orbiting of Earth by the Sun is illusory and that Earth actually orbits the Sun. In applying this term to a different phenomenon (paragraph 4), what idea does the author evidently mean to imply? A. An object that is designed according to engineering principles is as real as a scientific finding. B. A project that may result in an object remains an illusion until its feasibility is demonstrated. C. When an object results from a technological project, it becomes equivalent to a natural object. D. When humans must adapt to an object designed by humans, the source of control has reversed.

D. With the reference to the Copernican revolution, the illusion of an earth-centered cosmos is compared to human control over an object still in the conceptual and drafting stages of an engineering project: humans at this point control the object. When the object is created and exists in the physical world, the direction of control and influence reverses and the object now influences humans: "But once the project is realized and the object real, it is people, outside their offices, who are influenced by it—a Copernican revolution" (paragraph 4).

Consider the fully protonated amino acid shown. As the pH of a solution of this amino acid is raised, which group deprotonates first? A.I B.II C.III D.IV

a. As the pH is raised, the most acidic group deprotonates first. Of the choices, two are carboxylic acids, one is a hydroxyl group, and one is a protonated amine. The hydroxyl group is least acidic, while the protonated amine is less acidic (pKa ~ 10) than a carboxylic acid group (pKa ~ 5). Of the two carboxylic acid groups, the one next to the chlorine atoms will be more acidic since its conjugate base (an anion) will be stabilized by an inductive effect which dissipates negative charge building up.