Medical Tests Medical Tests Certifications MCAT-TEST Questions & Answers

• Question 791:

  Muzak, the intentionally unobtrusive music that most people associate with elevators and dentists' waiting rooms, represents the paradoxical success story of a product designed to be ignored. Although few people admit to enjoying its blandly melodic sounds, Muzak reaches over 100 million listeners in 14 countries and has played in the White House, the Apollo lunar spacecraft, and countless supermarkets, offices, and factories. This odd combination of criticism and widespread acceptance is not surprising, however, when one considers that Muzak is not created for the enjoyment of its listeners: rather, its purpose is to modify physiological and psychological aspects of an environment. In the workplace, Muzak is credited with increasing both productivity and profitability. Research into the relationship between music and productivity can be traced to the earliest days of the Muzak Corporation. Developed by a military officer in 1922 as a way of transmitting music through electrical wires, Muzak blossomed in the 1930's following a study which reported that people work harder when they listen to certain kinds of music. Impressed by these findings, the BBC began to broadcast music in English munitions factories during World War II in an effort to combat fatigue. When workers assembling weapons increased their output by 6 percent, the U.S. War Production Board contracted the Muzak Corporation to provide uplifting music to American factories. Today, the corporation broadcasts its "Environmental Music" to countless businesses and institutions throughout the world. And while most people claim to dislike Muzak's discreet cadences, it seems to positively influence both productivity and job satisfaction.

  Researchers speculate that listening to Muzak and other soft music improves morale and reduces stress by modifying our physiology. Physiological changes such as lowered heart rate and decreased blood pressure have been documented in hospital studies testing the effect of calming music on cardiac patients. In addition, certain kinds of music seem to effect one's sense of emotional, as well as physical, well being. It is just this sort of satisfaction which is thought to result in increased performance in the workplace. In a study of people performing repetitive clerical tasks, those who listened to music performed more accurately and quickly than those who worked in silence; those who listened to Muzak did better still. Moreover, while Muzak was conceived as a tool for productivity, it also seems to influence a business' profitability. In an experiment in which supermarket shoppers shopped to the mellow sounds of Muzak, sales were increased by as much as 12 percent. What makes Muzak unique is a formula by which familiar tunes are modified and programmed. Careful instrumentation adds to an overall sound that is neither monotonous nor rousing. But it is the precisely timed programming that separates Muzak from other "easy listening" formats. At the core of the programming is the concept of the "Stimulus Progression". Muzak programs are divided into quarter-hour groupings of songs, and are specifically planned for the time of day at which they will be heard. Each composition is assigned a mood rating between 1 and 6 called a stimulus value; a song with a rating of 2, for example, is slower and less invigorating than one with a value of 5. Approximately six compositions with ascending stimulus values play during any given quarter hour; each 15-minute segment ends in silence. Each segment of a 24-hour program is carefully planned. Segments that are considered more stimulating air at 11 a.m. and 3 p.m. (the times when workers typically tire), while more soothing segments play just after lunchtime and towards the end of the day, when workers are likely to be restless.

  From the point of view of management, then, Muzak is a useful tool in the effort to maximize both productivity and profits. However, some people object to its presence, labeling it as a type of unregulated air pollution. Still others see it as an Orwellian nightmare, a manipulation of the subconscious. But Muzak's effectiveness seems to lie in the fact that most people never really listen to it. While it may be true that no one actually likes this carefully crafted aural atmosphere, many simply ignore it, allowing its forgettable sounds to soften the contours of the day.

  Of the following, the author is most interested in discussing:

  A. the origins of the Muzak Corporation.

  B. how Muzak modifies physical states and psychological atmospheres.

  C. how Muzak increases productivity in the workplace.

  D. the ways in which Muzak differs from other "easy listening" formats.

  Correct Answer: B

  This is a main idea question. This passage is mainly descriptive, not opinionated, and considers various aspects of Muzak, treating it as an unusual phenomenon. Although the second paragraph describes the history of the Muzak Corporation -- mentioned in choice (A) -- that is merely a paragraph topic, a supporting detail to the main idea of the passage. Similarly, the third paragraph discusses how Muzak increases productivity in the workplace, mentioned in (C), but that also is just one aspect of this passage, not its main focus. The passage does refer to how Muzak is different from other "easy listening'' music -- choice (D); this is discussed in the fourth paragraph, but this does not refer to the main focus of the passage either. Only choice (B) correctly addresses the author's main interest in the passage: how Muzak modifies physical states and psychological atmospheres. Only this choice reflects the broadly descriptive focus of the passage, and reflects the various paragraphs' one, unifying theme.

• Question 792:

  Muzak, the intentionally unobtrusive music that most people associate with elevators and dentists' waiting rooms, represents the paradoxical success story of a product designed to be ignored. Although few people admit to enjoying its blandly melodic sounds, Muzak reaches over 100 million listeners in 14 countries and has played in the White House, the Apollo lunar spacecraft, and countless supermarkets, offices, and factories. This odd combination of criticism and widespread acceptance is not surprising, however, when one considers that Muzak is not created for the enjoyment of its listeners: rather, its purpose is to modify physiological and psychological aspects of an environment.

  In the workplace, Muzak is credited with increasing both productivity and profitability. Research into the relationship between music and productivity can be traced to the earliest days of the Muzak Corporation. Developed by a military officer in 1922 as a way of transmitting music through electrical wires, Muzak blossomed in the 1930's following a study which reported that people work harder when they listen to certain kinds of music. Impressed by these findings, the BBC began to broadcast music in English munitions factories during World War II in an effort to combat fatigue. When workers assembling weapons increased their output by 6 percent, the U.S. War Production Board contracted the Muzak Corporation to provide uplifting music to American factories. Today, the corporation broadcasts its "Environmental Music" to countless businesses and institutions throughout the world. And while most people claim to dislike Muzak's discreet cadences, it seems to positively influence both productivity and job satisfaction.

  Researchers speculate that listening to Muzak and other soft music improves morale and reduces stress by modifying our physiology. Physiological changes such as lowered heart rate and decreased blood pressure have been documented in hospital studies testing the effect of calming music on cardiac patients. In addition, certain kinds of music seem to effect one's sense of emotional, as well as physical, well being. It is just this sort of satisfaction which is thought to result in increased performance in the workplace. In a study of people performing repetitive clerical tasks, those who listened to music performed more accurately and quickly than those who worked in silence; those who listened to Muzak did better still. Moreover, while Muzak was conceived as a tool for productivity, it also seems to influence a business' profitability. In an experiment in which supermarket shoppers shopped to the mellow sounds of Muzak, sales were increased by as much as 12 percent. What makes Muzak unique is a formula by which familiar tunes are modified and programmed. Careful instrumentation adds to an overall sound that is neither monotonous nor rousing. But it is the precisely timed programming that separates Muzak from other "easy listening" formats. At the core of the programming is the concept of the "Stimulus Progression." Muzak programs are divided into quarter-hour groupings of songs, and are specifically planned for the time of day at which they will be heard. Each composition is assigned a mood rating between 1 and 6 called a stimulus value; a song with a rating of 2, for example, is slower and less invigorating than one with a value of 5. Approximately six compositions with ascending stimulus values play during any given quarter hour; each 15 minute segment ends in silence. Each segment of a 24-hour program is carefully planned. Segments that are considered more stimulating air at 11 a.m. and 3 p.m. (the times when workers typically tire), while more soothing segments play just after lunchtime and towards the end of the day, when workers are likely to be restless.

  From the point of view of management, then, Muzak is a useful tool in the effort to maximize both productivity and profits. However, some people object to its presence, labeling it as a type of unregulated air pollution. Still others see it as an Orwellian nightmare, a manipulation of the subconscious. But Muzak's effectiveness seems to lie in the fact that most people never really listen to it. While it may be true that no one actually likes this carefully crafted aural atmosphere, many simply ignore it, allowing its forgettable sounds to soften the contours of the day.

  According to the passage, a 15-minute segment of Muzak with an average stimulus value of 5 would most likely be broadcast at:

  A. there is no known way to isolate the DNA responsible for hemoglobin.

  B. naked hemoglobin tends to break down in the bloodstream.

  C. non-globulating PFCs have significantly abbreviated oxygen-carrying capacities.

  D. the use of PFCs may lead to blood clotting.

  Correct Answer: C

  This is a detail question. The fourth paragraph discusses Muzak's programming and the concept of the "Stimulus Progression". A segment with an average stimulus value of 5 would be rather lively, since segments are rated from 1-6. Since such invigorating segments are aired at the times of day when workers are likely to tire, and the last sentence of the fourth paragraph mentions 3 p.m. as such a time, (C) is the correct answer. The last sentence of the fourth paragraph also mentions the periods of time just after lunch and towards the end of the day as times when more soothing segments play, so (A) and (D) are wrong. The passage does not say anything about what level of stimulus might be programmed in the early morning hours. Therefore, it cannot be assumed that invigorating music of a value of 5 would be played at the time indicated in choice (B).

• Question 793:

  Due to ever-increasing paranoia about the transmission of hepatitis and AIDS via blood transfusions and the frequent difficulty of procuring matching blood donors for patients, researchers have been working at a feverish pace to produce disease-free and easy-to-use blood substitutes. The difficulty most synthetic blood researches have had is in formulating a substance that combines qualities of sterility, high capacity for carrying oxygen to body tissues, and versatility within the human body. Three major substitute technologies have been developed to date; each has certain advantages and shortcomings.

  "Red blood," the first of the blood substitute technologies, is derived from hemoglobin which has been recycled from old, dead, or worn-out red blood cells and modified so that it can carry oxygen outside the red blood cell. Hemoglobin, a complex protein, is the blood's natural oxygen carrier and is attractive to scientists for use in synthetic blood because of its oxygen-carrying capacity. However, hemoglobin can sometimes constitute a two-fold threat to humans when it is extracted from the red blood cell and introduced to the body in its naked form. First, hemoglobin molecules are rarely sterile and often remain contaminated by viruses to which they were exposed in the cell. Second, naked hemoglobin is extremely dangerous to the kidneys, causing blood flow at these organs to shut down and leading, ultimately, to renal failure. Additional problems arise from the fact that hemoglobin is adapted to operate optimally within the intricate environment of the red blood cell. Stripped of the protection of the cell, the hemoglobin molecule tends to suffer breakdown within several hours. Although modification has produced more durable hemoglobin molecules which do not cause renal failure, undesired side effects continue to plague patients and hinder the development of hemoglobin-based blood substitutes.

  Another synthetic blood alternative, "white blood", is dependent on laboratory synthesized chemicals called perfluorocarbons (PFCs). Unlike blood, PFCs are clear oil like liquids, yet they are capable of absorbing quantities of oxygen up to 50% of their volume, enough of an oxygen carrying potential for oxygen-dependent organisms to survive submerged in the liquid for hours by "breathing" it. Although PFCs imitate real blood by effectively absorbing oxygen, scientists are primarily interested in them as constituents of blood substitutes because they are inherently safer to use than hemoglobin-based substitutes. PFCs do not interact with any chemicals in the body and can be manufactured in near-perfect sterility. The primary pitfall of PFCs is in their tendency to form globules in plasma that can block circulation. Dissolving PFCs in solution can mitigate globulation; however, this procedure also seriously curtails the PFCs' oxygen capacity.

  The final and perhaps most ambitious attempt to form a blood substitute involves the synthesis of a modified version of human hemoglobin by genetically-altered bacteria. Fortunately, this synthetic hemoglobin seems to closely mimic the qualities of sterility, and durability outside the cellular environment, and the oxygen-carrying efficiency of blood. Furthermore, researchers have found that if modified hemoglobin genes are added to bacterial DNA, the bacteria will produce the desired product in copious quantities. This procedure is extremely challenging, however, because it requires the isolation of the human gene for the production of hemoglobin, and the modification of the gene to express a molecule that works without support from a living cell.

  While all the above technologies have serious drawbacks and difficulties, work to perfect an ideal blood substitute continues. Scientists hope that in the near future safe synthetic blood transfusions may ease blood shortages and resolve the unavailability of various blood types.

  It can be inferred from the passage that the difficulty of producing an ideal blood substitute is compounded by all of the following EXCEPT:

  A. there is no known way to isolate the DNA responsible for hemoglobin.

  B. naked hemoglobin tends to break down in the bloodstream.

  C. non-globulating PFCs have significantly abbreviated oxygen-carrying capacities.

  D. the use of PFCs may lead to blood clotting.

  Correct Answer: A

  This is an inference question. It asks which of the answer choices is not a factor that detracts from the production of an ideal blood substitute. Choices (C) and (D) present troublesome aspects of PFCs. The end of the second paragraph establishes that one of the drawbacks of PFCs is that they form globules, blocking blood circulation, choice (D). In order to bypass this problem, scientists have attempted to modify PFCs so that they do not form globules. These efforts have been thwarted, however, as such modified PFCs have curtailed oxygen-carrying capacities, choice (C). Choice (B) relates to problems with "red blood". The third sentence of the second paragraph tells us that one of the problems of "red blood" is that its naked hemoglobin breaks down rapidly in the bloodstream. Choice (B), then, is a factor that has compounded the difficulty of producing an ideal blood substitute. Choice (A) presents a statement which, if supported by the passage, might very well compound the difficulties of producing an ideal synthetic blood. If there was no known way to isolate the DNA responsible for hemoglobin, then genetic engineering of modified hemoglobin, would be hampered. But the passage never states that there is no known way to isolate the DNA responsible for hemoglobin. It does mention, in the last sentence of the fourth paragraph, that genetic engineering is challenging because it requires the isolation of the human gene for the production of hemoglobin. But the passage does not say that there is no known way to do this. Choice (A), therefore, is not suggested as a complication in the production of synthetic blood and is the correct answer.

• Question 794:

  Due to ever-increasing paranoia about the transmission of hepatitis and AIDS via blood transfusions and the frequent difficulty of procuring matching blood donors for patients, researchers have been working at a feverish pace to produce disease-free and easy-to-use blood substitutes. The difficulty most synthetic blood researches have had is in formulating a substance that combines qualities of sterility, high capacity for carrying oxygen to body tissues, and versatility within the human body. Three major substitute technologies have been developed to date; each has certain advantages and shortcomings.

  "Red blood," the first of the blood substitute technologies, is derived from hemoglobin which has been recycled from old, dead, or worn-out red blood cells and modified so that it can carry oxygen outside the red blood cell. Hemoglobin, a complex protein, is the blood's natural oxygen carrier and is attractive to scientists for use in synthetic blood because of its oxygen-carrying capacity. However, hemoglobin can sometimes constitute a two-fold threat to humans when it is extracted from the red blood cell and introduced to the body in its naked form. First, hemoglobin molecules are rarely sterile and often remain contaminated by viruses to which they were exposed in the cell. Second, naked hemoglobin is extremely dangerous to the kidneys, causing blood flow at these organs to shut down and leading, ultimately, to renal failure. Additional problems arise from the fact that hemoglobin is adapted to operate optimally within the intricate environment of the red blood cell. Stripped of the protection of the cell, the hemoglobin molecule tends to suffer breakdown within several hours. Although modification has produced more durable hemoglobin molecules which do not cause renal failure, undesired side effects continue to plague patients and hinder the development of hemoglobin-based blood substitutes.

  Another synthetic blood alternative, "white blood", is dependent on laboratory synthesized chemicals called perfluorocarbons (PFCs). Unlike blood, PFCs are clear oil like liquids, yet they are capable of absorbing quantities of oxygen up to 50% of their volume, enough of an oxygen carrying potential for oxygen-dependent organisms to survive submerged in the liquid for hours by "breathing" it. Although PFCs imitate real blood by effectively absorbing oxygen, scientists are primarily interested in them as constituents of blood substitutes because they are inherently safer to use than hemoglobin-based substitutes. PFCs do not interact with any chemicals in the body and can be manufactured in near-perfect sterility. The primary pitfall of PFCs is in their tendency to form globules in plasma that can block circulation. Dissolving PFCs in solution can mitigate globulation; however, this procedure also seriously curtails the PFCs' oxygen capacity.

  The final and perhaps most ambitious attempt to form a blood substitute involves the synthesis of a modified version of human hemoglobin by genetically-altered bacteria. Fortunately, this synthetic hemoglobin seems to closely mimic the qualities of sterility, and durability outside the cellular environment, and the oxygen-carrying efficiency of blood. Furthermore, researchers have found that if modified hemoglobin genes are added to bacterial DNA, the bacteria will produce the desired product in copious quantities. This procedure is extremely challenging, however, because it requires the isolation of the human gene for the production of hemoglobin, and the modification of the gene to express a molecule that works without support from a living cell.

  While all the above technologies have serious drawbacks and difficulties, work to perfect an ideal blood substitute continues. Scientists hope that in the near future safe synthetic blood transfusions may ease blood shortages and resolve the unavailability of various blood types.

  According to the passage, how much oxygen can be absorbed by a 300 cc sample of PFC?

  A. 50 cc

  B. 100 cc

  C. 150 cc D. 300 cc

  Correct Answer: C

  This is an application question which requires you to apply information from the passage to solve a problem. The passage mentions that PFCs are capable of absorbing quantities of oxygen up to 50% of their volume. Applying this information, then, a 300 cc sample of PFC can absorb up to 150 cc, 50% of 300 cc. The correct answer, then, is choice (C), 150 cc.

• Question 795:

  Due to ever-increasing paranoia about the transmission of hepatitis and AIDS via blood transfusions and the frequent difficulty of procuring matching blood donors for patients, researchers have been working at a feverish pace to produce disease-free and easy-to-use blood substitutes. The difficulty most synthetic blood researches have had is in formulating a substance that combines qualities of sterility, high capacity for carrying oxygen to body tissues, and versatility within the human body. Three major substitute technologies have been developed to date; each has certain advantages and shortcomings.

  "Red blood," the first of the blood substitute technologies, is derived from hemoglobin which has been recycled from old, dead, or worn-out red blood cells and modified so that it can carry oxygen outside the red blood cell. Hemoglobin, a complex protein, is the blood's natural oxygen carrier and is attractive to scientists for use in synthetic blood because of its oxygen-carrying capacity. However, hemoglobin can sometimes constitute a two-fold threat to humans when it is extracted from the red blood cell and introduced to the body in its naked form. First, hemoglobin molecules are rarely sterile and often remain contaminated by viruses to which they were exposed in the cell. Second, naked hemoglobin is extremely dangerous to the kidneys, causing blood flow at these organs to shut down and leading, ultimately, to renal failure. Additional problems arise from the fact that hemoglobin is adapted to operate optimally within the intricate environment of the red blood cell. Stripped of the protection of the cell, the hemoglobin molecule tends to suffer breakdown within several hours. Although modification has produced more durable hemoglobin molecules which do not cause renal failure, undesired side effects continue to plague patients and hinder the development of hemoglobin-based blood substitutes.

  Another synthetic blood alternative, "white blood", is dependent on laboratory synthesized chemicals called perfluorocarbons (PFCs). Unlike blood, PFCs are clear oil like liquids, yet they are capable of absorbing quantities of oxygen up to 50% of their volume, enough of an oxygen carrying potential for oxygen-dependent organisms to survive submerged in the liquid for hours by "breathing" it. Although PFCs imitate real blood by effectively absorbing oxygen, scientists are primarily interested in them as constituents of blood substitutes because they are inherently safer to use than hemoglobin-based substitutes. PFCs do not interact with any chemicals in the body and can be manufactured in near-perfect sterility. The primary pitfall of PFCs is in their tendency to form globules in plasma that can block circulation. Dissolving PFCs in solution can mitigate globulation; however, this procedure also seriously curtails the PFCs' oxygen capacity.

  The final and perhaps most ambitious attempt to form a blood substitute involves the synthesis of a modified version of human hemoglobin by genetically-altered bacteria. Fortunately, this synthetic hemoglobin seems to closely mimic the qualities of sterility, and durability outside the cellular environment, and the oxygen-carrying efficiency of blood. Furthermore, researchers have found that if modified hemoglobin genes are added to bacterial DNA, the bacteria will produce the desired product in copious quantities. This procedure is extremely challenging, however, because it requires the isolation of the human gene for the production of hemoglobin, and the modification of the gene to express a molecule that works without support from a living cell. While all the above technologies have serious drawbacks and difficulties, work to perfect an ideal blood substitute continues. Scientists hope that in the near future safe synthetic blood transfusions may ease blood shortages and resolve the unavailability of various blood types.

  Which of the following is mentioned in the passage as a problem specific to "red blood"?

  A. "Red blood" cannot be produced in large enough quantities.

  B. "Red blood" tends to form globules that block circulation.

  C. Hemoglobin does not carry oxygen effectively.

  D. "Red blood" exhibits poor durability in the bloodstream.

  Correct Answer: D

  This is a detail question that requires you to recall which of the answer choices is a problem specific to "red blood". Since "red blood" is discussed in the second paragraph of the passage, refer there for details. Choice (A) is incorrect because the passage never says that "red blood cannot be produced in large quantities". In fact, the passage never at all mentions the extent to which "red blood" can be produced. The passage only mentions quantities of production of synthetic blood in the third sentence of the fourth paragraph, where it states, in reference to genetically- altered hemoglobin, that "the bacteria will produce the desired product in copious quantities". Since the passage never mentions (A), it cannot be a problem specific to "red blood". Similarly, choice (B) distorts a detail of the passage which relates to another type of synthetic blood. The passage mentions in the fourth sentence of the third paragraph that the primary pitfall of PFCs is their tendency to form globules. The passage never says that "red blood'' forms globules. Choice (C) also is not a true statement. The second sentence of the second paragraph states that hemoglobin is the blood's natural oxygen carrier and, in fact, is attractive to scientists precisely because of its oxygen-carrying capacity. You may safely conclude from this information, then, that hemoglobin does, indeed, carry oxygen effectively and (C) is not a problem at all. Only choice (D), which states that "red blood exhibits poor durability in the bloodstream", is mentioned in the passage as a problem specific to "red blood". In the second paragraph, the passage states that "additional problems arise from the fact that hemoglobin is adapted to operate optimally within the...cell. Stripped of the protection of the cell, the hemoglobin molecule tends to suffer breakdown within several hours". One of the criteria for a successful blood substitute is that it be durable and versatile. The fact that "red blood" breaks down readily in the bloodstream shows that "red blood" is not durable in the bloodstream. This is the problem mentioned specifically in relation to "red blood", so choice (D) is the correct answer.

• Question 796:

  Due to ever-increasing paranoia about the transmission of hepatitis and AIDS via blood transfusions and the frequent difficulty of procuring matching blood donors for patients, researchers have been working at a feverish pace to produce disease-free and easy-to-use blood substitutes. The difficulty most synthetic blood researches have had is in formulating a substance that combines qualities of sterility, high capacity for carrying oxygen to body tissues, and versatility within the human body. Three major substitute technologies have been developed to date; each has certain advantages and shortcomings.

  "Red blood," the first of the blood substitute technologies, is derived from hemoglobin which has been recycled from old, dead, or worn-out red blood cells and modified so that it can carry oxygen outside the red blood cell. Hemoglobin, a complex protein, is the blood's natural oxygen carrier and is attractive to scientists for use in synthetic blood because of its oxygen-carrying capacity. However, hemoglobin can sometimes constitute a two-fold threat to humans when it is extracted from the red blood cell and introduced to the body in its naked form. First, hemoglobin molecules are rarely sterile and often remain contaminated by viruses to which they were exposed in the cell. Second, naked hemoglobin is extremely dangerous to the kidneys, causing blood flow at these organs to shut down and leading, ultimately, to renal failure. Additional problems arise from the fact that hemoglobin is adapted to operate optimally within the intricate environment of the red blood cell. Stripped of the protection of the cell, the hemoglobin molecule tends to suffer breakdown within several hours. Although modification has produced more durable hemoglobin molecules which do not cause renal failure, undesired side effects continue to plague patients and hinder the development of hemoglobin-based blood substitutes.

  Another synthetic blood alternative, "white blood," is dependent on laboratory synthesized chemicals called perfluorocarbons (PFCs). Unlike blood, PFCs are clear oil like liquids, yet they are capable of absorbing quantities of oxygen up to 50% of their volume, enough of an oxygen carrying potential for oxygen-dependent organisms to survive submerged in the liquid for hours by "breathing" it. Although PFCs imitate real blood by effectively absorbing oxygen, scientists are primarily interested in them as constituents of blood substitutes because they are inherently safer to use than hemoglobin-based substitutes. PFCs do not interact with any chemicals in the body and can be manufactured in near-perfect sterility. The primary pitfall of PFCs is in their tendency to form globules in plasma that can block circulation. Dissolving PFCs in solution can mitigate globulation; however, this procedure also seriously curtails the PFCs' oxygen capacity.

  The final and perhaps most ambitious attempt to form a blood substitute involves the synthesis of a modified version of human hemoglobin by genetically-altered bacteria. Fortunately, this synthetic hemoglobin seems to closely mimic the qualities of sterility, and durability outside the cellular environment, and the oxygen-carrying efficiency of blood. Furthermore, researchers have found that if modified hemoglobin genes are added to bacterial DNA, the bacteria will produce the desired product in copious quantities. This procedure is extremely challenging, however, because it requires the isolation of the human gene for the production of hemoglobin, and the modification of the gene to express a molecule that works without support from a living cell.

  While all the above technologies have serious drawbacks and difficulties, work to perfect an ideal blood substitute continues. Scientists hope that in the near future safe synthetic blood transfusions may ease blood shortages and resolve the unavailability of various blood types.

  We can infer that all of the synthetic blood technologies discussed in this passage:

  A. sustain submerged oxygen-dependent organisms.

  B. possess high oxygen-carrying capacities.

  C. maintain high standards of sterility.

  D. exhibit versatility in the human body

  Correct Answer: B

  This is an inference question that asks you to identify a common trait of all synthetic bloods. Choice (A) states that all of the synthetic bloods discussed in the passage sustain submerged oxygen-dependent organisms. The second sentence of the third paragraph notes that PFCs possess this ability, but there is no suggestion of this in reference to any of the other blood substitutes. So choice (A) is wrong. Choice (C) is incorrect because, even though all synthetic bloods should have high levels of sterility, the passage explicitly states that the naked hemoglobin molecules of "red blood" are "rarely sterile and often remain contaminated by viruses to which they were exposed in the cell". Not all blood substitutes, then, maintain high standards of sterility. Finally, choice (D) is wrong in stating that all synthetic bloods exhibit versatility in the body. The passage makes clear that not all blood substitutes are particularly versatile. For one thing, the naked hemoglobin of "red blood'' breaks down in the blood stream within several hours. Furthermore, PFCs tend to form globules, blocking blood circulation. Only choice (B) is mentioned in reference to all synthetic blood technologies. The second sentence of the second paragraph states that hemoglobin, the chief component of "red blood", is "attractive to scientists...because of its oxygen-carrying capacity". The second sentence of the third paragraph implies that PFCs have high oxygen-carrying capacities as it mentions that PFCs can absorb oxygen up to quantities 50% its volume. The author goes on to note, in the following sentence, that PFCs imitate real blood by effectively absorbing oxygen. Finally, the passage explicitly states in the second sentence of the fourth paragraph that the synthetic hemoglobin produced by genetically-altered bacteria "closely mimic(s)...(the) oxygen-carrying efficiency of blood". Choice (B), then, is the correct answer.

• Question 797:

  Due to ever-increasing paranoia about the transmission of hepatitis and AIDS via blood transfusions and the frequent difficulty of procuring matching blood donors for patients, researchers have been working at a feverish pace to produce disease-free and easy-to-use blood substitutes. The difficulty most synthetic blood researches have had is in formulating a substance that combines qualities of sterility, high capacity for carrying oxygen to body tissues, and versatility within the human body. Three major substitute technologies have been developed to date; each has certain advantages and shortcomings.

  "Red blood," the first of the blood substitute technologies, is derived from hemoglobin which has been recycled from old, dead, or worn-out red blood cells and modified so that it can carry oxygen outside the red blood cell. Hemoglobin, a complex protein, is the blood's natural oxygen carrier and is attractive to scientists for use in synthetic blood because of its oxygen-carrying capacity. However, hemoglobin can sometimes constitute a two-fold threat to humans when it is extracted from the red blood cell and introduced to the body in its naked form. First, hemoglobin molecules are rarely sterile and often remain contaminated by viruses to which they were exposed in the cell. Second, naked hemoglobin is extremely dangerous to the kidneys, causing blood flow at these organs to shut down and leading, ultimately, to renal failure. Additional problems arise from the fact that hemoglobin is adapted to operate optimally within the intricate environment of the red blood cell. Stripped of the protection of the cell, the hemoglobin molecule tends to suffer breakdown within several hours. Although modification has produced more durable hemoglobin molecules which do not cause renal failure, undesired side effects continue to plague patients and hinder the development of hemoglobin-based blood substitutes.

  Another synthetic blood alternative, "white blood," is dependent on laboratory synthesized chemicals called perfluorocarbons (PFCs). Unlike blood, PFCs are clear oil like liquids, yet they are capable of absorbing quantities of oxygen up to 50% of their volume, enough of an oxygen carrying potential for oxygen-dependent organisms to survive submerged in the liquid for hours by "breathing" it. Although PFCs imitate real blood by effectively absorbing oxygen, scientists are primarily interested in them as constituents of blood substitutes because they are inherently safer to use than hemoglobin-based substitutes. PFCs do not interact with any chemicals in the body and can be manufactured in near-perfect sterility. The primary pitfall of PFCs is in their tendency to form globules in plasma that can block circulation. Dissolving PFCs in solution can mitigate globulation; however, this procedure also seriously curtails the PFCs' oxygen capacity.

  The final and perhaps most ambitious attempt to form a blood substitute involves the synthesis of a modified version of human hemoglobin by genetically-altered bacteria. Fortunately, this synthetic hemoglobin seems to closely mimic the qualities of sterility, and durability outside the cellular environment, and the oxygen-carrying efficiency of blood. Furthermore, researchers have found that if modified hemoglobin genes are added to bacterial DNA, the bacteria will produce the desired product in copious quantities. This procedure is extremely challenging, however, because it requires the isolation of the human gene for the production of hemoglobin, and the modification of the gene to express a molecule that works without support from a living cell.

  While all the above technologies have serious drawbacks and difficulties, work to perfect an ideal blood substitute continues. Scientists hope that in the near future safe synthetic blood transfusions may ease blood shortages and resolve the unavailability of various blood types.

  According to the passage, all of the following are reasons for research into the development of synthetic bloods EXCEPT:

  A. dangerous diseases can be transmitted by conventional blood transfusions.

  B. synthetic bloods have greater oxygen-carrying capacities than naturally-produced human blood.

  C. donor blood is sometimes in short supply.

  D. certain blood types are not readily available.

  Correct Answer: B

  This requires the recollection of the reasons for synthetic blood research, discussed in the first paragraph of the passage, and infer which of the answer choices is not a reason for such research. Choice (A) suggests that patients fear the transmission of dangerous diseases such as AIDS, via blood transfusions. This fear is mentioned in the opening sentence of the passage as one of the primary reasons for the desire to develop clean, sterile, blood substitutes. Choice (A), therefore, is a reasons for the development of synthetic bloods, and does not answer this question stem correctly. Choices (C) and (D) mention different aspects of the problem of procuring matching blood donors for patients, also described in the opening sentence as one of the reasons for the development of synthetic bloods. (C) and (D), then, do not correctly complete the question stem either. Choice (B) suggests that synthetic bloods have greater oxygen- carrying capacities than naturally-produced human blood. This is not supported anywhere in the passage. The passage emphasizes that synthetic bloods should have high oxygen-carrying capacities, but there is no suggestion that synthetic bloods have higher oxygen-carrying capacities than blood.

• Question 798:

  Due to ever-increasing paranoia about the transmission of hepatitis and AIDS via blood transfusions and the frequent difficulty of procuring matching blood donors for patients, researchers have been working at a feverish pace to produce disease-free and easy-to-use blood substitutes. The difficulty most synthetic blood researches have had is in formulating a substance that combines qualities of sterility, high capacity for carrying oxygen to body tissues, and versatility within the human body. Three major substitute technologies have been developed to date; each has certain advantages and shortcomings. "Red blood," the first of the blood substitute technologies, is derived from hemoglobin which has been recycled from old, dead, or worn-out red blood cells and modified so that it can carry oxygen outside the red blood cell. Hemoglobin, a complex protein, is the blood's natural oxygen carrier and is attractive to scientists for use in synthetic blood because of its oxygen-carrying capacity. However, hemoglobin can sometimes constitute a two-fold threat to humans when it is extracted from the red blood cell and introduced to the body in its naked form. First, hemoglobin molecules are rarely sterile and often remain contaminated by viruses to which they were exposed in the cell. Second, naked hemoglobin is extremely dangerous to the kidneys, causing blood flow at these organs to shut down and leading, ultimately, to renal failure. Additional problems arise from the fact that hemoglobin is adapted to operate optimally within the intricate environment of the red blood cell. Stripped of the protection of the cell, the hemoglobin molecule tends to suffer breakdown within several hours. Although modification has produced more durable hemoglobin molecules which do not cause renal failure, undesired side effects continue to plague patients and hinder the development of hemoglobin-based blood substitutes.

  Another synthetic blood alternative, "white blood", is dependent on laboratory synthesized chemicals called perfluorocarbons (PFCs). Unlike blood, PFCs are clear oil like liquids, yet they are capable of absorbing quantities of oxygen up to 50% of their volume, enough of an oxygen carrying potential for oxygen-dependent organisms to survive submerged in the liquid for hours by "breathing" it. Although PFCs imitate real blood by effectively absorbing oxygen, scientists are primarily interested in them as constituents of blood substitutes because they are inherently safer to use than hemoglobin-based substitutes. PFCs do not interact with any chemicals in the body and can be manufactured in near-perfect sterility. The primary pitfall of PFCs is in their tendency to form globules in plasma that can block circulation. Dissolving PFCs in solution can mitigate globulation; however, this procedure also seriously curtails the PFCs' oxygen capacity.

  The final and perhaps most ambitious attempt to form a blood substitute involves the synthesis of a modified version of human hemoglobin by genetically-altered bacteria. Fortunately, this synthetic hemoglobin seems to closely mimic the qualities of sterility, and durability outside the cellular environment, and the oxygen-carrying efficiency of blood. Furthermore, researchers have found that if modified hemoglobin genes are added to bacterial DNA, the bacteria will produce the desired product in copious quantities. This procedure is extremely challenging, however, because it requires the isolation of the human gene for the production of hemoglobin, and the modification of the gene to express a molecule that works without support from a living cell.

  While all the above technologies have serious drawbacks and difficulties, work to perfect an ideal blood substitute continues. Scientists hope that in the near future safe synthetic blood transfusions may ease blood shortages and resolve the unavailability of various blood types.

  According to the passage, PFCs are helpful in the synthesis of blood substitutes because they:

  I. mimic the oxygen-carrying capacity of blood.

  II. do not react with other body chemicals.

  III.

  break down in the blood within several hours.

  A.

  I only

  B.

  II only

  C.

  I and II only

  D.

  II and III only

  Correct Answer: C

  This addresses the identification of the "helpful" aspects of PFCs. Recall that in the third paragraph, where "white blood" and PFCs are discussed. There the passage states that PFCs imitate real blood by effectively absorbing oxygen. It is true that PFCs mimic the oxygen-carrying capacity of blood, and option I will be part of the correct answer. The third and fourth sentences of the third paragraph establish that PFCs are inherently safer to use in synthetic bloods than hemoglobin is because PFCs do not interact with any chemicals in the body. Option II, therefore, also correctly completes the question stem. Finally, option III is a false statement. Nowhere does the passage suggest that PFCs breakdown in the blood within several hours. Rather, breakdown is mentioned as a problem associated with naked hemoglobin. Since option III is false, it cannot successfully complete the question stem. Only options I and II fit the question stem.

• Question 799:

  Due to ever-increasing paranoia about the transmission of hepatitis and AIDS via blood transfusions and the frequent difficulty of procuring matching blood donors for patients, researchers have been working at a feverish pace to produce disease-free and easy-to-use blood substitutes. The difficulty most synthetic blood researches have had is in formulating a substance that combines qualities of sterility, high capacity for carrying oxygen to body tissues, and versatility within the human body. Three major substitute technologies have been developed to date; each has certain advantages and shortcomings.

  "Red blood," the first of the blood substitute technologies, is derived from hemoglobin which has been recycled from old, dead, or worn-out red blood cells and modified so that it can carry oxygen outside the red blood cell. Hemoglobin, a complex protein, is the blood's natural oxygen carrier and is attractive to scientists for use in synthetic blood because of its oxygen-carrying capacity. However, hemoglobin can sometimes constitute a two-fold threat to humans when it is extracted from the red blood cell and introduced to the body in its naked form. First, hemoglobin molecules are rarely sterile and often remain contaminated by viruses to which they were exposed in the cell. Second, naked hemoglobin is extremely dangerous to the kidneys, causing blood flow at these organs to shut down and leading, ultimately, to renal failure. Additional problems arise from the fact that hemoglobin is adapted to operate optimally within the intricate environment of the red blood cell. Stripped of the protection of the cell, the hemoglobin molecule tends to suffer breakdown within several hours. Although modification has produced more durable hemoglobin molecules which do not cause renal failure, undesired side effects continue to plague patients and hinder the development of hemoglobin-based blood substitutes.

  Another synthetic blood alternative, "white blood," is dependent on laboratory synthesized chemicals called perfluorocarbons (PFCs). Unlike blood, PFCs are clear oil like liquids, yet they are capable of absorbing quantities of oxygen up to 50% of their volume, enough of an oxygen carrying potential for oxygen-dependent organisms to survive submerged in the liquid for hours by "breathing" it. Although PFCs imitate real blood by effectively absorbing oxygen, scientists are primarily interested in them as constituents of blood substitutes because they are inherently safer to use than hemoglobin-based substitutes. PFCs do not interact with any chemicals in the body and can be manufactured in near-perfect sterility. The primary pitfall of PFCs is in their tendency to form globules in plasma that can block circulation. Dissolving PFCs in solution can mitigate globulation; however, this procedure also seriously curtails the PFCs' oxygen capacity.

  The final and perhaps most ambitious attempt to form a blood substitute involves the synthesis of a modified version of human hemoglobin by genetically-altered bacteria. Fortunately, this synthetic hemoglobin seems to closely mimic the qualities of sterility, and durability outside the cellular environment, and the oxygen-carrying efficiency of blood. Furthermore, researchers have found that if modified hemoglobin genes are added to bacterial DNA, the bacteria will produce the desired product in copious quantities. This procedure is extremely challenging, however, because it requires the isolation of the human gene for the production of hemoglobin, and the modification of the gene to express a molecule that works without support from a living cell.

  While all the above technologies have serious drawbacks and difficulties, work to perfect an ideal blood substitute continues. Scientists hope that in the near future safe synthetic blood transfusions may ease blood shortages and resolve the unavailability of various blood types.

  The author mentions all of the following as weaknesses of synthetic bloods EXCEPT:

  A. naked hemoglobin can cause renal failure in humans.

  B. "red blood" can transmit viruses to a recipient.

  C. genetic engineering can be extremely difficult.

  D. "white blood" has a low oxygen-carrying potential.

  Correct Answer: D

  This is a detail question that requires you to identify the answer choice which is not a weakness of synthetic bloods. Choices (A) and (B) mention that naked hemoglobin can cause renal failure in humans and that "red blood'' can transmit viruses to a recipient. These facts are expressed in the second paragraph, which addresses red blood and the problems associated with it. The second half of that paragraph states that naked hemoglobin, the basis of "red blood", can constitute a two-fold threat to the human body as it can transmit viruses and is extremely dangerous to the kidneys, causing blood flow at these organs to shut down and results in renal failure. Choice (C) mentions that genetic engineering can be extremely difficult. Paragraph 4 is all about modified hemoglobin derived from genetically-altered bacteria. Its last sentence emphasizes the challenges associated with the to isolation and modification the human hemoglobin gene. Although, in theory, genetic engineering can produce near-ideal synthetic blood, you can infer that a drawback of this process is the complexity of these procedures. So choice (C) is also a weakness, and therefore does not complete this question stem. Choice (D) mentions that "white blood" has a low oxygen-carrying potential. Were this true, it certainly would be a weakness, as one of the chief criteria of synthetic blood is that it mimic blood in its high oxygen-carrying capacity. However, this statement is not true. The third paragraph, regarding "white blood,'' notes that PFCs, a primary component of "white blood", have high oxygen-carrying capacities. The second and third sentences of this paragraph state that PFCs are capable of absorbing quantities of oxygen up to 50% of their volume and imitate real blood by effectively absorbing oxygen. From this we can infer that "white blood'' is capable of transporting oxygen well. This contradicts choice (D). Since the passage never suggests that "white blood" has a low oxygen-carrying potential, choice (D) does not represent a weakness of synthetic blood and is the correct answer.

• Question 800:

  The time has come to acknowledge the ascendancy of the humanistic psychology movement. The so- called "Third Stream" emerged at mid-century, asserting itself against the opposition of a pair of mighty, long-established currents, psychoanalysis and behaviorism. The hostility between these two older schools, as well as divisiveness within each of them, probably helped enable humanistic psychology to survive its early years. But the movement flourished because of its wealth of insights into the nature of this most inexact science.

  Of the three major movements in the course of 20th century psychology, psychoanalysis is the oldest and most introspective. Conceived by Sigmund Freud as a means of treating mental and emotional disorders, psychoanalysis is based on the theory that people experience unresolved emotional conflicts in infancy and early childhood. Years later, although these experiences have largely disappeared from conscious awareness, they may continue to impair a person's ability to function in daily life. The patient experiences improvement when the psychoanalyst eventually unlocks these long-repressed memories of conflict and brings them to the patient's conscious awareness.

  In the heyday of behaviorism, which occurred between the two world wars, the psychoanalytic movement was heavily criticized for being too concerned with inner subjective experience. Behavioral psychologists, dismissing ideas and feelings as unscientific, tried to deal only with observable and quantifiable facts. They perceived the human being merely as an organism which generated responses to stimuli produced by its body and the environment around it. Patients' neuroses no longer needed analysis; they could instead by modified by behavioral conditioning. Not even babies were safe: B.F. Skinner devised a container in which infants could be raised under "ideal" conditions -- if a sound-proof box can be considered the ideal environment for child-rearing. By mid-century, a number of psychologists had grown dissatisfied with both the deterministic Freudian perspective and the mechanistic approach of behaviorism. They questioned the idea that human personality becomes permanently fixed in the first few years of life. They wondered if the purpose of psychology was really to reduce people to laboratory specimens. Was it not instead possible that human beings are greater than the sum of their parts? That psychology should speak to their search for fulfillment and meaning in life?

  It is questions like these that members of the Third Stream have sought to address. While the movement cannot be simplified down to a single theoretical position, it does spring from certain fundamental propositions. Humanistic psychologists believe that conscious experience, rather than outward behavior, is the proper subject of psychology. We recognize that each human being is unique, capable of change and personal growth. We see maturity as a process dependent on the establishment of a set of values and the development of self. And we believe that the more aspects of self which are satisfactorily developed, the more positive the individual's self-image.

  Abraham Maslow, a pioneer of the Third Stream, articulated a hierarchy of basic human needs, starting with food, water and air, progressing upward through shelter and security, social acceptance and belonging, to love, esteem and self-expression. Progress toward the higher stages cannot occur until all of the more basic needs have been satisfied. Individuals atop the pyramid, having developed their potential to the highest possible extent, are said to be "self-actualized".

  If this humanist theoretical perspective is aimed at empowering the individual, so too are the movement's efforts in the practical realm of clinical psychology. Believing that traditional psychotherapists tend to lead patients toward predetermined resolutions of their problems, Carl Rogers pressed for objective evaluations of both the process and outcome of psychotherapeutic treatment. Not content to function simply as a reformer, Rogers also pioneered the development of "client-centered" or nondirective therapy, which emphasizes the autonomy of the client (i.e., patient). In client-centered therapy, clients choose the subjects for discussion, and are encouraged to create their own solutions to their problems.

  Psychoanalysts and humanistic psychologists would be most likely to disagree about:

  A. the effects of internal conflicts on childhood behavior.

  B. the necessity of proper training for psychologists.

  C. the relevance and utility of clinical psychology.

  D. the significance of conscious experience.

  Correct Answer: A

  This asks the reader to identify an issue that psychoanalysts and humanistic psychologists would be most likely to disagree about. Choice A suggests the most likely point of disagreement would be the effects of internal conflicts on childhood behavior. As noted in the second sentence of paragraph 2, psychoanalytic theory places great importance on the unresolved emotional conflicts of childhood. Psychoanalysts believe that these conflicts determine, to a great extent, an individual's behavior and personality. But, according to the first two sentences of paragraph 3 and the body of paragraph 4, humanists find this psychoanalytic perspective too rigid and deterministic. While recognizing that such conflicts affect the individual's behavior, humanists believe that people of all ages are capable of changing their behavior through understanding and the effort of will. Choice A represents a point of contention and is the correct answer. There is no basis for inferring choice B. The author never discusses the subject of proper training for psychologists, whether they be psychoanalysts, behaviorists, or humanists. So it is inappropriate to say that this is the subject psychoanalysts and humanists would be "most likely" to disagree about. Choice C states that psychoanalysts and humanists would disagree about the usefulness and importance of clinical psychology. The passage states, however, that both groups practice psychotherapy, which is a form of clinical psychology. Psychoanalysts practice psychoanalysis, and paragraph 7 indicates that humanists such as Carl Rogers have also made distinguished contributions to clinical psychology. Since both Freudian psychoanalysis and humanist approaches such as Rogers's client-centered therapy are forms of clinical psychology, we can conclude that both schools believe in the importance of clinical psychology, though they differ with regard to what they would consider the most effective therapy styles or perspectives. So, choice C is incorrect. As for choice D, we know from the third sentence of paragraph 5 that humanists believe conscious experience to be the one proper subject of study in psychology. It appears that psychoanalysts feel much the same way. The last sentence of paragraph 2 says that psychoanalysts sought to bring repressed memories to patients' conscious awareness. Both types of psychologists are concerned about conscious experience. Choice D would not be the most probable subject of disagreement between psychologists.