Medical Tests MCAT-TEST Online Practice Questions and Exam Preparation

Medical Tests MCAT-TEST Online Questions & Answers

• Question 341:

  The process by which individuals decide and choose to seek assistance for health or mental health problems is called help-seeking. Table 1 displays the percentage of American Indian/Alaska Native and non-Hispanic White adults who received mental health or counseling treatment in 2008

  Help-seeking is a complex process and individuals will choose to obtain treatment for a variety of reasons. One of the strongest individual-related help-seeking predictors amounts to perceiving the need to do so. Other individual-related factors are the educational and the socioeconomic status. There may also be systematic factors that prevent people from doing so, such as general mistrust of health, mental health, and social service institutions, particularly among racial and ethnic minorities. It has been speculated that some of the mistrust stems from research studies, sponsored by medical establishments, where racial and ethnic minorities express concerns of being recruited for the purpose of serving as guinea pigs. Focus groups with African Americans and Chinese immigrants confirmed this anxiety and fear.

  Thus, cultural factors also play a role in the help-seeking process. Western cultural norms about medicine are premised on norms of individualism. However, individuals from other cultures and racial and ethnic minority groups tend to be both more collectivistic and fatalist. Disease, both medical and mental, is believed to occur because of fate. It is not something where one should spend much time and effort fighting; the needs of the family and even of the extended family are to come first.

  Table 1 Access to health care: Percentage of adults who received mental health treatment or counseling in the past year, 2008

  

  Source: Adapted from U.S. Department of Health and Human Services,"Mental Health and American Indians/ Alaska Natives"

  What would the main focus of supporters of a medicalized approach to mental health be?

  A. They would disregard mental health as a myth, and mainly inquire about and treat clients' physical symptoms through the use of prescription drugs.
  B. They would mainly focus on establishing a strong, healthy relationship with clients, and attempt to build up their psychological strengths.
  C. They would insist that mental illness should be viewed in a holistic manner and employ complementary alternative medicines as a first avenue of intervention.
  D. Just like with any other physical disease, they would inquire about existing symptoms, formulate a diagnosis, and attempt to treat or cure the diagnosed disease.
  D. Just like with any other physical disease, they would inquire about existing symptoms, formulate a diagnosis, and attempt to treat or cure the diagnosed disease.

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  Explanation/Reference:

  D is correct. Those who support a medicalized approach to mental health approach these illnesses in the same way they approach medical and physical diseases. Symptoms are listed, a diagnosis is put forward, and adequate treatments for such diagnosis ensued. These treatments usually, but not necessarily involve the use of prescription drugs or surgery. It has been widely criticized for issues such as being extremely positivist; disregarding the strengths or healthy aspects of individuals; and dehumanizing, de- contextualizing and reducing the person to a disease. Every psychosocial aspect may be "pathologized", that is, regarded as a medical problem that urgently needs to be corrected, removed, cured, changed, or treated.

  A. This is incorrect. Thomas Szasz is known for advocating that mental illness is a myth - though not necessarily insisting on treating exclusively physical symptoms through the use of drugs. Unlike wise, those who support the medicalization of mental health do not necessarily claim it is a myth. B. This is incorrect. Positive psychology and more humanistic clinical psychology trends would address mental health issues by emphasizing relational aspects and psychological strengths. They would stand against the medicalization of mental health.

  C. This is incorrect. Complementary Alternative Medicine (CAM) and holistic treatments are not advocated by those who support the medicalization of mental health.

• Question 342:

  In nerve cells, microtubule-associated proteins (MAPs), most notably MAP2 and MAP tau, act to stabilize microtubules. In a mouse model, a mutant is developed that vastly reduced function across all families of MAPs, leading to increased microtubule degradation. Which cellular activity would likely be most affected?

  A. Cardiac muscle contraction
  B. Transcription of mRNA from DNA
  C. Krebs cycle
  D. Meiosis
  D. Meiosis

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  Explanation/Reference:

  Microtubules are a component of the cytoskeleton and central to a number of cellular processes that involve movement, such as mitosis and meiosis. They provide the framework for the organization and separation of chromosomes and sister chromatids during that process. Thus (D) is the correct answer.

  A: The movement created by muscle cells depends on actin and myosin, rather than microtubules.

  B: Transcription is primarily regulated by enzymes, not microtubules.

  C: The Krebs cycle depends primarily on mitochondria, not microtubules.

• Question 343:

  Fireworks have been used for centuries in celebrations around the world. One of the primary components of these devices, black powder, was developed by the Chinese over a thousand years ago and is still used today as a propellant and explosive. Black powder is composed of potassium nitrate (KNO3), charcoal (primarily C) and sulfur (S8) in a 75:15:10 ratio by weight. It is very stable if kept dry but can easily be ignited by a spark or burning fuse to undergo the following reaction:

  

  Reaction 1 The basic firework is shown in Figure 1. Fireworks rely on a particular kind of combustion in which oxygen is supplied by oxidizing agents included in the pyrotechnic mixture. When ignited, the solid propellant begins to liquefy and vaporize allowing the fuel and oxidizing agents to interact more intimately leading to rapid expansion of gases. Delay fuses time the ignition of the other compartments to occur when the shell is high above ground.

  

  Figure 1

  The light generating units of the firework are called stars and are dispersed and ignited by the bursting charge in each compartment. The intense colors of modern fireworks are generated by molecular emitters. For example, barium chloride emits green light (510?30 nm) and strontium chloride emits vibrant red light (605?50 nm). Many of the molecular emitters are unstable at room temperature and so cannot be placed directly into the firework. Instead, they are synthesized in the flame of the pyrotechnic reaction and exist for a short time before decomposing. The flame temperature must be carefully adjusted so that these emitters do not decompose too rapidly.

  

  Which of the following chemicals is oxidized in the pyrotechnic reaction of gunpowder (Reaction 1)?

  

  A. Option A
  B. Option B
  C. Option C
  D. Option D
  B. Option B

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  Explanation/Reference:

  Carbon is oxidized from 0 to the +4 state in carbon dioxide. Both N and S are reduced in the reaction, as shown below:

  

• Question 344:

  Which of the following species exists as a resonance hybrid?

  

  A. Option A
  B. Option B
  C. Option C
  D. Option D
  C. Option C

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  Explanation/Reference:

  A resonance hybrid is a molecule that cannot be represented by just one Lewis structure; the molecule is said to be a composite of the possible structures. Choice A is wrong because all the atoms have a complete octet--hydrogen having its two electrons--and only one Lewis structure is possible:

  

  Choice B is wrong because it too has only one structure:

  

  Choice C is correct because it does exist as a resonance hybrid:

  

  Keep in mind that the nitrite ion does not exist as one or the other of the above resonance structures but is a composite of them, having a structure somewhere in-between the two. Choice D is wrong because it has only one Lewis structure as well:

  

• Question 345:

  A police officer carries out hundreds of traffic stops every year. When his supervisor is reviewing the officer's records for the past year, he notices that the officer is equally likely to stop people of various genders, ages, and races. However, he is significantly more likely to write tickets for middle-aged white males with dark hair and eyes. When confronted with this fact, the officer truthfully states that he has no idea why that is, and that it must simply be a coincidence. Unbeknownst to the officer, this behavior is tied to the fact that these men look like his father, with whom he had an abusive relationship as a child. What psychological framework would directly address the unconscious bias in his behavior?

  A. Behaviorist
  B. Psychoanalytic
  C. Cognitive behavioral
  D. Humanistic
  B. Psychoanalytic

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  Explanation/Reference:

  Freud's psychoanalytic framework deals with the interactions between the conscious and unconscious mind. Through talk therapy, free association, dream analysis, etc. patients are helped to see how their early childhood experiences shape their unconscious mind and how that then affects their adult lives. Thus choice B, psychoanalytic framework, would directly address this unconscious component of the officer's behavior.

• Question 346:

  NaHCO3 decomposes on heating. In an experiment, a 5 mol sample of NaHCO3 was heated. What volume of CO2 will be yielded in the result of this experiment? Reaction is given as follows:

  2NaHCO3 H2O + CO2

  A. 24 dm3
  B. 60 dm3
  C. 35 dm3
  D. 48 dm3
  B. 60 dm3

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  Explanation/Reference:

• Question 347:

  Electromagnetic radiation from space constantly bombards the earth. Most wavelengths are absorbed by the atmosphere; however, there are two "windows" of nonabsorption through which significant amounts of radiation reach the ground. The first transmits ultraviolet and visible light, as well as infrared light or heat; the second transmits radio waves. As a result, terrestrial organisms have evolved a number of pigments that interact with light in various ways: some capture light energy, some provide protection from light- induced damage, and some serve camouflage or signaling purposes.

  Among these compounds are many conjugated polyenes, which play important roles as photoreceptors. For every chemical compound, there are certain wavelengths of light whose quanta possess exactly the correct amount of energy to raise electrons from their ground state to higher-energy orbitals. For most organic compounds, these wavelengths are in the UV range. However, conjugated double bond systems stabilize the electrons, so that they can be excited by lower-frequency photons with wavelengths in the visible spectrum. Such a pigment, known as a chromophore, will then transmit the "subtraction color," a color complementary to the one absorbed. For instance, carotene, a hydrocarbon compound with eleven conjugated double bonds, absorbs blue light and transmits orange. The wavelength that is absorbed generally increases with the number of conjugated bonds; rings and side-chains also affect wavelength.

  Wavelength Color Subtraction Color 480 nm blue orange 580 nm yellow violet 680 nm red green

  Among the many biological molecules that are affected by light is DNA, the genetic material of living organisms. DNA absorbs ultraviolet light, and may be damaged by UVC (< 280 nm) and UVB (280-315 nm). UVA (315-400 nm) and visible light can actually repair light-induced damage to DNA by a process called photorepair. For this reason, UVA, which also stimulates tanning, was once considered beneficial. However, there is now increasing evidence that UVA can damage skin.

  Many crustaceans produce a blue or green caroteneprotein complex. What is the most likely cause of the color change from green to orange when a lobster is boiled?

  A. Heat causes the prosthetic group to become partially hydrated.
  B. The increase in temperature permits the prosthetic group to absorb shorter wavelengths.
  C. The protein is separated from the carotenoid pigment.
  D. Heat causes the prosthetic group to become oxidized.
  C. The protein is separated from the carotenoid pigment.

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  Explanation/Reference:

  The green color comes from absorption of light by the entire carotene-protein complex; as you know from the passage, the carotene by itself is orange. The fact that boiled lobsters are red and not orange is due to other pigments that are also present. Anyway, when a lobster is cooked, the heat disrupts the intermolecular attractions that attach the carotene molecule, the protein's prosthetic group, to the protein itself. This change in the molecule causes the wavelength of light absorbed to change as well. As a matter of fact, it reduces the number of conjugated double bonds and therefore shortens the wavelength of light absorbed. The red color of the cooked lobster is the transmission color of the isolated carotenoid, with the conjugated bonds from the protein removed. Choices A and D are wrong because if carotene were hydrated or oxidized, it would break the chain of conjugation completely and produce a colorless compound. An increase in temperature, choice B, is only a physical change and won't change the absorption wavelength.

• Question 348:

  A young adult man begins seeing a therapist and tells the therapist that he has homosexual feelings, and that he self-identifies as gay. He is plagued by feelings of worthlessness and fears that he will be subject to what his religion terms "eternal damnation". He feels alienated from his family and friends, as he knows of no other homosexuals in his peer group or family. In the course of working with the man, the therapist helps him see that his feelings are exceptionally common among people who have recently discovered their same-sex feelings, and encourages him to attend a support group for newly "out" gay men. The therapist's approach demonstrates which of the following phenomena?

  A. Stereotype threat
  B. Groupthink
  C. Universalization
  D. Spatial discrimination
  C. Universalization

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  Explanation/Reference:

  Universalization is a form of supportive intervention in which the client is made to understand that others share similar feelings and experiences. This process helps the client see that his feelings are normal, and this normalization process helps reduce distress. That is what the therapist has done for his client in the scenario presented.

  A: Stereotype threat refers to a phenomenon whereby those aware of a stereotype will alter their own behavior due to anxiety about living up to (or down to) the stereotype. It has most sharply been demonstrated in decreased performance on cognitive tasks by minorities, when those minorities are told in advance of the task that the task is an intelligence test.

  B: Groupthink is when a group's decision making process is hampered by an excessive focus on group cohesion and conformity, to the point of excluding any new data that might challenge the group's worldview.

  D: Spatial discrimination occurs when one group is subjected to different treatment based on geography. For example, if a new toxic waste dump is to be located in an area only occupied by disadvantaged minorities, then they are being subjected to a form of spatial discrimination.

• Question 349:

  Compounds containing a hydroxyl group attached to a benzene ring are called phenols. Derivatives of phenols, such as naphthols and phenanthrols, have chemical properties similar to those of phenols, as do most of the many naturally-occurring substituted phenols. Like other alcohols, phenols have higher boiling points than hydrocarbons of similar molecular weight. Like carboxylic acids, phenols are more acidic than their alcohol counterparts. Phenols undergo a number of different reactions; both their hydroxyl groups and their benzene rings are highly reactive. A number of chemical tests can be used to distinguish phenols from alcohols and carboxylic acids.

  

  Thymol, a naturally occurring phenol, is an effective disinfectant that is obtained from thyme oil. Thymol can also be synthesized from m-cresol, as shown in Reaction A below. Thymol can then be converted to menthol, another naturally-occurring organic compound; this conversion is shown in Reaction B.

  Reaction A

  

  Reaction B

  

  The reaction of phenol with dilute nitric acid produces which of the following compounds?

  

  A. Option A
  B. Option B
  C. Option C
  D. Option D
  A. Option A

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  Explanation/Reference:

  To answer this question, you need to know that hydroxyl groups are electron-donating and so they activate aromatic rings towards electrophilic aromatic substitution. Like all electrondonating groups, hydroxyl groups are ortho-para directors. So in this case, the nitro group will add to phenol to form two products, ortho-nitrophenol and para-nitrophenol. This means choice A is the correct answer. Choice B, which has only para-nitrophenol, is incomplete and therefore wrong. Choices C and D can be eliminated because they both include meta-nitrophenol, which will NOT be formed. The only way to get meta-nitrophenol would be to start with nitrobenzene and turn it into a phenol, which would work because the nitro group is an electron-withdrawing, deactivating meta director. The reaction will produce only negligible amounts of meta-nitrophenol, if any.

• Question 350:

  A researcher investigated the equilibrium between CO2, C, and CO as a function of temperature. The equation is given below:

  

  CO2(g) + C(s) 2 CO(g) Carbon dioxide, at 298 K and 1 atm, and an excess of powdered carbon were introduced into a furnace, which was then sealed so that pressure would increase as the temperature rose. The furnace was heated to, and held constant at, a predetermined temperature. The pressure within the furnace chamber was recorded after it had remained unchanged for one hour. The table below shows the pressures recorded for a series of temperatures together with the pressures expected if no reaction had taken place. Table 1

  

  How many pi bonds are in the carbon dioxide molecule?

  B. 1
  C. 2
  D. 3
  C. 2

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  Explanation/Reference:

  The carbon dioxide molecule has a central carbon bonded to two oxygen atoms: carbon shares two electrons with each oxygen, and each oxygen shares two electrons with carbon. As a result of this sharing pattern, two double bonds are formed. You should know that a double bond consists of one sigma bond and one pi bond. Since there are two double bonds, there are two pi bonds, making choice C the correct choice.