Free Test Prep MCAT Exam Questions

Which of these is NOT true about ultrasound waves?Section: Physical Sciences 

When electric current passes through an aqueous solution, which of the following ionic migrations is correct?Section: Physical Sciences 

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, longestablished currents, psychoanalysis and behaviorism. The hostility between these two older schools, as wellas 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 mostintrospective. 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 andearly 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 improvementwhen the psychoanalyst eventually unlocks these long-repressed memories of conflict and brings them to thepatient’s conscious awareness.In the heyday of behaviorism, which occurred between the two world wars, the psychoanalytic movement washeavily criticized for being too concerned with inner subjective experience. Behavioral psychologists, dismissingideas and feelings as unscientific, tried to deal only with observable and quantifiable facts. They perceived thehuman being merely as an organism which generated responses to stimuli produced by its body and theenvironment around it. Patients’ neuroses no longer needed analysis; they could instead by modified bybehavioral conditioning. Not even babies were safe: B.F. Skinner devised a container in which infants could beraised 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 Freudianperspective and the mechanistic approach of behaviorism. They questioned the idea that human personalitybecomes permanently fixed in the first few years of life. They wondered if the purpose of psychology was reallyto reduce people to laboratory specimens. Was it not instead possible that human beings are greater than thesum 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 movementcannot 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 propersubject 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 theindividual’s self-image.Abraham Maslow, a pioneer of the Third Stream, articulated a hierarchy of basic human needs, starting withfood, 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 needshave been satisfied. Individuals atop the pyramid, having developed their potential to the highest possibleextent, are said to be “self-actualized”.If this humanist theoretical perspective is aimed at empowering the individual, so too are the movement’sefforts in the practical realm of clinical psychology. Believing that traditional psychotherapists tend to leadpatients toward predetermined resolutions of their problems, Carl Rogers pressed for objective evaluations ofboth 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 theautonomy of the client (i.e., patient). In client-centered therapy, clients choose the subjects for discussion, andare encouraged to create their own solutions to their problems.The author most probably believes that, in its early days, the humanistic psychology movement:I. benefited from dissension among psychologists.II. acknowledged Maslow and Rogers as its only leaders.III. was an offshoot of behaviorism.Section: Verbal Reasoning 

Ink jet printers produce high resolution output, at a lower cost than laser printers, by generating charged inkdroplets which are then deflected onto a sheet of paper by an electric field. Each droplet deflected by the fieldstrikes the paper and forms a tiny dot of ink. While a typical printed letter requires about 100 drops, an ink jetprinter is able to produce drops at a rate of 100,000 per second.The essential elements of the ink jet printer head are shown in Figure 1. The drop generator produces the inkdroplets, each with a mass of approximately 1.2 × 10−10 kg and a diameter of approximately 30 μm. The dropsthen enter a highly precise charging unit which controls the charge q on each droplet to within 2%, with typicalcharges for drops generated by various ink jet printers ranging from −1.0 × 10−13 C to −3.0 × 10−14 C. Thecharged droplets are subsequently passed through the deflecting plates between which a variable electric fieldis generated. The electronically controlled electric field between the plates is typically varied over a range from1.0 × 106 N/C to 5.4 × 106 N/C, and is used to aim the ink droplet at the paper. An ink jet printer deflects a particular ink droplet by 1.5 mm in the region of the deflector. Which of the followingis a possible value of the work done on the droplet?Section: Physical Sciences 

Due to ever-increasing paranoia about the transmission of hepatitis and AIDS via blood transfusions and thefrequent difficulty of procuring matching blood donors for patients, researchers have been working at a feverishpace to produce disease-free and easy-to-use blood substitutes. The difficulty most synthetic blood researcheshave had is in formulating a substance that combines qualities of sterility, high capacity for carrying oxygen tobody tissues, and versatility within the human body. Three major substitute technologies have been developedto date; each has certain advantages and shortcomings.“Red blood,” the first of the blood substitute technologies, is derived from hemoglobin which has been recycledfrom 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 insynthetic blood because of its oxygen-carrying capacity. However, hemoglobin can sometimes constitute a twofold 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 wereexposed in the cell. Second, naked hemoglobin is extremely dangerous to the kidneys, causing blood flow atthese organs to shut down and leading, ultimately, to renal failure. Additional problems arise from the fact thathemoglobin is adapted to operate optimally within the intricate environment of the red blood cell. Stripped of theprotection of the cell, the hemoglobin molecule tends to suffer breakdown within several hours. Althoughmodification has produced more durable hemoglobin molecules which do not cause renal failure, undesiredside 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 calledperfluorocarbons (PFCs). Unlike blood, PFCs are clear oil like liquids, yet they are capable of absorbingquantities of oxygen up to 50% of their volume, enough of an oxygen carrying potential for oxygen-dependentorganisms to survive submerged in the liquid for hours by “breathing” it. Although PFCs imitate real blood byeffectively absorbing oxygen, scientists are primarily interested in them as constituents of blood substitutesbecause they are inherently safer to use than hemoglobin-based substitutes. PFCs do not interact with anychemicals in the body and can be manufactured in near-perfect sterility. The primary pitfall of PFCs is in theirtendency to form globules in plasma that can block circulation. Dissolving PFCs in solution can mitigateglobulation; 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 modifiedversion of human hemoglobin by genetically-altered bacteria. Fortunately, this synthetic hemoglobin seems toclosely mimic the qualities of sterility, and durability outside the cellular environment, and the oxygen-carryingefficiency of blood. Furthermore, researchers have found that if modified hemoglobin genes are added tobacterial DNA, the bacteria will produce the desired product in copious quantities. This procedure is extremelychallenging, 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 bloodsubstitute continues. Scientists hope that in the near future safe synthetic blood transfusions may ease bloodshortages 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 byall of the following EXCEPT:Section: Verbal Reasoning