Question 1

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 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.

According to the passage, the ultimate goal of Carl Rogers’s client-centered therapy is:

Section: Verbal Reasoning

Options :

A :

simplification of the Third Stream’s theoretical perspective.

B :

self-directed personal growth for the client.

C :

rejection of Maslow’s scheme of self-actualization.

D :

increased autonomy of psychotherapists.

Answer: B

Question 2

Although we know more about so-called Neanderthal men than about any other early population, their exact

relation to present-day human beings remains unclear. Long considered sub-human, Neanderthals are now

known to have been fully human. They walked erect, used fire, and made a variety of tools. They lived partly in

the open and partly in caves. The Neanderthals are even thought to have been the first humans to bury their

dead, a practice which has been interpreted as demonstrating the capacity for religious and abstract thought.

The first monograph on Neanderthal anatomy, published by Marcelling Boule in 1913, presented a somewhat

misleading picture. Boule took the Neanderthals’ lowvaulted cranium and prominent brow ridges, their heavy

musculature, and the apparent overdevelopment of certain joints as evidence of a prehuman physical

appearance. In postulating for the Neanderthal such “primitive” characteristics as a stooping, bent-kneed

posture, a rolling gait, and a forward-hanging head, Boule was a victim of the rudimentary state of anatomical

science. Modern anthropologists recognize the Neanderthal bone structure as that of a creature whose bodily

orientation and capacities were very similar to those of present-day human beings. The differences in the size

and shape of the limbs, shoulder blades, and other body parts are simply adaptations which were necessary to

handle the Neanderthal’s far more massive musculature. Current taxonomy considers the Neanderthals to have

been fully human and thus designates them not as a separate species, Homo neanderthalensis, but as a

subspecies of Homo sapiens: Homo sapiens neanderthalensis.

The rise of the Neanderthals occurred over some 100,000 years – a sufficient period to account for evolution of

the specifically Neanderthal characteristics through free interbreeding over a broad geographical range. Fossil

evidence suggests that the Neanderthals inhabited a vast area from Europe through the Middle East and into

Central Asia from approximately 100,000 years ago until 35,000 years ago. Then, within a brief period of five to

ten thousand years, they disappeared. Modern human, not found in Europe prior to about 33,000 years ago,

thenceforth became the sole inhabitants of the region. Anthropologists do not believe that the Neanderthals

evolved into modern human beings. Despite the similarities between Neanderthal and modern human anatomy,

the differences are great enough that, among a population as broad-ranging as the Neanderthals, such an

evolution could not have taken place in a period of only ten thousand years. Furthermore, no fossils of types

intermediate between Neanderthals and moderns have been found.

A major alternative hypothesis, advanced by E. Trinkaus and W.W. Howells, is that of localized evolution.

Within a geographically concentrated population, free interbreeding could have produced far more pronounced

genetic effects within a shorter time. Thus modern human could have evolved relatively quickly, either from

Neanderthals or from some other ancestral type, in isolation from the main Neanderthal population. These

humans may have migrated throughout the Neanderthal areas, where they displaced or absorbed the original

inhabitants. One hypothesis suggests that these “modern” humans immigrated to Europe from the Middle East.

No satisfactory explanation of why modern human beings replaced the Neanderthals has yet been found. Some

have speculated that the modern humans wiped out the Neanderthals in warfare; however, there exists no

archeological evidence of a hostile encounter. It has also been suggested that the Neanderthals failed to adapt

to the onset of the last Ice Age; yet their thick bodies should have been heat-conserving and thus well-adapted

to extreme cold. Finally, it is possible that the improved tools and hunting implements of the late Neanderthal

period made the powerful Neanderthal physique less of an advantage than it had been previously. At the same

time, the Neanderthals’ need for a heavy diet to sustain this physique put them at a disadvantage compared to

the less massive moderns. If this was the case, then it was improvements in human culture – including some

introduced by the Neanderthals themselves – that made the Neanderthal obsolete.

All of the following are hypotheses about the disappearance of the Neanderthals EXCEPT:

Section: Verbal Reasoning

Options :

A : the Neanderthal physique became a handicap instead of an advantage.

B :

the Neanderthals failed to adapt to climatic changes.

C :

the Neanderthals evolved into modern humans.

D : modern humans exterminated the Neanderthals.

Answer: C

Question 3

An automatic external defibrillator (AED) is simply a series of capacitors used to store a very large charge,

which is then discharged through the patient’s chest in a short time. If the capacitor in an AED is fully charged

and the AED is no longer connected to the power source, what will happen to the energy stored in the AED if

the dielectric (k = 1.5) is removed?

Options :

A : increase by a factor of 1.5

B :

increase by a factor of 2.25

C :

decrease by a factor of 1.5

D : decrease by a factor of v1.5

Answer: A

Question 4

It is critical for the human body blood to maintain its pH at approximately 7.4. Decreased or increased blood pH

are called acidosis and alkalosis respectively; both are serious metabolic problems that can cause death. The

table below lists the major buffers found in the blood and/or kidneys.

Table 1

Buffer

pKa of a typical conjugate acid:* MCAT-part-3-page300-image127

Histidine side chains

Organic phosphates

N-terminal amino groups

6.1

6.3

6.8

7.0

8.0

9.2

*For buffers in many of these categories, there is a range of actual pKa values.

The relationship between blood pH and the pKa of any buffer can be described by the Henderson-Hasselbalch

equation:

pH = pKa + log([conjugate base] / [conjugate acid])

Equation 1

Bicarbonate, the most important buffer in the plasma, enters the blood in the form of carbon dioxide, a

byproduct of metabolism, and leaves in two forms: exhaled CO2 and excreted bicarbonate. Blood pH can be

adjusted rapidly by changes in the rate of CO2 exhalation. The reaction given below, which is catalyzed by

carbonic anhydrase in the erythrocytes, describes how bicarbonate and CO2 interact in the blood.

Reaction 1

What would be the order of conjugate acid strength in the following buffers?

Section: Physical Sciences

Options :

A :

Histidine side chains = organic phosphates > NH4

+

B :

NH4

+ > organic phosphates > histidine side chains

C :

Histidine side chains > organic phosphates > NH4

+

D :

NH4

+ > organic phosphates = histidine side chains

Answer: C

Question 5

Nitric oxide, NO, has recently been found to have widespread physiological effects, acting as a major regulator

in the nervous, cardiovascular, and immune systems. The production of NO in the body is regulated by specific

NOS enzymes which exist in at least three different isoforms – bNOS, eNOS, and macNOS. Each of these

isoforms differ in location and function and serve to mediate different physiological responses to NO. Some

physiological roles of NO have been demonstrated as follows:

I. In the central nervous system, NO production is regulated by bNOS. Calcium ion concentrations of 200-400

nM in the central nervous system activate bNOS to catalyze the formation of NO. NO exerts definite effects on

brain function although its specific roles are not well established. bNOS inhibitors have been found to block the

release of neurotransmitter from presynaptic neurons. Excess levels of NO are also thought to contribute to

neurodegenerative disorders such as Alzheimer’s disease.

II. In the blood vessels, NO is produced by eNOS which is activated by Ca2+ concentrations of 200-400 nM. NO

acts as the major endogenous vasodilator in blood vessels. It diffuses into smooth muscle cells and leads to

muscle relaxation by stimulating cGMP formation through activation of guanylyl cyclase. In addition, NO

regulates the vascular system by inhibiting platelet aggregation and adhesion.

III. The role of NO in the immune system is regulated by macNOS through a pathway that is not Ca2+

dependent. Rather, exposure to cytokines, including interleukin-1 and interferon- γ, leads to synthesis of large

amounts of NO by activation of macNOS in response to inflammatory stimuli. The NO produced plays a

definitive role in the mediation of the activities of macrophages and neutrophils. NO also acts to inhibit the

mechanism of viral replication.

A “knock out” mouse with a mutant bNOS protein was generated by recombination techniques. The mutant

protein was identical to the wild-type protein except for the identity of amino acid 675; the mutated bNOS has

Tryptophan instead of Cysteine at position 675. Which of the following is responsible for the mutant protein?

Section: Biological Sciences

Options :

A :

Frame shift mutation

B :

Single base-pair deletion

C : Point mutation

D : Nonsense mutation

Answer: C

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