Question 1

At a recent meeting of the American Public Transit Association, the Environmental Protection Agency unveiled

stringent new standards for pollution control. The transit authorities were particularly concerned about the

implementation of a proposed “Clean Air Act.” They believed the provisions of the Clean Air Act could severely

affect basic services to their local communities. Many transit agencies were concerned that it would be difficult

to comply with the pollution and emissions control standards while continuing to operate within realistic budgets.

The aim of the Clean Air Act is to assure that by the year 2000, there will be a reduction of at least 10 million

tons of sulfur dioxide from 1980 levels. The bill also calls for a reduction in pollutants that contribute to the

depletion of ozone. Strict regulations of toxic air emissions would have to be established and enforced.

Additionally, the Clean Air Act would establish specific acid-rain reduction quotas and enforce severe penalties

for transgressors of any of the new clean air regulations.

There is little doubt that mass-transit suppliers will be considerably affected by this new legislation, just as the

chemical and petroleum industries have already been affected by similar legislation. Transit authorities are

challenged to strike a difficult balance between complying with the government’s new standards and developing

an official concern for the environment, while continuing to fulfill the transportation needs of the general

population.

Among the areas addressed by the Clean Air Act, the topic of mobile resources is of particular interest to mass

transit authorities. Provisions contained in the Act under this title are aimed at encouraging the development

and practical use of alternative fuel sources, like solar energy and methane fuel. The goal of this section of the

Act is to eradicate toxic fuel emissions in order to provide cleaner air and a more favorable environment. The

Act even goes so far as to declare that in cities like New York, Los Angeles and Houston – where air quality is

particularly noxious and toxins exceed the limits of federal regulations – forms of mass transit should run on socalled “clean-burning fuels” by the year 2000. Such fuels include reformulated gasoline, propane, electricity,

natural gas, ethanol, methanol, or any similar type of low-emission fuel. In addition, the Act proposes that, by

1994, all new urban buses in cities with populations exceeding one million must operate solely on clean-burning

fuels.

The topics of alternative fuels and alternative fuel vehicles represent, by far, the most controversial issue in the

Clean Air Act. President Bush has called alternative fuels “bold and innovative” means to control pollution, but

according to many transportation experts, the Act’s proposals on alternative fuel usage are unrealistic. The

transit authorities recognize that concern for the environment and health hazards like pollution are global

issues. However, most transit officials concur that inventing and developing new ways to fuel mass transit will

take at least 50 years to realize. They point out that the Act does not mention the political and social

ramifications of usurping the role of the petroleum industries. The Act does not mention if or how the thousands

of people employed by the oil industry will get retrained to produce and implement the use of “clean” fuel.

No one disputes the fact that people need some form of transportation to get from place to place. Preserving

the environment should be a priority, yet we need to remember that even if toxic emissions are completely

eliminated sometime in the future, the challenge of moving mass numbers of people where they want to go will

still exist and must remain a priority. Transit authorities contend that unless the Clean Air Act also

acknowledges this, and develops a way to encourage mass transit over personal transportation, the problems

of pollution might not be significantly altered. They suggest that there are many areas in this country that have

little or no mass transit and that, if the Clean Air Act’s goal is to reduce pollution, perhaps the most practical and

realistic means to achieve that goal is to encourage the development and maintenance of mass transit

systems.

The main goal of the “Mobile Resources” section of the Clean Air Act is to:

Section: Verbal Reasoning

Options :

A : reduce toxic vehicle emissions for cleaner air and a better environment.

B :

encourage the development and practical use of different forms of mass transportation.

C :

convince the general public of the environmental benefits of mass transit over private transportation.

D : force private oil industries to redevelop their methods of production so there is less pollution.

Answer: A

Question 2

…Until last year many people – but not most economists – thought that the economic data told a simple tale.

On one side, productivity – the average output of an average worker – was rising. And although the rate of

productivity increase was very slow during the 1970’s and early 1980’s, the official numbers said that it had

accelerated significantly in the 1990’s. By 1994 an average worker was producing about 20 percent more than

his or her counterpart in 1978.

On the other hand, other statistics said that real, inflation- adjusted wages had not been rising at anything like

the same rate. In fact, some of the most commonly cited numbers showed real wages actually falling over the

last 25 years. Those who did their homework knew that the gloomiest numbers overstated the case…Still, even

the most optimistic measure, the total hourly compensation of the average worker, rose only 3 percent between

1978 and 1994…

…But now the experts are telling us that the whole thing may have been a figment of our statistical

imaginations… a blue-ribbon panel of economists headed by Michael Boskin of Stanford declared that the

Consumer Price Index [C.P.I.] had been systematically overstating inflation, probably by more than 1 percent

per year for the last two decades, mainly failing to take account of changes in the patterns of consumption and

improvements in product quality…

…The Boskin report, in particular, is not an official document – it will be quite a while before the Government

actually issues a revised C.P.I., and the eventual revision may be smaller than Boskin and his colleagues

propose. Still, the general outline of the resolution is pretty clear. When all the revisions are taken into account,

productivity growth will probably look somewhat higher than it did before, because some of the revisions being

proposed to the way we measure consumer prices will also affect the way we calculate growth. But the rate of

growth of real wages will look much higher – and so it will now be roughly in line with productivity, which will

therefore reconcile numbers on productivity and wages with data that show a roughly unchanged distribution of

income between capital and labor. In other words, the whole story about workers not sharing in productivity

gains will turn out to have been based on a statistical illusion.

It is important not to go overboard on this point. There are real problems in America, and our previous concerns

were by no means pure hypochondria. For one thing, it remains true that the rate of economic progress over

the past 25 years has been much slower than it was in the previous 25. Even if Boskin’s numbers are right, the

income of the median family – which officially has experienced virtually no gain since 1973 – has risen by only

about 35 percent over the past 25 years, compared with 100 percent over the previous 25. Furthermore, it is

quite likely that if we “Boskinized” the old data – that is, if we tried to adjust the C.P.I. for the 50’s and 60’s to

take account of changing consumption patterns and rising product quality – we would find that official numbers

understated the rate of progress just as much if not more than they did in recent decades…

…Moreover, while workers as a group have shared fully in national productivity gains, they have not done so

equally. The overwhelming evidence of a huge increase in income inequality in America has nothing to do with

price indexes and is therefore unaffected by recent statistical revelations. It is still true that families in the

bottom fifth, who had 5.4 percent of total income in 1970, had only 4.2 percent in 1994; and that over the same

period the share of the top 5 percent went from 15.6 to 20.1. And it is still true that corporate C.E.O.’s, who

used to make about 35 times as much as their employees, now make 120 times as much or more…

…While these are real and serious problems, however, one thing is now clear: the truth about what is

happening in America is more subtle than the simplistic morality play about greedy capitalists and oppressed

workers that so many would-be sophisticates accepted only a few months ago. There was little excuse for

buying into that simplistic view then; there is no excuse now…

The Boskin report does all of the following EXCEPT:

Section: Verbal Reasoning

Options :

A :

Reveals that the C.P.I. was inaccurate.

B :

Reconciles the present disparity between productivity levels, wage levels, and the percentage of labor’s

share in national income.

C : Reveals the reasons for the increasing disparity between the highest and lowest income earners.

D :

Helps clarify economic progress in the 1950s and 1960s.

Answer: C

Question 3

Several techniques have been developed to determine the order of a reaction. The rate of a reaction cannot be

predicted on the basis of the overall equation, but can be predicted on the basis of the rate-determining step.

For instance, the following reaction can be broken down into three steps.

A + D → F + G

Step 1

A → B + C

(slow)

Step 2

B + D → E + F

(fast)

Step 3

E + C → G

(fast)

Reaction 1

In this case, the first step in the reaction pathway is the rate-determining step. Therefore, the overall rate of the

reaction must equal the rate of the first step, k1 [A] where k1 is the rate constant for the first step. (Rate

constants of the different steps are denoted by kx

, where x is the step number.)

In some cases, it is desirable to measure the rate of a reaction in relation to only one species. In a secondorder reaction, for instance, a large excess of one species is included in the reaction vessel. Since a relatively

small amount of this large concentration is reacted, we assume that the concentration essentially remains

unchanged. Such a reaction is called a pseudo first-order reaction. A new rate constant, k', is established, equal

to the product of the rate constant of the original reaction, k, and the concentration of the species in excess.

This approach is often used to analyze enzyme activity.

In some cases, the reaction rate may be dependent on the concentration of a short-lived intermediate. This can

happen if the rate-determining step is not the first step. In this case, the concentration of the intermediate must

be derived from the equilibrium constant of the preceding step. For redox reactions, the equilibrium can be

correlated with the voltage produced by two half-cells by means of the Nernst equation. This equation states

that at any given moment:

Equation 1

When

a A + b B → c C + d D

Reaction 2

Note: R = 8.314 J/K·mol; F = 9.6485 × 104 C/mol.)

Catalysts are effective in increasing the rate of a reaction because they:

Section: Physical Sciences

Options :

A : increase the energy of the activated complex

B :

increase the value of the equilibrium constant.

C :

decrease the number of collisions between reactant molecules.

D : lower the activation energy

Answer: D

Question 4

In an acetyl molecule, two atoms of carbon are bonded by:

Section: Physical Sciences

Options :

A : two sigma bonds and two pi (π) bond.

B : one sigma bond and one pi (π) bond.

C :

two sigma bonds and one pi (π) bond.

D :

one sigma bonds and two pi (π) bond.

Answer: D

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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