Preparing for Civil Service Examination: Reading Comprehension Practice 5

Do you often worry about how to improve your reading comprehension level efficiently? Now, our website has carefully prepared a series of reading comprehension questions closely related to Civil Service Examination, covering a wide range of topics and question types, aiming to hone your reading analysis and comprehension skills in all aspects.

Read the passages and answer the questions that follow. Good luck!

 

Even the smallest quantity of salmonella may, in the future, be easily detected with a technology known as SERS, short for “surfaceenhanced Raman scattering.” U.S. Department of Agriculture (USDA) scientist Bosoon Park at Athens, GA, is leading exploratory studies of this analytical technique’s potential for quick, easy, and reliable detection of salmonella and other foodborne pathogens.

According to the U.S. Centers for Disease Control and Prevention, salmonella causes more than one million cases of illness in the United States every year.

If SERS proves successful for cornering salmonella, the technique might be used at public health laboratories around the nation to rapidly identify this or other pathogens responsible for outbreaks of foodborne illness, according to Park, an agricultural engineer. What’s more, tomorrow’s food makers might use SERS at their in-house quality control labs. The Agricultural Research Service is the USDA’s chief intramural scientific research agency. Park’s research supports the USDA priority of enhancing food safety.

In a SERS analysis, a specimen is placed on a surface, such as a stainless steel plate, that has been “enhanced,” or changed from smooth to rough. For some of their research, Park’s team enhanced the surface of stainless steel plates by coating them with tiny spheres, made up of a biopolymer encapsulated with nanoparticles of silver.

Rough surfaces, and colloidal metals such as silver, can enhance the scattering of light that occurs when a specimen, placed on this nanosubstrate, is scanned with the Raman spectrometer’s laser beam.

The scattered light that comes back to the spectroscope forms a distinct spectral pattern known as a Raman spectral signature, or Raman scattered signal. Researchers expect to prove the concept that all molecules, such as those that make up salmonella, have their own unique Raman spectral signature.

The idea of using a substrate of silver nanoparticles for Raman spectroscopy is not new. But in SERS studies to detect foodborne pathogens, the use of a surface enhanced with biopolymers coated with silver nanoparticles is apparently novel.

In work with comparatively large concentrations of two different kinds, or serotypes, of salmonella enterica—enteritidis and typhimurium—Park’s tests showed, apparently for the first time, that SERS can differentiate these two serotypes. With further research, SERS may prove superior for finding very small quantities of bacteria in a complex, real-world background, such as a food or beverage sample, Park notes.

 

1. Which of the following is NOT like the rest of the answer choices?
a. foodborne pathogens
b. salmonella
c. typhimurium
d. clemteritidis
e. biopolymers

Correct Answer: e

Answer Explanation:

All the other choices are foodborne illnesses or conditions that will lead to a foodborne illness.

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2. Which of the following most accurately expresses the main idea of the passage?
a. Colloidal metals such as silver can enhance the scattering of light that occurs when a specimen is placed under a Raman laser.
b. Scientists are close to finding a way to detect salmonella and other foodborne illnesses with the development of a surfaceenhanced Raman scattering laser.
c. The U.S. Department of Agriculture has been diligently looking for an effective way to detect foodborne illness earlier.
d. The idea of using a substrate of silver nanoparticles is revolutionary and SERS is one way of illustrating that.
e. According to the Centers for Disease Control and Prevention, salmonella causes a great number of health problems that the general public is not aware of.

Correct Answer: b

Answer Explanation:

The passage is about the development and implementation of SERS, how it works, where it will work, and how that will affect tracking foodborne illness. This is clearly the main idea. The facts regarding colloidal metals is a supporting idea of this passage, not the main idea, rendering choice a incorrect. Choices c and d are both supporting ideas as well, so they are both incorrect. There is no evidence to back choice e, so it is incorrect.

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3. According to the passage, a nanosubstrate is
a. a laser beam that can detect salmonella.
b. tiny spheres made of a colloidal metal.
c. an enhanced surface that the specimen being tested will be placed on.
d. the scattered light that comes back to the spectroscope after using SERS.
e. a foodborne pathogen.

Correct Answer: c

Answer Explanation:

The sixth paragraph states that a specimen will be placed on this enhanced surface, a nanosubstrate. According to the passage, a nanosubstrate is not a laser beam, so choice a is incorrect. The surface can be enhanced by tiny spheres of colloidal metal, but that’s not a defining characteristic, making choice b incorrect. A nanosubstrate is not described as the scattering of light, so choice d is incorrect. A nanosubstrate is not a foodborne pathogen, so choice e is incorrect.

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