Dogs are widely employed by the police as biological detection systems

Dogs are widely employed by the police as biological detection systems to detect the smuggling and storage of drugs. Yet, recent evidence suggests that insects, rather than mammals, may be used more effectively in this capacity. One of the disadvantages of dogs lies in the fact that these animals, like humans, may get bored and lose interest. Other problems may also result from the emotional relationship between a dog and its owner. Insects, on the other hand, remain relatively free of these emotional attachments and, at the same time, possess biological detection mechanisms that are at least as effective as those of mammals.

Insects have olfactory systems that are very similar to those of vertebrates, detecting odors via finger-like protuberances on the antenna, called olfactory sensilla. The odorant molecule passes through pores in the outer cuticle of the sensillum and becomes attached to an odorant binding protein. This protein carries the hydrophobic ligand through the lymph fluid found inside the cell and attaches it to a receptor on the dendritic projections of a sensory nerve cell. Finally, this receptor sends a signal to the central nervous system, allowing for easy detection by researchers. The position of the insect olfactory organs on the surface of its body allows for direct investigation of the system’s response. A technique developed by German biologist Dietrich Schneider in the 1950s became the first method that enabled researchers to record the activity in insect olfactory nerves and identify the compounds that trigger a behavioral response. The recent developments in this direction suggest that the detection mechanisms of insects are likely to be applied in practice in the near future.

1. Which of the following statements can be most reasonably inferred from the passage above?

(A) Some police departments have already tested using insects to detect smuggling.
(B) The use of dogs to detect smuggling dates back to the nineteenth century.
(C) Detection of signals sent by the receptors to the central nervous system is easier in insects than in mammals.
(D) In the first half of the twentieth century, there was no reliable method for recording the activity in insect olfactory nerves and identifying the compounds that trigger a behavioral response.
(E) The position of the insect olfactory organs on its body varies between flying insects and crawling insects.



2. Which of the following most accurately describes the primary purpose of the passage?

(A) To advocate a wider use for the biological detection mechanisms of dogs and other mammals.
(B) To describe possible disadvantages involved in the use of dogs’ biological detection mechanisms.
(C) To describe biological detection mechanisms of insects and suggest that they may provide a viable alternative to those of mammals.
(D) To discuss the process used by insects to detect odors.
(E) To discuss the methods used by biologists to explore insects’ olfactory organs.



3. It can be inferred from the passage that dogs could be used more effectively in detecting drugs if which of the following were true?

(A) They could last without food for longer periods of time.
(B) They could visually recognize the drugs they are supposed to detect.
(C) They could not only smell but also taste the drugs they are asked to detect.
(D) They could use finger-like protuberances for detecting odors.
(E) They could not develop emotional relationships with people.



4. Which of the following best describes the author’s attitude towards the prospects of using insects’ biological detection systems in practice?

(A) Moderately optimistic
(B) Completely neutral
(C) Highly doubtful
(D) Largely uninterested
(E) Mildly pessimistic



5. According to the passage, which of the following roles is played by an odorant binding protein?

(A) It sends a signal to the central nervous system.
(B) It carries the hydrophobic ligand through the lymph fluid and attaches it to a receptor.
(C) It passes through pores in the outer cuticle of the sensillum.
(D) It picks up the signal from the olfactory sensilla.
(E) It transmits odors via finger-like protuberances on the antenna.



6. It can be inferred from the passage that insects would be less useful for helping researchers to detect drugs if which of the following were true?

(A) They were as accurate as, but not more accurate than, dogs in detecting drugs.
(B) Insect olfactory systems did not deliver odorants to nerve cells in the same way as vertebrate olfactory systems do.
(C) Dietrich Schneider did not develop the first method that enabled researchers to record the activity in insect olfactory nerves.
(D) They did not have finger-like protuberances for detecting odors.
(E) The signal sent to the insect’s central nervous system did not allow researchers to classify the compound that triggered the response.



Q. 7 According to the passage, researchers are able to capture and investigate an insect’s response to a certain odor because

A) Researchers have trained insects to respond to different stimuli in different ways
B) Insects can be used more effectively than dogs to detect certain odors
C) Insect olfactory systems are similar to vertebrate olfactory systems
D) The finger-like protuberances on insect antennae are rich in odorant-binding proteins
E) Insect olfactory organs are located on the surface of an insect’s body