Until about five years ago, the very idea that peptide hormones might

Explanation

Inferences 1st paragraph:

Until 5 years ago, researchers believed that peptide hormone was produced in hypothalamus and they found it surprisingly impressive. The reason they found it impressive was because the peptide hormone cannot cross the blood-brain barrier and so researchers believed that it was produced in hypothalamus and then secreted into blood veins. Researchers also believed that peptide hormone was made in endocrine glands and hypothalamus was the body’s endocrine gland.

Inferences 2nd paragraph:

These beliefs were questioned by laboratories. They injected antiserums into the brain and it started to bind in places other than hypothalamus. This indicated that peptide hormone maybe be present in the brain other than hypothalamus but this method is not precise. It has many drawbacks like : What antiserum detected was hormones only or something else. It also cannot detect the location in the body, as to where is this hormone produced?

Inferences 3rd paragraph:

To counter this, there is another method developed with the help of molecular biology. The researchers make specific DNA that would attach itself to the RNA of the peptide hormone. They will bind with other resembled or identical RNA but that bond will be strong. This way is faster than developing anti-serums and then isolating them. This research shows that peptide hormones are really made in the brain rather than hypothalamus. Though researchers have found where it is produced but they have not been able to find the function of the peptide hormone.

1. Which of the following titles best summaries the passage?

(A) Is Molecular Biology the Key to Understanding Intercellular Communication in the Brain?
Wrong. The function of the peptide hormone has not been established.

(B) Molecular Biology: Can Researchers Exploit Its Techniques to Synthesize Peptide Hormones?
Wrong. We are not synthesizing peptide hormone but are detecting its origin and it’s functions. Peptide hormones are made naturally by the body.

(C) The Advantages and Disadvantages of the Immunological Approach to Detecting Peptide Hormones
Wrong. This can be confusing as this offers the heading for the second paragraph but fails to take into account the third paragraph which is about molecular biology.

(D) Peptide Hormones: How Scientists Are Attempting to Solve Problems of Their Detection and to Understand Their Function
Right. The whole passage was concerned as to where the peptide hormone is made and what different ways scientists are using to find the origin of peptide hormone and its functions.

(E) Peptide Hormones: The Role Played by Messenger RNA's in Their Detection
Wrong. This also can be confusing as this is a headline for the third paragraph and not second. It does not take immunology techniques into account.

2. The passage suggests that a substance detected in the brain by use of antiserums to peptiDe hormones may

(A) have been stored in the brain for a long period of time
Wrong. It clearly says that the antiserum was binding everywhere other than the brain. As a second clue, it also said we cannot delete the location in the whole body as to where it is produced.

(B) play no role in the functioning of the brain
Wrong. They have not been able to come out of with the exact functioning of peptide hormone.

(C) have been produced in some part of the body other than the brain
Right. As it said it has not been produced in brains and we cannot locate it throughout the body.

(D) have escaped detection by molecular methods
Wrong. Molecular methods have been able to find such hormones faster and are more reliable.

(E) play an important role in the functioning of the hypothalamus
Wrong. We still have not been given any functioning of peptide hormone.

3. According to the passage, confirmation of the belief that peptide hormones are made in the brain in areas other than the hypothalamus would force scientists to

(A) reject the theory that peptide hormones are made by endocrine glands
Wrong.A confusing answer choice, but it has been mentioned that if the peptide hormones are made in the brain, this will force the scientists to develop a theory of functions of peptide hormones in the brain. Had it not been mentioned, this would have been the correct answer then.

(B) revise their beliefs about the ability of antiserums to detect peptide hormones
Wrong. The peptide hormone was detected by the help of molecular biology and not by anti-serums.

(C) invent techniques that would allow them to locate accurately brain cells that produce peptide hormones
Wrong. They want to know the use of peptide peptide hormone is the brain area.

(D) search for techniques that would enable them to distinguish peptide hormones from their close relatives
Wrong. The current techniques are enough for them to prove the peptide theory.

(E) develop a theory that explains the role played by peptide hormones in the brain
Correct. This has been mentioned in the last lines of the paragraph.

4. Which of the following is mentioned in the passage as a drawback of the immunological method of detecting peptide hormones?

(A) It cannot be used to detect the presence of growth regulators in the brain.
Wrong. We do not know if peptide is a growth regulator or not.

(B) It cannot distinguish between the pep 'tide hormones and substances that are very similar to them.
Right. This is the reason this method is so imprecise.

(C) It uses antiserums that are unable to cross the blood-brain barrier.
Wrong. It’s not antiserum that is not able to cross the blood-brain barrier but it’s the peptide hormone which is not able to cross the blood-brain barrier.

(D) It involves a purification proCess that requires extensive training in endocrinology:
Wrong. The purification process requires time and not extensive training.

(E) It involves injecting foreign substances directly into the bloodstream.
Wrong. The foreign substance was injected in both the methods.

5. The passage implies that, in doing research on rat brains, Rosen discovered that

(A) peptide hormones are used for intercellular communication
Wrong. It has nowhere been mentioned that peptide hormones are used for intercellular communication.

(B) complementary DNA do not bind to cells producing peptide hormones
Wrong. This research was not found out by Ross, but by other previous researchers.

(C) products closely resembling peptide hormones are not identical to peptide hormones
Wrong. This was again found out by previous researchers.

(D) some peptide hormones do not function as growth regulators
Correct. While still trying to know the functions of peptide hormones, some people believed that it was a growth regulator. But Ross research indicates that this is not true.

(E) antiserums cross-react with substances that are not peptide hormones
Wrong. This whole theory is wrong.

6. Which of the following is a way in which the immunological method of detecting peptide hormones differs from the molecular method?

(A) The immunological method uses substances that react with products of hormone producing cells, whereas the molecular method uses substances that react with a specific component of the cells themselves.
Right. The immunological method reacts with the peptide hormones whereas the molecular method reacts with their DNA and RNA.

(B) The immunological method has produced results consistent with long-held beliefs about peptide hormones, whereas the molecular method has produced results that upset these beliefs.
Wrong. We are not talking about emotional beliefs but the actual results.

(C) The immunological method requires a great deal of expertise, whereas the molecular method has been used successfully by nonspecialists.
Wrong. Yes, it has been mentioned that immunological methods do require a great deal of expertise but it has nowhere been mentioned that molecules require non-specialist.

(D) The immunological method can only be used to test for the presence of peptide hormones within the hypothalamus, whereas the molecular method can be used throughout the brain.
Wrong. Both the methods can test the presence of peptide hormone throughout the body.

(E) The immunological method uses probes that can only bind with peptide hormones, whereas the molecular method uses probes that bind with peptide hormones and substances similar to them.
Wrong. It’s quite the reverse. Immunology will bind with any hormone resembling peptide hormone.

7. The idea that the field of endocrinology can gain from developments in molecular biology is regarded by Roberts with

(A) incredulity
Unable to believe. But the doctor wants to believe that endocrinology is incomplete without molecular biology.

(B) derision
There was no mockery but instead a sense of relief that what immunology could not achiever in a short span of time, advancement in molecular biology have been able to give results.

(C) indifference
Wrong. There was no indifference.

(D) pride
Wrong. It cannot be pride because he didnt invent molecular biology.

(E) enthusiasm
Right.