Re: Warm-blooded animals have elaborate physiological controls t
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03 Sep 2024, 01:39
1. The passage is primarily concerned with attempts to determine
(A) the role of siderophores in the synthesis of serum iron
This is mentioned but is not the primary purpose of the passage
(B) new treatments for infections that are caused by A. hydrophilia
No.
(C) the function of fever in warm-blooded animals
Yes. The entire passage is dedicated to answering the questions -"Why then during sickness should temperature rise, apparently increasing stress on the infected organism?
(D) the mechanisms that ensure constant body temperature
The passage is not interested in the mechanisms that maintain constant body temperature.
(E) iron utilization in cold-blooded animals
No.
2. According to the passage, Garibaldi determined which of the following?
(A) That serum iron is produced through microbial synthesis.
No.
(B) That microbial synthesis of siderophores in warm-blooded animals is more efficient at higher temperatures.
No. It is the other way around. He discovered that the microbial synthesis of siderophores in warm-blooded animals is inefficient at higher temperatures.
(C) That only iron bound to other substances can be used by bacteria.
No.
(D) That there is a relationship between the synthesis of siderophores in bacteria of the genus Salmonella and environmental temperature.
Yes. He found that microbial synthesis of siderophores—substances that bind iron—in bacteria of the genus Salmonella declined at environmental temperatures above 37°C and stopped at 40.3°C.
(E) That bacteria of the genus Salmonella require iron as a nutrient.
It is not mentioned in the passage that he determined that bacteria of the genus Salmonella require iron as a nutrient.
3. Which of the following can be inferred about warm-blooded animals solely on the basis of information in the passage?
(A) The body temperatures of warm-blooded animals cannot be easily controlled in the laboratory.
Yes. The following sentences in the passage reveal this - "Cold-blooded animals were used to test this hypothesis because their body temperature can be controlled in the laboratory."
(B) Warm-blooded animals require more iron in periods of stress than they do at other times.
Not mentioned in the passage.
(C) Warm-blooded animals are more comfortable at an environmental temperature of 37°C than they are at a temperature of 42°C.
Not mentioned in the passage.
(D) In warm-blooded animals, bacteria are responsible for the production of siderophores, which, in turn, make iron available to the animal.
Not mentioned in the passage. The bacteria, according to the passage synthesize siderophores which bind iron for their own consumption and not the animal.
(E) In warm-blooded animals, infections that lead to fever are usually traceable to bacteria.
Not mentioned in the passage.
4. If it were to be determined that “similar phenomena occur in warm-blooded animals”, which of the following, assuming each is possible, is likely to be the most effective treatment for warm-blooded animals with bacterial infections?
What are the similar phenomena? It is the reduction in mortality rates at higher temperatures in iguanas reversed when iron solution was injected. Therefore, since injection of iron solution (which increases availability of iron to A.hydrophilia) plays a crucial role in increasing mortality rates, the most effective treatment for warm-blooded animals would be a method which denies iron availability to the bacteria.
(A) Administering a medication that lowers the animals’ body temperature
Assuming it is possible to lower the body temperature of a warm-blooded animal without affecting its health, no, it is not the most effective treatment. It will improve the bacteria's ability to intake iron and thus increase the intensity of sickness in the animal.
(B) Injecting the animals with an iron solution
No. It will improve the bacteria's ability to intake iron and thus increase the intensity of sickness in the animal.
(C) Administering a medication that makes serum iron unavailable to bacteria
Yes. This will deny iron to the bacteria, prevent it from multiplying, and thus reduce the infection.
(D) Providing the animals with reduced-iron diets
Not the most effective.
(E) Keeping the animals in an environment with temperatures higher than 37°C
No, since it is a warm-blooded animal, this may not be possible.
