Warm-blooded animals have elaborate physiological controls to maintain

Question

(This passage is excerpted from an article that was published in 1982.)

Warm-blooded animals have elaborate physiological controls to maintain constant body temperature (in humans, 37°C). Why then during sickness should temperature rise, apparently increasing stress on the infected organism? It has long been known that the level of serum iron in animals falls during infection. Garibaldi first suggested a relationship between fever and iron. 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. Thus, fever would make it more difficult for an infecting bacterium to acquire iron and thus to multiply. Cold-blooded animals were used to test this hypothesis because their body temperature can be controlled in the laboratory. Kluger reported that of iguanas infected with the potentially lethal bacterium A. hydrophilia, more survived at temperatures of 42°C than at 37°C, even though healthy animals prefer the lower temperature. When animals at 42°C were injected with an iron solution, however, mortality rates increased significantly. Research to determine whether  similar phenomena occur in warm-blooded animals  is sorely needed.   1 
 1. The passage is primarily concerned with attempts to determine

(A) the role of siderophores in the synthesis of serum iron
(B) new treatments for infections that are caused by A. hydrophilia
(C) the function of fever in warm-blooded animals
(D) the mechanisms that ensure constant body temperature
(E) iron utilization in cold-blooded animals

2 
 2. According to the passage, Garibaldi determined which of the following?

(A) That serum iron is produced through microbial synthesis.
(B) That microbial synthesis of siderophores in warm-blooded animals is more efficient at higher temperatures.
(C) That only iron bound to other substances can be used by bacteria.
(D) That there is a relationship between the synthesis of siderophores in bacteria of the genus Salmonella and environmental temperature.
(E) That bacteria of the genus Salmonella require iron as a nutrient.

3 
 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.
(B) Warm-blooded animals require more iron in periods of stress than they do at other times.
(C) Warm-blooded animals are more comfortable at an environmental temperature of 37°C than they are at a temperature of 42°C.
(D) In warm-blooded animals, bacteria are responsible for the production of siderophores, which, in turn, make iron available to the animal.
(E) In warm-blooded animals, infections that lead to fever are usually traceable to bacteria.

4 
 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?

(A) Administering a medication that lowers the animals’ body temperature
(B) Injecting the animals with an iron solution
(C) Administering a medication that makes serum iron unavailable to bacteria
(D) Providing the animals with reduced-iron diets
(E) Keeping the animals in an environment with temperatures higher than 37°C

Sajjad1994 · Answer

Explanation

1. The passage is primarily concerned with attempts to determine

Explanation

This is a global question so keep the possible intentions of author in your mind. Lets have a look at each answer choice

A, B and E are easy to eliminate. C and D looks close. D is wrong because author is not looking for a  constant body temperature

The text which is important to know the intentions of the author is:

Warm-blooded animals have elaborate physiological controls to maintain constant body temperature (in humans, 37°C). Why then during sickness should temperature rise,

........Thus, fever would make it more difficult for an infecting bacterium to acquire iron and thus to multiply.

These above lines lead to the answer

Answer: C

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?

Explanation

This is a CR type question so one can use his/her CR abilities here.

A  and  C  are looking promising here,  B  is rather opposite. Read the lines in the passage.

When animals at 42°C were injected with an iron solution, however, mortality rates increased significantly.

C  is the correct answer, Read the lines:

It has long been known that the level of serum iron in animals falls during infection...............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. Thus, fever would make it more difficult for an infecting bacterium to acquire iron and thus to multiply.

Option D and E are using faulty information from the passage.

Answer: C

RamseyGooner · Answer

GMATNinja  I have a doubt on the question number 4.
When the author says  "similar phenomena occur in warm-blooded animals" , the sentence immediately before that is "When animals at 42℃ were injected with an iron solution, however, mortality rates increased significantly".
So, shouldn't that be considered as the phenomena instead of the whole situation concerning the bacteria and everything?

Please help!

bM22 · Answer

Hi  RamseyGooner ,

The sentence immediately before the highlighted lines: "even though healthy animals prefer the lower temperature. When animals at 42℃ were injected with an iron solution, however, mortality rates increased significantly. ", is not a phenomenon, instead its a part of the experiments conducted to explain : "It has long been known  that the level of serum iron in animals falls during infection . "

Hope This Helps.
Thanks.

Sajjad1994 · Answer

Explanation

3. Which of the following can be inferred about warm-blooded animals solely on the basis of information in the passage?

Explanation

(A) The body temperatures of warm-blooded animals cannot be easily controlled in the laboratory. 
True: because the passage mentions  "Cold-blooded animals were used to test this hypothesis because their body temperature can be controlled in the laboratory" . From this, it can be inferred that warm-blooded animals' temperatures are harder to control in a lab.

(B) Warm-blooded animals require more iron in periods of stress than they do at other times. 
B- No info to infer any of this.

(C) Warm-blooded animals are more comfortable at an environmental temperature of 37°C than they are at a temperature of 42°C. 
C- This is true for iguana's, who are cold-blooded.

(D) In warm-blooded animals, bacteria are responsible for the production of siderophores, which, in turn, make iron available to the animal. 
Just an amalgam of incorrect info.

(E) In warm-blooded animals, infections that lead to fever are usually traceable to bacteria. 
No such pattern is mentioned.

Answer: A

VerbalBot · Answer

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Warm-blooded animals have elaborate physiological controls to maintain

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Warm-blooded animals have elaborate physiological controls to maintain

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