Number 27, Test 1 on GRE big book RC

[glacier921]

Can anyone help me understand the answer?

 

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 .

 

 

27. If it were to be determined that "similar phenomena

occur in warm-blooded animals" (lines 21-22), 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

© 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

[Greenthu]

I think the answer is c . Is it the correct answer according to the book??

[arcticbelle]

A is incorrect because lowering body temperature will not help with bacterial infections, and might actually hurt.

 

B is incorrect because adding iron will make it easier for the bacteria to multiply.

 

E is incorrect because warm-bodied animals will regulate their own temperatures (or die if they get too hot), so changing the temperature of the room doesn't matter.

 

We're left with a choice between C and D: C has to do with making iron less available to ONLY the bacteria, while D has to do with making iron less available to BOTH animal and bacteria. D would deprive the animal of resources as well, so C is probably the best answer. Am I right?

[glacier921]

C is correct. Sorry for the long delay. I forgot about the passage though, I will have to reread, in the meanwhile, I went through the big book up to like test 18, and I think I am getting the hang of RCs for now. Thanks for the reply.

[Abhay Mone]

A is incorrect because lowering body temperature will not help with bacterial infections, and might actually hurt.

 

B is incorrect because adding iron will make it easier for the bacteria to multiply.

 

E is incorrect because warm-bodied animals will regulate their own temperatures (or die if they get too hot), so changing the temperature of the room doesn't matter.

 

We're left with a choice between C and D: C has to do with making iron less available to ONLY the bacteria, while D has to do with making iron less available to BOTH animal and bacteria. D would deprive the animal of resources as well, so C is probably the best answer. Am I right?

 

Hello,

I am bit confused with answer C. In the first half of passage we can see statement "Thus, fever would

make it more difficult for an infecting bacterium to acquire iron and thus to multiply" . As per my understanding,deficiency of iron make bacterium to multiply.Considering above opinion,I am going for option A.

Correct me if my understanding is wrong. Thanks!!!