Mike has just returned home from college for the summer and notices that his 8-year old Dalmation dog Patches is limping and has difficulty walking up and down stairs. When Mike takes Patches to the vet, the vet recommends that Mike put him on a low-purine diet. This dietary change will lessen the formation of painful precipitates of ___________ in Patches' joints.

Question

A.  ammonia
B.  urea
C.  adenine and guanine
D.  uric acid
E.  NaCl

Clarify Question
What is the key concept addressed by the question?
What type of thinking is required?
 
Gather Content
What do you already know about purine? What other information is related to the question?

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
 
Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

D.  uric acid

Clarify Question
What is the key concept addressed by the question?
        · This question is asking about the precipitates that can form in the joints of mammals as a result of purine in the diet.
What type of thinking is required?
        · Apply level:
            o You are being asked to take what you already know and use, or apply, it to the effects of purine in the diet of a mammal.
 
Gather Content
What do you already know about purine? What other information is related to the question?
        · Mammals produce uric acid as the result of the breakdown of purine.
        · Humans, other primates, and the Dalmation dog breed lack the enzyme uricase, which transforms uric acid into allantoin.
        · Since they lack this enzyme, these specific mammals may accumulate uric acid in the joints, which can be painful.
        · The accumulation of uric acid in the joints is called gout.
 
Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · Since he is a Dalmatian, the painful joints that Patches is experiencing do correspond with the idea of gout.
        · Gout is the result of the breakdown of purine, a dietary component.
        · A low-purine diet would lessen the occurrence of uric acid precipitates in the joints.
 
Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        · Apply level:
            o Answering this question correctly depended on your ability to use the effects of purine in the diet in a new situation. If you got an incorrect answer, did you remember that purine is broken down into uric acid, and certain mammals lack the enzyme to break uric acid down further, so it may form precipitates in the joints of those mammals? Did you have trouble extending the metabolism of purine to determine the correct answer?