A major genetic cause of emphysema is deficiency of the protein alpha-1 anti-trypsin (AAT). AAT is an enzyme that inhibits the activity of another protein. What protein is most likely the normally-inhibited target of AAT?

Question

A.  elastin-specific protease
B.  hemocyanin
C.  hemoglobin
D.  collagen
E.  myoglobin
F.  carbonic anhydrase

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 emphysema? 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

A.  elastin-specific protease

Clarify Question
What is the key concept addressed by the question?
        · This question is asking about the conditions that result in emphysema.
What type of thinking is required?
        · Apply level:
            o You are being asked to take what you already know and apply it to the genetic causes of emphysema.

Gather Content
What do you already know about emphysema? What other information is related to the question?
        · Breathing requires expansion and recoil of breathing structures such as the lungs and the alveoli.
        · Emphysema is a disease that makes breathing very difficult.
        · Emphysema can be caused by a genetic mutation, but is most often caused by cigarette smoking.
        · Emphysema involves the break down of the walls of alveoli.
        · Emphysema results in a greater number of larger alveoli.
        · The lungs of someone with emphysema become less elastic, and moving air becomes much more difficult.
 
Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · Hemocyanin is similar to hemoglobin, but it is characteristic of molluscs.
        · Myoglobin and hemoglobin bind with oxygen, but are not involved in the physical mechanics of breathing.
        · Similarly, carbonic anhydrase converts carbon dioxide and water into bicarbonate, but is not involves in the mechanics of breathing.
        · Collagen is a critical protein for the structure and function of the lungs.
        · Proteases are enzymes that break down protein, so elastin-specific protease would break down elastic proteins and would contribute to emphysema. This enzyme would need to be inhibited to prevent these changes from occurring.
 
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 nature of normal lung structure in a new situation. If you got an incorrect answer, did you remember that the structure of lungs is dynamic, or that emphysema results in a loss of this elasticity? Did you have trouble extending the nature of lung structure to determine the correct answer?