You are researching a family with a heritable disease whose symptoms include hyper-flexible joints, pliable skin, stretchy ligaments, and fragile muscles that tear easily. You plan to use genetic testing to determine the cause of the disease. Which gene do you sequence first?

Question

A.  actin
B.  epidermal growth factor
C.  myosin II heavy chain
D.  collagen

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 the strengthening of tissues? 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.  collagen

Clarify Question
What is the key concept addressed by the question?
        · The concept addressed here is the identification of a gene product that reinforces tissue.
What type of thinking is required?
        · Evaluate level:
            o This question is asking you to weigh and judge, or evaluate, the gene that is most likely to produce a tissue-strengthening product.

Gather Content
What do you already know about the strengthening of tissues? What other information is related to the question?
        · A major strengthening component of a variety of different tissues is collagen.
        · Collagen is the most common protein in mammals.
        · In muscle tissue, although collagen is not especially abundant, it is found in the endomysium that surrounds individual muscle cells.

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · Epidermal growth factor does not strengthen tissue, it encourages the growth of tissue.
        · Actin and myosin serve in the contraction of muscles. While actin is a component of the cytoskeleton, it does not play a role in strengthening tissue.
        · Collagen is the logical choice here, as it is the most abundant protein in mammals, and it is known to strengthen tissue.
        · This example is similar to the disease known as Ehlers-Danlos Syndrome, which may be caused by the mutation of one of several collagen genes, or a few related genes.

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?
        · Evaluate level:
            o Answering this question correctly depended on your ability to weigh and judge, or evaluate, genes and their products as they relate to the strengthening of tissue. If you got an incorrect answer, did you remember that collagen is a protein that strengthens tissue, or that collagen is a component of many different tissues? Did you have trouble weighing the merits of collagen to determine the correct answer?