Consider the following biochemical pathway: (A is the initial substrate and D is

Question

Consider the following biochemical pathway:

(A is the initial substrate and D is the final product. The intermediate products are B and C. A is converted to B through the action of enzyme 1, B is converted to C through the action of enzyme 2, and C is converted to D through the action of enzyme 3.)

Use the above biochemical pathway to answer the following questions:

1. There is an accumulation of product C and no detectable amount of product D. What can you say about the pathway?

2. There is no product D being formed when substrate A is added. Adding product B does not correct the problem, but adding product C does. Where does the problem in the biochemical pathway lie?

3. Imagine that enzyme 3 is defective. Can you expect to overcome the problem and obtain the final product D by adding an excess of B? Why or why not?

Explanation / Answer

1) Enzyme 3 is defective because C isn't being converted to D 2) Enzyme 2 is definitely defective in this case. C is converted to D, so you know enzyme 3 is fine. B isn't being converted to D, but enzyme 3 is fine, so enzyme 2 has to be defective. Likewise with A (note that you can't draw a conclusion on whether or not enzyme 1 is defective, since it doesn't tell if you if A was converted to B, just that no D was formed). 3) If enzyme 3 is defective, adding extra B won't help. It will be converted to C, but without enzyme 3, C won't be converted to D. You'll just accumulate a lot of C, like in the first question.

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.