What am I missing?

[MTD52]

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Is this a is poorly worded question, or should I have interpreted it differently (from Kaplan book)?

Trypsin and chymotrypsin cleave protein polypeptide chains at or between:
(a) the same site
(b) different sites
(c) arginine and lysine residues for trypsin and aromatic residues for chymotypsin
(d) a, b, and c are correct
(e) both a and b are correct

The passage states that...Trypsin breaks polypeptide chains on the carboxyl side of arginine and lysine residues. Chymotrypsin cleaves preferentially on the carboxyl side of aromatic and other bulky non polar amino acids.

I chose (c) because I thought that the fact they cleave at the carboxyl group was the same site, but just on different types of proteins. Correct answer says (e), saying they are different sites



Here's another one. Question:

Which of the following compounds can act as electron carriers in oxidative phosphorylation?
(a) NADP+
(b) NAD+
(c) Both NADP+ and NAD+
(d) ATP
(e) None of the above

I chose (e) because the actual electron carriers are NADH and NADPH after NAD+ and NADP+ are reduced, no? Correct answer said (c).

 

[jay47]

Is this a is poorly worded question, or should I have interpreted it differently (from Kaplan book)?

Trypsin and chymotrypsin cleave protein polypeptide chains at or between:
(a) the same site
(b) different sites
(c) arginine and lysine residues for trypsin and aromatic residues for chymotypsin
(d) a, b, and c are correct
(e) both a and b are correct

The passage states that...Trypsin breaks polypeptide chains on the carboxyl side of arginine and lysine residues. Chymotrypsin cleaves preferentially on the carboxyl side of aromatic and other bulky non polar amino acids.

I chose (c) because I thought that the fact they cleave at the carboxyl group was the same site, but just on different types of proteins. Correct answer says (e), saying they are different sites



Here's another one. Question:

Which of the following compounds can act as electron carriers in oxidative phosphorylation?
(a) NADP+
(b) NAD+
(c) Both NADP+ and NAD+
(d) ATP
(e) None of the above

I chose (e) because the actual electron carriers are NADH and NADPH after NAD+ and NADP+ are reduced, no? Correct answer said (c).

I teach for Kaplan and that first question is a bunch of crap. You cannot have contradictory answer choices and then say both are right. There won't be anything this stupid or ambiguous on the real exam, I promise. The best answer to that question is C, don't worry about it. I probably need to submit this one to the errata department...

I do agree with their choice on this question, so C is correct. I think you just overthought it. Even the wording is correct, NAD+ and NADP+ "can" act as electron carriers. Remember NAD+ and NADP+ are cofactors, so they are molecules themselves, and they can carry the electrons in an H+. Think of them as trucks, but without a load. The trucks are "capable" of carrying a load, even if they don't have one. This is analogous to NAD+ and NADP+. Take a look at this...

http://en.wikipedia.org/wiki/File:NAD_oxidation_reduction.svg

 

[Extirpator]

I teach for Kaplan and that first question is a bunch of crap. You cannot have contradictory answer choices and then say both are right. There won't be anything this stupid or ambiguous on the real exam, I promise. The best answer to that question is C, don't worry about it. I probably need to submit this one to the errata department...

I do agree with their choice on this question, so C is correct. I think you just overthought it. Even the wording is correct, NAD+ and NADP+ "can" act as electron carriers. Remember NAD+ and NADP+ are cofactors, so they are molecules themselves, and they can carry the electrons in an H+. Think of them as trucks, but without a load. The trucks are "capable" of carrying a load, even if they don't have one. This is analogous to NAD+ and NADP+. Take a look at this...

http://en.wikipedia.org/wiki/File:NAD_oxidation_reduction.svg

Second question is definately correct... but wouldn't the first one be correct too? I don't remember exactly from my course that covered this, but under different conditions they can cleave at the same OR diffent sites... could be wrong, but that was my initial thought when I read the question

 

[MTD52]

I teach for Kaplan and that first question is a bunch of crap. You cannot have contradictory answer choices and then say both are right. There won't be anything this stupid or ambiguous on the real exam, I promise. The best answer to that question is C, don't worry about it. I probably need to submit this one to the errata department...

I do agree with their choice on this question, so C is correct. I think you just overthought it. Even the wording is correct, NAD+ and NADP+ "can" act as electron carriers. Remember NAD+ and NADP+ are cofactors, so they are molecules themselves, and they can carry the electrons in an H+. Think of them as trucks, but without a load. The trucks are "capable" of carrying a load, even if they don't have one. This is analogous to NAD+ and NADP+. Take a look at this...

http://en.wikipedia.org/wiki/File:NAD_oxidation_reduction.svg

Yeah I guess that makes sense for the second question. I understand how the system works. I just got confused because in the passage it specifically states, "NAD+ or NADP+ are energized with electrons to form NADH or NADPH respectively, and both can be used as electron carriers. NADH is an active electron carrier..." So I just thought they weren't actually considered electron carriers until the electrons were on them?


Oh and I just realized I totally screwed up answer choice (e) on the first question - it's supposed to be the choice b and c are correct, not a and b. I still think (c) is the best answer for the first question though, no?