Next Step test 9-bio section. question 6

[Pediateix]

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i don't get the explanation

cellular and a peripheral protein. Peripheral proteins attach to integral membrane proteins or are anchored in the lipid bilayer via a hydrophobic domain. The passage states that phospholipase A2 is a membrane-bound enzyme and that it responds to binding of intracellular calcium. This implies that phospholipase A2 is likely a peripheral protein, as it is membrane-bound and as it must contain a cytosolic domain in order to bind to intracellular calcium.


where in the passage does it say Phospholipase A2 responds to Ca2+

@Next Step Tutor @NextStepTutor_1 @NextStepTutor_3

 

[Nugester]

i don't get the explanation

cellular and a peripheral protein. Peripheral proteins attach to integral membrane proteins or are anchored in the lipid bilayer via a hydrophobic domain. The passage states that phospholipase A2 is a membrane-bound enzyme and that it responds to binding of intracellular calcium. This implies that phospholipase A2 is likely a peripheral protein, as it is membrane-bound and as it must contain a cytosolic domain in order to bind to intracellular calcium.


where in the passage does it say Phospholipase A2 responds to Ca2+

@Next Step Tutor @NextStepTutor_1 @NextStepTutor_3

If the ns tutors don't respond, post the passage and I'll try to help you.

 

[Pediateix]

If the ns tutors don't respond, post the passage and I'll try to help you.

thanks. i will if they don't

i also don't get this question

 

[Pediateix]

don't get this question either

 

[NextStepTutor_1]

Hi Nugester & Pediateix --

Taking the questions one by one...

Q6: The statement that phospholipase A2 releases arachidonic acid that has been incorporated in membrane phospholipids is an important clue to answering the question, but you're right that the passage doesn't discuss Ca2+ directly. We'll revise the explanation to address the issue.

Q42: The basic idea here is that you need to combine two pieces of information from the passage: (1) that HR-mediated repair involves 3' resection and (2) that 5-MeC is more likely to spontaneously undergo oxidative deamination. These two facts point you in the direction of B, while C and D are not directly supported by the passage (although you do have to read these options pretty carefully to recognize that the logic is incorrect in these choices).

Q44: This question hinges on closely analyzing the logic proposed in the question stem and the answer choices. The scenario proposed in the question stem is essentially that HR repair --> CpG mutations. Let's work through the answer choices and how they fit into that hypothesis. A is irrelevant -- we have no indication that the timing w/ regard to HR repair would matter. B is correct, essentially because the findings shown in Table 1 can only be used to draw conclusions about HR repair if you assume that DSBs are repaired via HR repair. C is out of left field. D is tempting but you have to watch the logic carefully. If HR is not required for CpG site mutation, it that just means that there are other ways for those mutations to happen. That's OK -- the question stem doesn't state that HR repair is the only way for those mutations to occur. To frame this more schematically, imagine that thing C can be caused by things A and B. We could say that "thing A is not required for thing C" in such a situation because thing B provides an alternate pathway, but that doesn't actually contradict the idea that thing A also causes thing C. Therefore, B is the best answer.

Hope this is helpful & best of luck!