A words in context question with a final interpretation tests how later findings affect an earlier explanation. Read the whole text and follow the turn from the first explanation to the results that test it. Ask which idea the sentence with the blank refers to and what the later findings say about it. Then predict the blank in plain words. Check each word's meaning closely, because similar words can describe different changes or different amounts of change.
Hints
- Hint 1
Look for the first proposed mechanism. What did the researchers originally say caused the activity loss?
- Hint 2
Compare the later tests. What do the unattached peptide and the moved tag each reveal about the first explanation?
- Hint 3
Read the simulation result and the clause beginning with although, then check how far the evidence goes. What can the researchers conclude about the first mechanism?
Step-by-step
Follow the change in explanation
Step 1Identify the original mechanism
The first explanation attributed the loss primarily to the tag's histidines disrupting the enzyme's metal-containing active site. What does this initially proposed mechanism refer to? It's that chemical explanation, so the blank asks how the researchers' final view treats it. Removing the tag showed that the tag mattered, but didn't prove how it reduced activity.
- Step 2
Read the turn
The turn comes with Yet an unattached tag peptide had no effect. What else challenges the first explanation? The text says moving the attached tag to the enzyme's opposite end largely restored activity. The moved tag still had histidines, so where it sat mattered, which weakens the idea that its histidines were the main cause.
- Step 3
Predict how the view changed
Do the simulations rule the chemical mechanism out? They suggest the tag sometimes obstructed the substrate channel, which means it could block the path used by the substance the enzyme acts on. But weak chemical interactions with the active site remained possible. So predict gave the chemical explanation less weight: moving the tag and finding possible channel blocking suggest the chemical mechanism wasn't the main cause, without making it impossible.
- Step 4
Check the word meanings
Prioritized means put first, and reinforced means made stronger, so neither describes giving the chemical explanation less weight. Would overlooked, meaning failed to consider, fit? No, because weak chemical interactions with the active site remained possible. Deemphasized means gave less importance to, which describes a mechanism treated as less central, not ignored. Choice A.