AAMC Section Bank B/B #76: control

[br2pi5]

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For the control empty vector, do they mean there is no PRR present? or there is PRR but no ligand present?
When I first read the passage I thought the control meant no PRR (since it's not transfected with WT-PRR cDNA) but based on the other graph pairs since they all have some sort of ligand added to them (antagonist, agonist, antagonist + agonist) I decided to go with the thought that the control meant WT-PRR no ligand. Thoughts?

 

[NextStepTutor_1]

Hi @br2pi5 -

To fully answer this question, it's helpful to step back and look at the bigger context of the passage, in particular how Table 1 and Figure 1 relate to each other. (The short version is that they basically don't).

The passage tells you that WT-PRR is the gene that codes for the protein PRR. Table 1 tells us about variants in the protein PRR, and Q74 leads us to the conclusion that the point of this sub-experiment was to figure out which residues were involved in the function of the protein PRR. Figure 1 is a whole different experiment, in which the idea is to see whether overexpressing PRR (which is the effect of adding the WT-PRR vector) affects ROS production, and whether that relationship is affected by the presence of prorenin, an angiotensin II receptor antagonist, or a combination thereof. So the logic of Figure 1 can be summarized as: cloned WT-PRR cDNA --> overexpression of PRR (the protein) --> ??? in terms of effect on ROS, mediated by various conditions.

The empty vector is just a plasmid with some random stuff on it. The controls most likely express PRR as part of their default state (this is hinted at by the use of the word "overexpression" in Q76, and it makes sense that we'd want to use a cell type that we know is capable of expressing that receptor type), so the difference is that (a) the controls have a baseline level of PRR expression, with no effect from the empty vector, versus (b) the WT-PRR group overexpresses PRR due to the vector.

Hope this helps clarify the question, and the passage more broadly!!

 

[br2pi5]

Hi @br2pi5 -

To fully answer this question, it's helpful to step back and look at the bigger context of the passage, in particular how Table 1 and Figure 1 relate to each other. (The short version is that they basically don't).

The passage tells you that WT-PRR is the gene that codes for the protein PRR. Table 1 tells us about variants in the protein PRR, and Q74 leads us to the conclusion that the point of this sub-experiment was to figure out which residues were involved in the function of the protein PRR. Figure 1 is a whole different experiment, in which the idea is to see whether overexpressing PRR (which is the effect of adding the WT-PRR vector) affects ROS production, and whether that relationship is affected by the presence of prorenin, an angiotensin II receptor antagonist, or a combination thereof. So the logic of Figure 1 can be summarized as: cloned WT-PRR cDNA --> overexpression of PRR (the protein) --> ??? in terms of effect on ROS, mediated by various conditions.

The empty vector is just a plasmid with some random stuff on it. The controls most likely express PRR as part of their default state (this is hinted at by the use of the word "overexpression" in Q76, and it makes sense that we'd want to use a cell type that we know is capable of expressing that receptor type), so the difference is that (a) the controls have a baseline level of PRR expression, with no effect from the empty vector, versus (b) the WT-PRR group overexpresses PRR due to the vector.

Hope this helps clarify the question, and the passage more broadly!!

thank you as always! I will watch out for key words like "overexpression" next time. I was going over my final practice test (AAMC FL 3) and came across this P/S question that said alcohol dependence later in life was an example of negative reinforcement, how is that? when I think of negative reinforcement I think of removing a stimulus to increase a behavior (like a parent removing TV time so the child does his homework).
Ignore the fact that I quickly selected D -__- drinking alcohol is not an unconditioned response haha I think looking at the other options and through process of elimination I would end up choosing C but just wanted to make sure I had a good understanding of +/- reinforcement/punishment!

 

[br2pi5]

Also... for P/S #42 which has to do with conflict theory, how is the statement "religion encourages passive acceptance of material conditions" to do with social control and social inequality? or maybe this question just wanted you to realize that "religion helps to increase social solidarity"(answer D) has more to do with functionalism than conflict theory, and therefore D would definitely not have anything to do with conflict theory?

 

[NextStepTutor_1]

Hi @br2pi5 -

For alcohol dependence & negative reinforcement, the idea is that dependence is a situation where you need a substance to feel normal, so not having the substance "takes away" your ability to function normally, which corresponds to the "negative" part of negative reinforcement. The passage focuses on psychological aspects of dependence and the use of alcohol to "alleviate negative emotions", but the point about dependence applies more broadly, and you can see physical dependence and withdrawals from a substance through that lens as well.

For P/S #42, the implication is that "passive acceptance of material conditions" includes material inequality that is shaped by social control. "Passive" is a key word here, because it implies that the alternative would be some sort of active resistance, which may help underscore the connection with conflict theory. The choice involving social solidarity is a better pick because (for the purposes of the MCAT, anyway), solidarity is sort of like social cohesion -- it's a good thing in society and doesn't require any reference to conflict/inequality. I've had people point out w/ regard to this question that solidarity is often in opposition to something, which is an excellent point but goes somewhat beyond the scope of how in-depth the MCAT will want you to think about questions like that. In a nutshell, C points you more directly towards themes of inequality and control than D, which makes it the better answer in this situation.

Hope this helps clarify those questions!!