AAMC CBT7 and 7R OFFICIAL Q&A

[Vihsadas]

This is the official Q&A thread for AAMC CBT7 and 7R.

Please post ONLY questions pertaining to AAMC CBT7 and 7R.
Out of respect for people who may not have completed the other exams, do not post questions or material from any other AAMC exam.

Please see this thread for the rules of order before you post.

Good luck on your MCAT!

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[gettheleadout]

#128 in BS - there is no way this question is valid.

An infection in the stomach mucosa involves the H. pylori bacteria proliferating within the epithelia and connective tissue, and antibodies are delivered to these tissues through the vasculature, not into the lumen of the stomach. This is especially apparent when you consider that mucosa-associated lymphatic tissue exists for that very reason.

Choice A simply cannot be considered, which makes C correct by default. I've also consulted a PhD anatomist on this and he agreed.

 

[sakabato93]

#128 in BS - there is no way this question is valid.

An infection in the stomach mucosa involves the H. pylori bacteria proliferating within the epithelia and connective tissue, and antibodies are delivered to these tissues through the vasculature, not into the lumen of the stomach. This is especially apparent when you consider that mucosa-associated lymphatic tissue exists for that very reason.

Choice A simply cannot be considered, which makes C correct by default. I've also consulted a PhD anatomist on this and he agreed.

Your premise make sense, and I think its a very valid argument. But I think that you're forgetting that infection disrupts normal physiology and structure of the stomach lining. Yes, pathogen proliferation occurs with the epithelia and connective tissue, and at time the proliferation and infection may induce the formation of ulcers. Its reasonable to deduce that ulcers form because of breakdown of the mucous membrane that is associated with bacterial infection of the epithelia that produce these membranes. The lack of the mitigating effects of the mucous causes localized cell death in the form of ulcers. Furthermore, its reasonable to deduce that the breakdown of mucous-producing epithelia creates acidic conditions in the surroundings of the ulcer, including the cells and vasculature. These induced conditions could possibly denature antibodies.

You're operating under the assumption that the acidic conditions are localized within the lumen, which is true under normal conditions. But during conditions of infection, such assumptions are less likely to hold, especially when there is a link between the infection and abnormal conditions that induce delocalization of the acid (into surrounding tissues).

I doubt that C is as plausible because there doesn't seem to be any data that supports that claim in the passage, and it certainly isn't a "fact" that is critical to know for the MCAT.

I really want to hear the anatomist's explanation on this, though.

 

[gettheleadout]

Your premise make sense, and I think its a very valid argument. But I think that you're forgetting that infection disrupts normal physiology and structure of the stomach lining. Yes, pathogen proliferation occurs with the epithelia and connective tissue, and at time the proliferation and infection may induce the formation of ulcers. Its reasonable to deduce that ulcers form because of breakdown of the mucous membrane that is associated with bacterial infection of the epithelia that produce these membranes. The lack of the mitigating effects of the mucous causes localized cell death in the form of ulcers. Furthermore, its reasonable to deduce that the breakdown of mucous-producing epithelia creates acidic conditions in the surroundings of the ulcer, including the cells and vasculature. These induced conditions could possibly denature antibodies.

You're operating under the assumption that the acidic conditions are localized within the lumen, which is true under normal conditions. But during conditions of infection, such assumptions are less likely to hold, especially when there is a link between the infection and abnormal conditions that induce delocalization of the acid (into surrounding tissues).

I doubt that C is as plausible because there doesn't seem to be any data that supports that claim in the passage, and it certainly isn't a "fact" that is critical to know for the MCAT.

I really want to hear the anatomist's explanation on this, though.

I considered the issue of luminal content invading the mucosa, because I realize the epithelium is obviously not intact when an ulcer is present, but there are several problems with this. H pylori locally neutralizes stomach acid via urease secretion, and the ammonia produced is partly what kills epithelial cells, not just the acidity of the fluid. With fluid immediately surrounding the bacteria sufficiently neutralized for them to survive, antibodies should be able to bind without denaturing. Further, the hyperemia associated with inflammation of the mucosa in the region of the ulcer means new plasma and other fluids are constantly being delivered to the area, along with antibodies, which should mitigate the encroaching acidity to some extent, if only by dilution.

It's not that I think we should know C is the answer because of any content knowledge, but I believe every test taker should read the question and immediately realize that antibodies aren't delivered into the lumen, they're presented first into the deepest tissues and move upward, so the infection should at the very least not progress, if not regress. C seems like the answer you're supposed to recognize as necessarily correct because A is relatively implausible, only seeming plausible if you have a superficial understanding (not saying you do sakabato) of the role of immune defense in the gastric regions.

 

[sakabato93]

I considered the issue of luminal content invading the mucosa, because I realize the epithelium is obviously not intact when an ulcer is present, but there are several problems with this. H pylori locally neutralizes stomach acid via urease secretion, and the ammonia produced is partly what kills epithelial cells, not just the acidity of the fluid. With fluid immediately surrounding the bacteria sufficiently neutralized for them to survive, antibodies should be able to bind without denaturing. Further, the hyperemia associated with inflammation of the mucosa in the region of the ulcer means new plasma and other fluids are constantly being delivered to the area, along with antibodies, which should mitigate the encroaching acidity to some extent, if only by dilution.

It's not that I think we should know C is the answer because of any content knowledge, but I believe every test taker should read the question and immediately realize that antibodies aren't delivered into the lumen, they're presented first into the deepest tissues and move upward, so the infection should at the very least not progress, if not regress. C seems like the answer you're supposed to recognize as necessarily correct because A is relatively implausible, only seeming plausible if you have a superficial understanding (not saying you do sakabato) of the role of immune defense in the gastric regions.

That's quite a lot of excess information to consider, haha.

It makes sense, but I still feel as though C is more implausible to begin with. All-in-all, I agree in that this question seems fairly invalid, though.

 

[gettheleadout]

That's quite a lot of excess information to consider, haha.

It makes sense, but I still feel as though C is more implausible to begin with. All-in-all, I agree in that this question seems fairly invalid, though.

Haha I recognize that, don't get me wrong. No one is expected to know the urease/ammonia thing, I had to look that up, but everyone should know what inflammation entails and also how antibodies are delivered to the tissues.

I agree though, it's a bad question. I think the way I see it is I have reason to suspect A is implausible, while I have no reason to believe either way on C. Ergo, C. Appreciate discussing it with you! I really hope this kind of thing isn't a trend on the current MCAT though, is it so much to ask that every science question have a 100% justifiable incontrovertible answer?

On another note, I find the answer explanation on BS #144 to be incomprehensible haha.

 

[sakabato93]

On another note, I find the answer explanation on BS #144 to be incomprehensible haha.

I'm on it!

Never mind. I got it right, but I guess it was more intuition when I took the test.

 

[sakabato93]

I agree though, it's a bad question. I think the way I see it is I have reason to suspect A is implausible, while I have no reason to believe either way on C. Ergo, C. Appreciate discussing it with you! I really hope this kind of thing isn't a trend on the current MCAT though, is it so much to ask that every science question have a 100% justifiable incontrovertible answer?

Ditto.

At least its only a once in while occurrence... But AAMC does have really lazy answer explanations to begin with.

 

[gettheleadout]

I'm on it!

Never mind. I got it right, but I guess it was more intuition when I took the test.

When I reviewed it, I realized that I could have done a really simple math check in my head to determine the correct answer, I just didn't realize it was necessary. Even now though, I don't totally understand what they wanted us to get out of the question and chart, their answer explanation just makes it more confusing. Oh well, I'm not dwelling on it.

Ditto.

At least its only a once in while occurrence... But AAMC does have really lazy answer explanations to begin with.

Haha you ever notice that certain explanations are written by certain people? I can tell differences in their tone and word choice that give it away.

 

[Neutral]

Haha I recognize that, don't get me wrong. No one is expected to know the urease/ammonia thing, I had to look that up, but everyone should know what inflammation entails and also how antibodies are delivered to the tissues.

I agree though, it's a bad question. I think the way I see it is I have reason to suspect A is implausible, while I have no reason to believe either way on C. Ergo, C. Appreciate discussing it with you! I really hope this kind of thing isn't a trend on the current MCAT though, is it so much to ask that every science question have a 100% justifiable incontrovertible answer?

On another note, I find the answer explanation on BS #144 to be incomprehensible haha.

I completely agree on the science of your argument (and like the question we were talking about earlier regarding ideal gases, it is a bad question), though perhaps my reasoning of why I eliminated C can shed some light on the issue.

C says "H. pylori infection may suppress the activity of the immune system"

The last sentence of the passage says "Although many individuals develop antibodies against H. pylori antigens, these antibodies rarely eradicate the infection; evidently, this pathogen has developed effective ways to elude host defenses"

Judging from that sentence, it would seem that the immune system functions normally with normal activity, while H. Pylori isn't affected by it.

The fact that antibodies are being developed, and the use of the word elude suggests that it escapes rather than suppresses. This may be a case of "take whatever is in the passage as law no matter what".

 

[sakabato93]

When I reviewed it, I realized that I could have done a really simple math check in my head to determine the correct answer, I just didn't realize it was necessary. Even now though, I don't totally understand what they wanted us to get out of the question and chart, their answer explanation just makes it more confusing. Oh well, I'm not dwelling on it.


Haha you ever notice that certain explanations are written by certain people? I can tell differences in their tone and word choice that give it away.

Oh most definitely.

 

[gettheleadout]

I completely agree on the science of your argument (and like the question we were talking about earlier regarding ideal gases, it is a bad question), though perhaps my reasoning of why I eliminated C can shed some light on the issue.

C says "H. pylori infection may suppress the activity of the immune system"

The last sentence of the passage says "Although many individuals develop antibodies against H. pylori antigens, these antibodies rarely eradicate the infection; evidently, this pathogen has developed effective ways to elude host defenses"

Judging from that sentence, it would seem that the immune system functions normally with normal activity, while H. Pylori isn't affected by it.

The fact that antibodies are being developed, and the use of the word elude suggests that it escapes rather than suppresses. This may be a case of "take whatever is in the passage as law no matter what".

I understand that approach, and I remember thinking about that passage sentence when I answered the question. The thing is, I can see the explanation going "since it is suggested that the bacteria "elude" the immune system by some means, it can be inferred that it is plausible for the bacteria to have other anti-immunogenic adaptations as well, interacting with the immune system in a similar way to their means of evading it."

It's so lame haha, science questions shouldn't be up to interpretation.

 

[Neutral]

Yeah 144.. spent so long on that question wtf

 

[Synapsis]

Yeah 144.. spent so long on that question wtf

I got it right, but imo, one of those hardest questions on the test. Even looking back, my logic, which was way different than AAMC's, doesn't seem as plausible as it felt during the test.

EDIT: May as well share my thought process. Since the graph showed percentage of cells with basically radioactive T, and the 3-13 hour period involves an increase and a decrease, I asked what process would involve and increase and a decrease. Now they washed all the radioactive T out and let the cells divide. Because DNA synthesis is semiconservative, after replication, less of the cells would have the radioactive T and some would have normal T (remembering that the radioactive T was washed away). After another round of replication, the max percent of cells with radioactive T would decrease still further because there are even more cells produced with normal T. This makes sense if you look at the second dashed area of the graph, which, upon extrapolation, might show a smaller second peak. Maybe not the best way to look at it, and even now it doesn't make as much sense, but I guess it worked.

 

[Temperature101]

I think question 20 on PS is a bit unfair;

The questions reads: A gas that occupies 10 L at 1 atm and 25 C will occupy what volume at 500 atm and 25 C.

The correct answer is b, Somewhat more than .02 L because of the space occupied by the individual gas molecules. I really wanted to put this answer, but I changed it to A (exactly .02L) after I read choice C: Somewhat more than .02 L because of the repulsions between gas molecules.

If we are treating the gas as a real gas that does not behave ideally, then B is certainly correct - but so is C. If we are treating it non ideally then the repulsions between molecules is present, so we would treat it the same as how the molecules would have volume.

Since I saw these as two correct answers, I eliminated them and chose A, as it represented the gas as an ideal gas.

Am i missing something? I really feel like b and c are equally correct answers.

I got the right answer because I remember that BR Gen Chem has a question like that in the in-chapter GASES but it was if you decrease the pressure...

 

[gettheleadout]

I got it right, but imo, one of those hardest questions on the test. Even looking back, my logic, which was way different than AAMC's, doesn't seem as plausible as it felt during the test.

EDIT: May as well share my thought process. Since the graph showed percentage of cells with basically radioactive T, and the 3-13 hour period involves an increase and a decrease, I asked what process would involve and increase and a decrease. Now they washed all the radioactive T out and let the cells divide. Because DNA synthesis is semiconservative, after replication, less of the cells would have the radioactive T and some would have normal T (remembering that the radioactive T was washed away). After another round of replication, the max percent of cells with radioactive T would decrease still further because there are even more cells produced with normal T. This makes sense if you look at the second dashed area of the graph, which, upon extrapolation, might show a smaller second peak. Maybe not the best way to look at it, and even now it doesn't make as much sense, but I guess it worked.

There are so many problems with that question...

Is extracellular dT washed away? Or by "unabsorbed" do they mean all dT not incorporated into newly synthesized nucleic acid? Is there intracellular dT left for future synthesis after washout? The explanation uses "unincorporated" instead of "unabsorbed," while itself specifically denoting "incorporation" to refer to addition into new nucleic acid. If there is no dT left in the culture at all save for that already incorporated into nucleic acids synthesized during treatment, then the entire experiment is nonsensical because the percentage can never change. If there is intracellular dT left after washout, then by "unabsorbed" the question stem must be referring to cellular uptake instead of synthetic incorporation.

This would lead one to believe that they must be referring to only extracellular dT removal at washout, but even assuming that, the experiment doesn't make any sense. The answer explanation goes on to say that cells mitotically active >13 hours post-treatment were not radioactive because they were not in S phase during treatment, and thus did not incorporate any dT into their actively synthesized nucleic acids. However, even cells outside S phase would take up extracellular dT, which would be retained and incorporated into new nucleic acid once synthesis began the next cycle.

So what's being washed away? Either option gives you nonsensical data.

Edit: Ah, I see what it is. Because the experiment measures radioactivity in actively dividing nuclei, the percentage only changes if 1) the cells are not synchronized in cell cycle, and 2) the washout actually removes all extra- and intracellular dT. The results make sense given those conditions.

HOWEVER, "unabsorbed" is the worst possible way to try to refer to dT not incorporated into new nucleic acid. Fluid added to culture is absorbed by cells, as with stains. "Incorporation" specifically refers to synthetic inclusion.

I deem the question invalid and misleading due to wording.

 

[Neutral]

On a different note - for question 109, are those areas of the bodies we simply should know? I have never actually heard of the perineum or the pleural cavity, and have maybe heard of peritoneal cavity once or twice.

 

[Temperature101]

On a different note - for question 109, are those areas of the bodies we simply should know? I have never actually heard of the perineum or the pleural cavity, and have maybe heard of peritoneal cavity once or twice.

That was an anatomy question. It was probably the easiest question on the test for people who took anatomy.... Sometimes AAMC does strange stuff...

 

[gettheleadout]

On a different note - for question 109, are those areas of the bodies we simply should know? I have never actually heard of the perineum or the pleural cavity, and have maybe heard of peritoneal cavity once or twice.

You should know pleural cavity. Perineum is definitely not common knowledge and peritoneum/peritoneal cavity only slightly more likely to be encountered. I knew all of them, but definitely not from any coursework or prep book.

Hard discrete, indeed.

 

[Temperature101]

You should know pleural cavity. Perineum is definitely not common knowledge and peritoneum/peritoneal cavity only slightly more likely to be encountered. I knew all of them, but definitely not from any coursework or prep book.

Hard discrete, indeed.

I think it was from a passage...

 

[gettheleadout]

I think it was from a passage...

Ah you're right, it was, but it wasn't actually answerable based on passage information.

 

[Synapsis]

I actually only got that question based on what I remembered from HS Biology. The kidneys are retroperitoneal, which is near the back of the abdominal cavity. That led me to believe the peritoneal cavity was the general abdominal area.

This is why I completely disagree with the idea that one should focus completely on data analysis and only little on bio memorization. You gotta know everything - the AAMC is going for a distribution and one way to get it is to ask narrow content questions.

 

[Temperature101]

I actually only got that question based on what I remembered from HS Biology. The kidneys are retroperitoneal, which is near the back of the abdominal cavity. That let me to believe the peritoneal cavity was the general abdominal area.

This is why I completely disagree with the idea that one should focus completely on data analysis and only little on bio memorization. You gotta know everything - the AAMC is going for a distribution and one way to get it is to ask narrow content questions.

I agree... Even the famous AAMC 10 BS that most people say relied heavily on experimental passages, over 50% of the questions require some knowledge-based biology and Ochem content.

 

[Neutral]

Ok final question - 144

If the 3-13 hour step is during DNA synthesis, why would there be a peak? I would think that during DNA synthesis the % of cells with the label would only increase, since the cells are synthesizing new DNA, and the label is going into all the new DNA. Why would the % of cells with the label decrease at the ~10 hour mark?

Also in this thread there are people talking about questions with numbers greater than 144 - are there more questions? Whats the difference between CBT7 and 7R?

 

[gettheleadout]

Ok final question - 144

If the 3-13 hour step is during DNA synthesis, why would there be a peak? I would think that during DNA synthesis the % of cells with the label would only increase, since the cells are synthesizing new DNA, and the label is going into all the new DNA. Why would the % of cells with the label decrease at the ~10 hour mark?

Also in this thread there are people talking about questions with numbers greater than 144 - are there more questions? Whats the difference between CBT7 and 7R?

The y-axis is only measuring radioactivity in "actively dividing" cells. Because the cells in culture are all scattered around different places in the cell cycle, there will be some period of time during which the maximum number of cells that were in S phase during treatment will be undergoing mitosis simultaneously - this is the peak in radioactivity.

The R-version exams were the paper versions given before the shortening of the exam for CBT format; they have more questions. Some of those questions have presumably been incorporated into the AAMC self-assessments.

 

[Neutral]

The y-axis is only measuring radioactivity in "actively dividing" cells. Because the cells in culture are all scattered around different places in the cell cycle, there will be some period of time during which the maximum number of cells that were in S phase during treatment will be undergoing mitosis simultaneously - this is the peak in radioactivity.

The R-version exams were the paper versions given before the shortening of the exam for CBT format; they have more questions. Some of those questions have presumably been incorporated into the AAMC self-assessments.

If the cells are all scattered in the cell cycle, then how can we definitively say that the process that is occurring during the 3-13 hour mark is S phase? Wouldn't all phases be present during that that time?

 

[Heday]

If the cells are all scattered in the cell cycle, then how can we definitively say that the process that is occurring during the 3-13 hour mark is S phase? Wouldn't all phases be present during that that time?

The question ask "Based on the figure, the approximate length of what process is indicated by the 3-13 hour interval treatment with radioactive 2-deoxythymidine." So although we have cells in various phases of the cell cycle, the figure is showing the percentage of dividing nuclei with a radioactive label. During the 3-13 hour window, we see the number of cells peak with the radioactive label in their nuclei. So the 3-13 hour window represents a process in which the dividing nuclei incorporate nucletoides. The only time that the nuclei would incorporate nucleotides would be during the S phase.

 

[FeinMS]

The earthquake passage was ridiculous. And AAMC should provide better explanations. It seems like no one here has shared their thought on #44 (about minor energy wave causing an earthquake.)

Is this passage type where we have to treat it like VR current trend of recent MCAT?

Edit: I understood the problem, but seriously. For people in the future, the passage says "...surface waves are associated with elastic oscillations in the crust ... and cause little lasting deformation." The choice B implies that small energy waves cumulatively build up local stress (lasting deformation.) Therefore, B is incorrect.

 

[astronaut135]

Hi! I had a question on #147 (During the initial skin diving session, when her heart and breathing rates were increased, Sarah noticed that she produced more urine than usual. This was most probably a result of...). If Sarah's HR, Breathing rate, and BP were increased, why would her urine output be greater than normal? Isn't increased BP due to increased water retention and thus decreased urine output? Also, wouldn't the stimulation of the sympathetic nervous system also lead to decreased urine output?

I had the same question! anyone have an explanation?

 

[brood910]

can anyone explain #46 on the physical sciences. If a rupture is moving from south to north how does Doppler effect influence this? Thanks.

Bump.
I thought, to have a doppler's effect, you must have both receiver and source.
Where's the receiver here?

 

[dudewheresmymd]

Anyone have any insights on this one? Isn't A also a "true statement?"

 

[inasensegone]

Anyone have any insights on this one? Isn't A also a "true statement?"
View attachment 179858

No... it isn't the incorporation of bacterial genes into human chromosome that causes the cancer, that would be more representative of a viral action than bacteria.

 

[dudewheresmymd]

No... it isn't the incorporation of bacterial genes into human chromosome that causes the cancer, that would be more representative of a viral action than bacteria.

oh ok so even though A is a true statement "that humans do not incorporate bacterial genes into their chromosomes" it's not the best answer? (tolerate the infection w/o developing tumors) this seemed iffy to me.

 

[inasensegone]

oh ok so even though A is a true statement "that humans do not incorporate bacterial genes into their chromosomes" it's not the best answer? (tolerate the infection w/o developing tumors) this seemed iffy to me.

Oh I misread choice A... Yeah choice A might be a true answer, but it says nothing about whether or not tumors are developing. Helicobacter Pylori doesn't incorporate its genes into the chromosomes of the people that DO develop cancer, yet they still develop cancer. So choice A essentially applies to both types of patients and therefore does nothing to answer the question regardless of being a correct statement.

 

[dudewheresmymd]

Oh I misread choice A... Yeah choice A might be a true answer, but it says nothing about whether or not tumors are developing. Helicobacter Pylori doesn't incorporate its genes into the chromosomes of the people that DO develop cancer, yet they still develop cancer. So choice A essentially applies to both types of patients and therefore does nothing to answer the question regardless of being a correct statement.

brilliant.

 

[dudewheresmymd]

Also, is IgA the only antibody that can be secreted into lumen of respiratory/GI?

 

[inasensegone]

Also, is IgA the only antibody that can be secreted into lumen of respiratory/GI?

For reference:

To be honest, I think knowing where certain antibodies are secreted is beyond the scope of the MCAT. The only one I might be familiar with, is the fact that IgA is transferred to a newborn via the mother's breast milk and that this is a form of passive immunity.

This question can pretty much be answered based off of process of elimination. Antibodies are generally effective against bacteria, eliminate choice B. H. Pylori is unlikely to suppress the immune system, otherwise most people wouldn't ever be clear of the infection. Also, the passage mentions that people produce antibodies against the antigens... if they are producing antibodies then there is likely some other explanation as to why the antibodies are not effective, eliminate choice C. Antibodies are secreted from host tissues into extracellular spaces, otherwise what good would they do if they were bound up inside of a cell? Eliminate choice D. ---> choice A by default.

If Choice D had said that 'antibodies are not secreted from host tissues to the exterior of the body', then I could definitely see it as being a possible choice where knowing about the secretory routes of IgA would be useful, but other than that, I would stick to the basics.

 

[Dentsss]

Cool forum

 

[TheJourney]

For #96 in the BS section, how come the answer isn't answer choice D) 32?
The x is a chiral carbon and there are 3 chiral carbons within the ring. Also, the Nitrogen is bonded to a hydrogen, a CHO group and another R group and has a lone pair, wouldn't that make the nitrogen chiral and therefore resulting in a total of 5 chiral centers in the molecule and 2^5 = 32?

 

[kamikaze1992]

For #96 in the BS section, how come the answer isn't answer choice D) 32?
The x is a chiral carbon and there are 3 chiral carbons within the ring. Also, the Nitrogen is bonded to a hydrogen, a CHO group and another R group and has a lone pair, wouldn't that make the nitrogen chiral and therefore resulting in a total of 5 chiral centers in the molecule and 2^5 = 32?

Check carefully, chiral centers refer to carbons. There are 4 chiral carbons in the figure.

 

[kamikaze1992]

Verbal AAMC 7 R
114. Former low level employees who secure managerial positions in their company get more sophisticated equipment and more work related training than they had before. What relationships to info provided in the passage does this fact most plausibly suggest?

a) It supports the conclusion that occupational preparation and access to training are complementary
b) It opposes the assertion that power is shared in firms committed to training of employees
c) It exemplifies that inequities that exist in firms that are unable to follow the high road
d) It helps to explain the increasing disparity in earnings between management and workers.

Why is the answer choice c? I don't see any evidence fort this

 

[SuperSneaky24]

So I didn't really understand this question:

(AAMC 7R #63) When tires are made of hard rubber, the coefficients of rolling, sliding, and static friction with the road are reduced compared with softer rubber. Which of the following predictions would NOT hold if hard rubber replaced soft rubber in tire manufacture?

A)Stopping distances would increase.
B) Fuel efficiency would be unchanged.
C) Slippage on curves would be more likely.
D)Higher tire air pressure would be required.

I don't exactly understand why the answer is D. I thought D would hold true because P=F/A. When you use a tire that reduces friction, you would want more frictional force to stop the car faster. With P=F/A, increasing the tire's pressure would increase the F (which I thought woud be fricitonal force) and offset the fact that you used a tire with reduced friction coefficients. Can anyone explain why my reasoning is incorrect?

 

[SuperSneaky24]

Verbal AAMC 7 R
114. Former low level employees who secure managerial positions in their company get more sophisticated equipment and more work related training than they had before. What relationships to info provided in the passage does this fact most plausibly suggest?

a) It supports the conclusion that occupational preparation and access to training are complementary
b) It opposes the assertion that power is shared in firms committed to training of employees
c) It exemplifies that inequities that exist in firms that are unable to follow the high road
d) It helps to explain the increasing disparity in earnings between management and workers.

Why is the answer choice c? I don't see any evidence fort this

I didn't like this question at all one bit. This wasn't included in the 40 question version however. Anyways, I chose A due to the same reasoning that you had, that C wasn't in the passage at all. However, looking back, I realized they wanted you to connect a ton of ideas together, which isn't very AAMC-like (usually it's the most straightfoward answer).

Anyways, at the end of the first paragraph, it says the low-road approach will limit income equity if if becomes the norm. THEN, you connect the idea that those with computer-based jobs earn more than those that don't. THEN you connect the idea that "Workers who receive formal company training command higher wages than do similar workers who attend only vocational school or receive informal on-the-job instruction" and you finally get answer C. Like I said, I was a little angry that they asked such a question, as the phrase "income equity" was said in the first paragraph, and the concept was never clearly brought up in the context of this question agian.

 

[SKation]

The passage straight out tells you that reaction 2 is faster than reaction 1. Increasing repulsion and/or reducing attraction (answers B, C, and D) are not consistent with the passage information that reaction 2 is faster. Answer A is the only valid option.

Hey,

I see that increasing the repulsion will not help the reaction however if we decrease the attraction between the chlorine and oxygen then wouldnt that allow for the oxygen to be more prone to leave?

Thanks1

 

[SuperSneaky24]

Hey,

I see that increasing the repulsion will not help the reaction however if we decrease the attraction between the chlorine and oxygen then wouldnt that allow for the oxygen to be more prone to leave?

Thanks1

My guess is that intramolecular attraction is not decreased when you protonate the oxygen, but rather the intramolecular attraction is increased. In the anion form, oxygen has an extra pair of electrons that repels that of chlorine. However, when you protonate the oxygen, it now has one less pair of electrons (now shared with hydrogen). Therefore, chlorine would be drawn in closer to oxygen, reducing the bond length.

 

[SKation]

Hey guys thanks for all the help so far. I was wondering if someone can provide a better explanation to question 42 as I still cannot seem to understand the answer explanation.

Item 42

Before the Landers quake, coincidence was argued as a sufficient explanation for what is now believed to be triggered-quake events. For these earlier events, which of the following does NOT support the coincidence hypothesis?

A The timing of subsequent quakes provided ambiguous evidence.

B Generally, the distances to the subsequent quakes was excessive.

C Too few of the subsequent quakes were recorded to establish a clear connection.

D Generally, the subsequent quakes were scattered in all directions.
Since we would expect the quake information to propagate in all directions, it does not support the coincidence hypothesis to learn that subsequent quakes occurred in all directions. The other three answers all stress the possibility of coincidence.

For this question could someone please show me how they derived (d2/d1)^3? Thanks.

Item 43

Solution
What is the ratio of lasting deformations produced by a quake at 16 L from its center to those produced at 4 L from its center?

A 1/16

B 1/32

C 1/64
Lasting deformations go as (L/d)3 according to the passage. Thus for two different values of d, d1 and d2, the ratio of lasting deformations will go as (d2/d1)3. This value will be (4/16)3 = (1/4)3 = 1/64. This is answer C.

D 1/128

138

If the signaling interaction at the two-cell stage involves protein, then how could the actinomycin-treated embryo develop normally? If mRNA synthesis is inhibited then where exactly will the required protein come from? The oleosome ?

Thank you so much guys!

Hey!,
I was having the same problem with the first two questions, did you get any proper explanation in order to be able to understand them?
Thanks!

 

[Skizye]

Question 98

Why is the alcohol more polar than the ketone? I thought the resonance form of the ketone would lead it to be more polar.
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I got this response

"Because OH allows it to hydrogen bond.
The ketone is thermodynamically favored because it doesn't have separation of charge, so don't count on its resonance form to make a significant contribution to its polarity."

Does hydrogen bonding influence polarity?

 

[sillyjoe]

For the VR section, passage 1, question 1... I originally had choice C but changed it because of the word "judgement". Can someone explain what they mean by human judgement? I thought it was the actions that humans were taking, not their judging of those actions.

 

[IslandStyle808]

For the VR section, passage 1, question 1... I originally had choice C but changed it because of the word "judgement". Can someone explain what they mean by human judgement? I thought it was the actions that humans were taking, not their judging of those actions.

There a three things I have learned about the verbal section that are very important
1) Look at the forest first before the trees - I don't just mean the central thesis of the passage, but also the answer as a whole and not just the sum of their parts
2) The thesis isn't always in the beginning passage
3) Knowing the wrong answers are as important as know the right one

You probably already know these three things and are doing much better on the verbal section than myself, but these three things are very important in tackling this particular question.

Alright on to the question. Don't be too critical about certain words because the MCAT writers love to make words that don't seem correct by themselves. However, if you take step back and look and think about the central theme and the answer choice as a whole you will see that it is true. So the central theme is that "humans make changes to the environment, some of which are detrimental, but this change is normal."

Of the answer choices you looked at, there are two. The first is A that "biodiversity is essential for survival" and the other choice is C "changes brought upon by human judgement are natural." Since C is bogging you down, eliminate A instead. The main message has nothing to do with biodiversity and its benefits to humans. They use biodiversity to introduce the real discussion, which is about human beings being a plague to this world (the bulk majority of the conversation is about this and biodiversity a minor thing). So this goes back to point two, the thesis isn't always in the beginning of the passage.

So looking at choice C it seems most plausible. When they mean "human judgement," they are just referring to human decisions or human choices. This leads to the first point I made which is about looking at the forest from the trees. When you look at the choice, look at it as a whole and don't get bogged down by certain words not really correctly used. Sometimes I like to put the answer choice in my own words before I choose my answers, because they look ambiguous when I look at them in detail.

Well I hope this helps.

 

[sillyjoe]

There a three things I have learned about the verbal section that are very important
1) Look at the forest first before the trees - I don't just mean the central thesis of the passage, but also the answer as a whole and not just the sum of their parts
2) The thesis isn't always in the beginning passage
3) Knowing the wrong answers are as important as know the right one

You probably already know these three things and are doing much better on the verbal section than myself, but these three things are very important in tackling this particular question.

Alright on to the question. Don't be too critical about certain words because the MCAT writers love to make words that don't seem correct by themselves. However, if you take step back and look and think about the central theme and the answer choice as a whole you will see that it is true. So the central theme is that "humans make changes to the environment, some of which are detrimental, but this change is normal."

Of the answer choices you looked at, there are two. The first is A that "biodiversity is essential for survival" and the other choice is C "changes brought upon by human judgement are natural." Since C is bogging you down, eliminate A instead. The main message has nothing to do with biodiversity and its benefits to humans. They use biodiversity to introduce the real discussion, which is about human beings being a plague to this world (the bulk majority of the conversation is about this and biodiversity a minor thing). So this goes back to point two, the thesis isn't always in the beginning of the passage.

So looking at choice C it seems most plausible. When they mean "human judgement," they are just referring to human decisions or human choices. This leads to the first point I made which is about looking at the forest from the trees. When you look at the choice, look at it as a whole and don't get bogged down by certain words not really correctly used. Sometimes I like to put the answer choice in my own words before I choose my answers, because they look ambiguous when I look at them in detail.

Well I hope this helps.

Certainly does. Thanks brotha

 

[RiPSTONE]

i still don't buy this answer
D is consistent with the passage as it states

"HOCl allows the oxygen transfer to take place more quickly because the hydrogen atom reduces the carge on the oxygen atom, facilitating the breaking of the O-Cl blond."

aaaaaahhhhhhh but i think i have the correct reasoning now

the reason A is a better choice is that the next sentence states

"Reaction 2 is first order in both NO2 - and HOCl" meaning it has 2nd order kinetics and hence is associative hence it has to do w/ the reactants associating together

I don't understand your "reasoning" what do you mean by associative meaning that it has to do with the reactants???