AAMC CBT10 only OFFICIAL Q&A

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This is the official Q&A thread for AAMC CBT10.

Please post ONLY questions pertaining to AAMC CBT10.
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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Oxidative phosphorylation is the ETC. The ETC gradually takes the energy from the electron as it passes through; it uses this energy to pump H+ into the intermembrane space. The electrochemical gradient that is set up by this causes the H+ ions to enter back into the matrix through the ATP synthase protein; this protein has a spinning head phosphorylates ADP by harnessing the energy released by H+ moving down its gradient.

Thanks for the reply!

So let me get this straight...It pumps H+ into the intermembrane space in order to create a shortage of H+ in the matrix? And so when the H+ diffuses back down its gradient and into the matrix, it makes ATP b/c the energy/force that is released as it moves down its gradient helps to phosphorylate the ADP to ATP?

B/c on AAMC 10, BS: #100 I don't fully understand why "diffusion of H+ through the inner mitochondrial membrane will affect proper ATP production"

can anyone explain how so, to me?

Thanks for the help!:D
 
Thanks for the reply!

So let me get this straight...It pumps H+ into the intermembrane space in order to create a shortage of H+ in the matrix? And so when the H+ diffuses back down its gradient and into the matrix, it makes ATP b/c the energy/force that is released as it moves down its gradient helps to phosphorylate the ADP to ATP?

B/c on AAMC 10, BS: #100 I don't fully understand why "diffusion of H+ through the inner mitochondrial membrane will affect proper ATP production"

can anyone explain how so, to me?

Thanks for the help!:D

Yeah because as the ETC continues, H+ is pumped to the intermembrane space. With such a high concentration in the IMS and a low concentration in the Matrix, the H+ will flow from high concentration to low concentration down the concentration gradient through ATPsynthase. thus yes, adding a phosphate group to ADP.
 
B/c on AAMC 10, BS: #100 I don't fully understand why "diffusion of H+ through the inner mitochondrial membrane will affect proper ATP production"

can anyone explain how so, to me?

Thanks for the help!:D

Yes, it it is definitely C,

EVEN if you know a bit about This catabolic pathway, you should easily be able to take a, b and d out of the runnign for they surely dont affect the diffusion of H+ to produce ATP
 
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Yeah because as the ETC continues, H+ is pumped to the intermembrane space. With such a high concentration in the IMS and a low concentration in the Matrix, the H+ will flow from high concentration to low concentration down the concentration gradient through ATPsynthase. thus yes, adding a phosphate group to ADP.

Thanks but still why will the diffusion of H+ through the IMS result in few/no ATP production? I'm talking about AAMC 10 BS: #100:confused:
 
Yes, it it is definitely C,

EVEN if you know a bit about This catabolic pathway, you should easily be able to take a, b and d out of the runnign for they surely dont affect the diffusion of H+ to produce ATP

Thanks again lol, but like what is the reasoning as to why C is correct, I wasn't able to do process of elimination during the exam and so I just picked A b/c I saw the Inner Mitochondrial part in there, but so what happens if you INCREASE the diffusion of H+ through Inner membrane, won't that just make MORE ATP?
 
Thanks but still why will the diffusion of H+ through the IMS result in few/no ATP production? I'm talking about AAMC 10 BS: #100:confused:

What the question is saying is that if DDT were to cause these accumulated H+ ions in the intermembrane space to diffuse out, (not through ATPase) what would happen?

Well, the concentration would change in the intermembrane space, causing less to go through ATPase and produce ATP.

thus, less H+ in intermembrane space, causes less diffusion through ATPase, and thus less ATP
 
Thanks again lol, but like what is the reasoning as to why C is correct, I wasn't able to do process of elimination during the exam and so I just picked A b/c I saw the Inner Mitochondrial part in there, but so what happens if you INCREASE the diffusion of H+ through Inner membrane, won't that just make MORE ATP?

Haha we are one step ahead of each other.

IF you increase the H+ concentration in the IMS, and let it diffuse through the APTase, then yes MORE ATP.

But, yeah the question was written bad, they want you to see waht happens if it diffuses else where, thus lowering the H+ concentration=
 
Haha we are one step ahead of each other.

IF you increase the H+ concentration in the IMS, and let it diffuse through the APTase, then yes MORE ATP.

But, yeah the question was written bad, they want you to see waht happens if it diffuses else where, thus lowering the H+ concentration=

Ohhhhh! so the question is asking/saying pretty much, the H+ in the IMS has been reduced it diffuses somewhere else somehow (not through the ATPase channels, and so with LESS H+ TO PUSH BACK INTO THE MATRIX, w/out the use of ATPase (also) there will be LESS ATP made b/c there is less H+

right?

and thanks again for your help and patience:cool:
 
Ohhhhh! so the question is asking/saying pretty much, the H+ in the IMS has been reduced it diffuses somewhere else somehow (not through the ATPase channels, and so with LESS H+ TO PUSH BACK INTO THE MATRIX, w/out the use of ATPase (also) there will be LESS ATP made b/c there is less H+

right?

and thanks again for your help and patience:cool:

hahaha exactly! good job! and no problem!
 
I can't believe I'm the first to ask this....But did anyone know what a vole was!??! That seemed like a cheap shot.

Definitely a cheap shot - got it right on a guess after elimination. I actually forgot the choices (snake, rat, ..??) and what the correct answer was... what a useless piece of information.
 
I got #47 on BS right, but having a hard time comprehending the main point of the explanation given. My reasoning - Is the alpha particle able to produce the largest anode signal because it has more electrons to loose?
 
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I got #47 on BS right, but having a hard time comprehending the main point of the explanation given. My reasoning - Is the alpha particle able to produce the largest anode signal because it has more electrons to loose?

I did not look up the question/passage for you, but I think I remember it. The reason the alpha particle is the best choice is because it has a 2+ charge; the other particles either had a single charge (like H+ or an electron) or no charge at all (ex. a noble gas, probably He).

More charge elicits a greater signal.
 
I don't understand how the alpha particle has a 2+ charge. I thought it was the equivalent of a helium atom, which is neutral.

Can someone explain this for me please?
 
I don't understand how the alpha particle has a 2+ charge. I thought it was the equivalent of a helium atom, which is neutral.

Can someone explain this for me please?

Therein lies the problem - you don't know what an alpha particle is. It's atomic mass can be considered essentially the same as a helium atom, but that's about it.

The simplest definition of an alpha particle is a helium nucleus (a helium atom stripped of its electrons).
 
Hey guys, please remember not to mention the questions/answers of specific AAMC practice CBTs in any other thread than the official thread made for that exam. Here you discussed specific questions in CBT10 and it would be a real shame if one of your peers accidentally clicked on this thread and saw the answer before they even took the practice exam! Try to keep those specifics to the threads for each test so that you don't spoil practice exams for your peers.
http://forums.studentdoctor.net/showthread.php?t=516243

***What is written above was originally part of a thread separate from this AAMC CBT10 thread.
Merging this thread with the AAMC CBT 10 thread.
Thanks and good luck on your MCAT. :)
 
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Be wary that there is a mistake on #54 in the Verbal section. They highlighted the wrong answer as correct.

The question asks "Dort Mentions sink holes in order to:"
choice A's explanation says: "The elimination of an alternate hypothesis is the reason for the reference to sinkholes..." As a result this answer is obviously the correct one. Yet they highlight B as the answer when B's explanation is saying that B is not the answer.


yay. my 5 gets moved up to a 6. this is pretty discouraging considering that the test is in 3 days... im uber worried now:scared:
 
This is why I tend not to follow people's opinions on exam difficulty. I thought VR for 10 was the easiest out of all from 6-10. I've been the opposite for almost every test in terms of my opinion on difficulty. I'm just going to stop trolling the june 13th thread and study more.

adios

good luck

and may the force be with you. always.
 
For PS#45, how do I know that C is better than A? I recognized that C was true, but I figured if you are shooting a particle into these machines, then you'd probably know what particle you're shooting. That, and I thought identifying what particle you're shooting was too far from the main purpose of the passage.
 
For PS#45, how do I know that C is better than A? I recognized that C was true, but I figured if you are shooting a particle into these machines, then you'd probably know what particle you're shooting. That, and I thought identifying what particle you're shooting was too far from the main purpose of the passage.
I honestly had the worst luck with this passage and had to guess on a couple but this was one I should have gotten because I knew what they were going for. The machines are analyzing intrinsic properties of the particle in question. More time to analyze the sample isn't something of a concern for them (I'm guessing that it's because everything happens so fast in general that time isn't a constraint they can really vary) because it doesn't help as much in defining the particle as, say, curving the trajectory.
Think about it this way
A charge moving through a magnetic field is pushed by a force (F), which causes the particle to curve either in one or the other direction based upon the direction of the current. This Force is the same force we find out using the right hand rule and can actually be considered a centripetal force on the object. Thus: F = Mv^2/r = qvB. From this, we can see how the radius of curvature is an excellent way of figuring out the particle because each particle will have a differing radius of curvature based upon each particles properties (charge, mass, etc).

One final thing; although time MAY be helpful, the question still asks which is the best. I hate these questions as much as the next person, but the question specifically asks for the curvature and if you remember that above equation it can help a lot in understanding that. Not to mention, it helps you see that the force doesn't do any work on the particle in question, but is instead a centripetal force in a magnetic field.


- edit -

Sorry for that, I completely mistook your question. Let me answer your REAL question. The passage states that these accelerators are used to examine the properties of the particles emerging from the collisions, thus, they do not know what the particles are. Thus, using something like radius of curvature in the above would help in determining the charge and mass of particles, which would help in saying what each particle is. And you're not "shooting" a particle, the particle is accelerated from a collision. You're measuring the after effects of the collision. So the particle may be known beforehand, but the aim is to determine what comes out of the collision.

- edit -

What the hell; I thought cathodes attracted electrons? Why does it say that the electrons are accelerated to the anode?
 
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BS #130 -- I thought counterclockwise was S configuration, not R. Am I wrong?
 
BS #130 -- I thought counterclockwise was S configuration, not R. Am I wrong?
You're right. R is right, S is left. I don't know why they had that screwed up. You'd think they would have a reviewer for stuff like this.:thumbdown:
 
BS #130 -- I thought counterclockwise was S configuration, not R. Am I wrong?

The explanation (possibly poorly worded) did not say counterclockwise is R, it only said "groups ..... oriented in a counterclockwise direction with the group of lowest priority (H) pointed out. This is the R configuration"
What was missing in the explanation was since H is pointing out, the configuration has to be inverted and so it is R.
 
OK, I just finished the AAMC 10 and there was a question on the Bio section about "voles." I was like, WTF, what is that?? (They are mice-related.) Is there a lot of random crap knowledge like this on the real MCAT? I feel I am at a particular disadvantage because English is not my native language.

Oh, and "voles" were not defined in the passage nor was there anything in the passage that could allow you to infer what it was.
 
OK, I just finished the AAMC 10 and there was a question on the Bio section about "voles." I was like, WTF, what is that?? (They are mice-related.) Is there a lot of random crap knowledge like this on the real MCAT? I feel I am at a particular disadvantage because English is not my native language.

Oh, and "voles" were not defined in the passage nor was there anything in the passage that could allow you to infer what it was.

i distinctively rememer that question b/c it was so stupid. ive never come across any other question like that (i took the real deal 5/27). i think they were going for a question on taxonomy....but it was just dumb. dont sweat it.
 
Thanks Visahdas. I should have done a search, sorry.

OK, This might be seem to be a very stupid question to some of you, so I apologize in advance.

So my question is... how were we supposed to know that the projectile falls? I mean, I know in real life, once a projectile is launched, it has to come down eventually, but in this passage, it is never specifically mentioned. It only talks about launching it and the height attained. The question wording especially made me choose C, because I thought we were considering only the first half of the projectile motion.

Also, I don't really understand why the frequency shift decreases to zero. I mean, I know that the frequency decreases when the detector and the source are getting further away from each other, but how would we know it goes to zero?
 
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When the projectile is at the apex of its flight its velocity is zero with respect to the observer. That means, given the following equation:

Δf/f₀ = v/c where v = relative difference in velocity and c is the speed of the wave in the medium that the Δf (or frequency shift) is zero.

As for the first question, it was very irritating how they worded that question. It took a leap of faith to determine whether or not they were talking about a projectile through its "entire" path or until the point it hit its apex. But, if I remember right only one question mentioned that the frequency shift dropped to zero, so that could be the only correct answer.
 
OK, I just finished the AAMC 10 and there was a question on the Bio section about "voles." I was like, WTF, what is that?? (They are mice-related.) Is there a lot of random crap knowledge like this on the real MCAT? I feel I am at a particular disadvantage because English is not my native language.

Oh, and "voles" were not defined in the passage nor was there anything in the passage that could allow you to infer what it was.
I'm not sure it was "entirely" random crap knowledge, I just think the answer to the question was very bad. I think that rodents were the only good option b/c the passages was about a "virus", which infects animals by recognizing cellular receptors and then being endocytosed. We know humans weren't the correct answer b/c the passage was about humans being infected. You can easily reason that the two reptiles being questioned were less likely than a rodent b/c of the fact that we are so taxonomically removed (meaning we probably have very different cell receptors) from reptiles and therefore its very unlikely that a virus infecting reptiles would infect humans, especially given the option of a mammal.
 
thanks, tncekm. Your explanation of the freq shift made so much sense.

And you're right. I guess you could have inferred that it had to be voles from the psg... oh, how I wish I had your deductive skills. I just freaked out when I saw the the word voles.
 
thanks, tncekm. Your explanation of the freq shift made so much sense.

And you're right. I guess you could have inferred that it had to be voles from the psg... oh, how I wish I had your deductive skills. I just freaked out when I saw the the word voles.
Just practice and you'll get there :thumbup:
 
I know that nondividing cells go to the Go stage, but why G1 over G2? G1 and G2 are both growth phases and I don't understand why it's G2. Is it because you have to go through the S(active synthesis) phase to get to G2?
 
I know that nondividing cells go to the Go stage, but why G1 over G2? G1 and G2 are both growth phases and I don't understand why it's G2. Is it because you have to go through the S(active synthesis) phase to get to G2?
That was a tricky one to reason. However, if a cell is in G2 it has already been through S. If a cell has been through S it has duplicated everything, which means that its much more likely to be committed to completing mitosis. Therefore, the G1 stage is a more reasonable answer.
 
Why is [H3O+] = [oAC-] in the solution?
Also, how are you guys cutting and pasting these questions? The AAMC test application does not let me cut and paste from IE.
 
Why is [H3O+] = [oAC-] in the solution?
Also, how are you guys cutting and pasting these questions? The AAMC test application does not let me cut and paste from IE.

CH3COOH --> H+ + CH3COO-

When acetic acid dissociates, it becomes both a proton and the acetate ion. Both are formed, so their concentrations are the same.
 
Could someone please help me out with passage seven in PS? I haven't had a passage trip me up this bad and the scant explanations given in the solution don't really help. Specifically the multiwire proportional chamber lost me...below are the questions.

43)Is it possible for a single particle passing through a multiwire proportional chamber to initiate more than one anode signal?

A) No, because there would be only one ionization trail through the chamber
B) No, because only one electron cascade at a time is physically possible
C) Yes, if the applied voltage is sufficiently low
D) Yes, if the ionization trail is equidistant from more than one anode wire

This is a special case in which a charged particle (electron) can be equally detected by two anodes if the particle’s trail is equidistant between two adjacent anodes. There is no preference for one anode over another. Thus, D is the best answer.

44)The voltage in a proportional chamber is set to cause the electrons to cascade so that the:

A) distance between cathode and anode can be maximized.
B) signals produced at the anode will not be too weak to detect.
C) particle trajectories have enough time to exhibit curvature.
D) circuitry characteristics of the chamber are not affected by its shape.

The point of using cascading electrons is to amplify a signal, especially a weak one. Thus, B is the best answer.

46)The spatial resolution of stacked multiwire proportional chambers is determined by the:

A) applied voltage.
B) density of the ionizing gas.
C) density of particle tracks.
D) spacing of the anode wires.

Spatial resolution refers to the ability to locate an event in space. The closer the spacing of the anode wires, the better one can specify where an event took place—this is a limiting factor. Thus, D is the best answer.

Thanks for your help!
 
#54 in the verbal section, Kaplan actually says its a different answer and explains how AAMC has it wrong...haha
 
Does anyone know how closely the verbal on CBT 10 will compare with the difficulty level of the real exam?
 
For PS #20, regarding the magnitude of the frequency shift, the right answer is A which is it falls linearly to zero, then increases.

Isn't the frequency shift proportional to velocity, and since the object is decelerating, the shift shouldn't be linear? I picked C because I used that logic to rule out A, but I realize that frequency shift had to get to 0 at some point. I see that A is the best answer, but it seems to be false.
 
For PS #20, regarding the magnitude of the frequency shift, the right answer is A which is it falls linearly to zero, then increases.

Isn't the frequency shift proportional to velocity, and since the object is decelerating, the shift shouldn't be linear? I picked C because I used that logic to rule out A, but I realize that frequency shift had to get to 0 at some point. I see that A is the best answer, but it seems to be false.

delta f = (delta v)/(v_sound)

g = 10, so the slope of v is going to be a constant -10. This is a linear slope downard, so the relative velocity (delta v) is going to decrease to 0, when it reaches the apex. From there, it will descend and with a = g = 10, a positive linear slope. So you will observe a linear increase. Hope this helps.
 
Number 101 on BS,

Why is it fractional distillation? I thought that was meant for liquids that boil less that 25 degrees apart. However, 1-Propanol and 1,2-ethanediol differ by 100 degrees....??
 
i guess technically you could use fractional distillation for any liquids that boil at different temperatures..... if it works at less than 25 degrees apart, it should still work at 100 degrees apart
 
I don't understand how to do PS #15, any help in the right direction would be helpful. Thanks.
 
Two ways to do it...

1. You have memorized every lens/mirror situation and know that an object beyond the focal point of a convex lens forms a real, upside-down image.

OR

2. You can draw a ray diagram. These have 3 lines.

First line: Draw from the top of the object directly to the lens center line and then through the opposite focal point.
Second line: Draw from the top of the object through the midpoint of the lens.
Third line: Draw from the top of the object through the nearest focal point then to the center line of the lens then parallel with the horizontal plane.

Where these three line coincide is the tip of the image.
Here is a very poor diagram I made...
 

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