AAMC CBT6 and 6R OFFICIAL Q&A

[Vihsadas]

This is the official Q&A thread for AAMC CBT6 and 6R.

Please post ONLY questions pertaining to AAMC CBT6 and 6R.
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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[Fletcher Moore]

Thanks for the response. You must have had one hell of a PS, because it seems like most people's problems with AAMC6 was the PS. I'm kind of hoping there's going to be a more generous curve on the real thing. I got 34/40 on verbal on this one and it was an 11? That seems a little steep.

Looking over my scores, my PS for PT 6 was a point above my average on the PTs. So I ended up with a point below my average on the real thing. I tend to make a math error every single time I have to do a calculation (it feels), and I only had 2 hours of sleep before my 2008 test. So it is likely my fault more than test difficulty.

I would wager if you do all 8 PTs and determine the median scores for each section you can expect to score within a point of that. And I think it is definitely worth it to purchase and do all of the e-mcat PTs under test-like conditions. That is, at the same time of day as your test, working straight through timed only using the 10 minute breaks it gives you.

 

[moose45]

Anyone know the answer to PS Q48?

 

[lilmoomoobean]

What is the alternative to Sexual Reproduction?

A) Isogamy
B) Hermaphroditism
C) Pseudohermaphroditism
D) Parthenogenesis ** Correct answer


First of all what is he question asking? What do they mean by "alternative"? Alternative as in another way to reproduce sexually? This may seem like an easy question or maybe im thinking too much into it. Can someoen clarify what it is asking

Isogamy is a type of sexual reproduction which the gametes are identical

Parthenogenesis is a type of AESEXUAL reproduction because meiosis is not involved...

So in a sense, are they looking for asexual reproduction as an "alternative" to sexual reproduction? or an alternative method of sexual reproduction...which would be Isogamy..

HELP...so confused at what the question is askin to the point of delirium...

 

[LaurenMCAT]

Anyone know the answer to PS Q48?

AAMC Test 6
Q#48 = C
intensity is reduced

 

[LaurenMCAT]

What is the alternative to Sexual Reproduction?

Asexual reproduction

Parthenogenesis is really cool: http://en.wikipedia.org/wiki/Parthenogenesis

No sperm, just a female. Offspring doesn't have paternal DNA!

Recently seen in sharks in captivity - http://news.bbc.co.uk/2/hi/6681793.stm

And yes...you might just be reading too much into the question. Don't sweat it...happens all the time!

 

[WhiteWashed]

Hey just curious as to how you guys are getting AAMC 6....e-mcat doesn't list that as being sold anymore.


If anyone is in the holiday spirit, i'm always looking for practice material!

 

[LaurenMCAT]

AAMC just removed Practice Test 6 from their list of available exams.

I know that some of my Kaplan students still have access to that one. In the future, it's going to be dropped to allow access to the new Practice Test 11.

 

[emericana]

I got this correct but I guessed (I always choose "B" when I do not know the answer lol).

Do not understand why increasing the length by 2 will double the area by 4.

it seems to me that since the equation is:

Delta L = FL/YA if you double L you should double A not increase A by 4?

AAMC's explanation in general makes no sense to me can someone explain this better? Thanks a million!

 

[emericana]

One more question.

Why is this SN2 and not SN1?

(CH3)3COK is a tertiary compound that will go SN1 no?

 

[WhiteWashed]

I got this correct but I guessed (I always choose "B" when I do not know the answer lol).

Do not understand why increasing the length by 2 will double the area by 4.

it seems to me that since the equation is:

Delta L = FL/YA if you double L you should double A not increase A by 4?

AAMC's explanation in general makes no sense to me can someone explain this better? Thanks a million!

Friend, rearrange this beast and you shall get your answer. F/A=Y DELTA L/L

DELTA L=FL/AY
A=PI*R^2

DELTA L=F*L/((PI*R^2)*Y)

DELTA L=F*2L/((PI* 2R^2)*Y)

THEREFORE, DELTA L=FL/((PI*2R*Y)

Delta L goes down by a factor of 2.

 

[WhiteWashed]

One more question.

Why is this SN2 and not SN1?

(CH3)3COK is a tertiary compound that will go SN1 no?

The substrate is a methyl halide...SN2 EVERY TIME!

a methyl carbocation is not stable

 

[MedChallenge]

If anyone still has CBT 6 or can help me with this problem (the passage isn't necessary here)...

17. A GPS radio signal travels slower through Earth's atmosphere than it travels through the vacuum of space primarily because:

B. Gravity is stronger in the atmosphere of space
D. the atmosphere has a larger index of refraction than the vacuum of space <---correct answer

I understand why D is correct, but can't B also be true? Because gravity is an "extra" force pulling the satellite in and altering its path and velocity in the direction its trying to go?

 

[loveoforganic]

I think you're reading a little too deeply (and wrongly as it so happens) into the question. The question is asking you to consider the effect of various things on EMR. Gravity has no effect on EMR, as EMR is massless. Done.

To address where you were going wrong after reading in too far - gravity depends only on mass and distance, nothing to do with the composition of the substance it "passes" through.

 

[MedChallenge]

Ah, thanks loveoforganic...always very helpful!

I think you're reading a little too deeply (and wrongly as it so happens) into the question. The question is asking you to consider the effect of various things on EMR. Gravity has no effect on EMR, as EMR is massless. Done.

To address where you were going wrong after reading in too far - gravity depends only on mass and distance, nothing to do with the composition of the substance it "passes" through.

 

[MedChallenge]

For BS #125, could someone please explain why LDA causes an enolate to be formed? does it deprotonate completely? I thought it would only deprotonate the H from the -COOH group. Also, why does the pi bond act as a nucleophile instead of the two (more basic?) oxygens?

 

[MedChallenge]

Anyone?

For BS #125, could someone please explain why LDA causes an enolate to be formed? does it deprotonate completely? I thought it would only deprotonate the H from the -COOH group. Also, why does the pi bond act as a nucleophile instead of the two (more basic?) oxygens?

 

[loveoforganic]

LDA conjugate acid - pKa in the 30's.

Alpha proton pKa (for a ketone) - under 20.

I don't remember exactly how carboxylate alpha protons compare, but I would think it reasonable to assume pKa <30's

 

[mikexima]

can anyone explain question #30 in physics section for me? I dont have the explanations. its the one about the inernal energy of spring system

 

[kabtq9s]

A person suffering an asthmatic attack often has more difficulty exhaling than inhaling; the action of leukotrienes on bronchial smooth muscle contributes to this difficulty. As a result, what primary effect do leukotrienes have on lung gas exchange?

A) No effect, because bronchial smooth muscle is not found on alveoli
B) An increased accumulation of O2, leading to respiratory acidosis
C) An increased accumulation of CO2, leading to respiratory acidosis
D) A decreased intake of O2, leading to metabolic acidosis

Answer: C


OK, I understand there would be an accumulation of CO2 leading to respiratory acidosis, but the question italicizes PRIMARY. How is the the constriction of bronchial smooth muscle leading to an accumulation of CO2 a primary effect on lung gas exchange? Isn't that a secondary effect? I'd think a primary effect on lung gas exchange would be something directly affecting the diffusion of gasses between the alveoli and capillaries.

That's exactly what C says.

I dont get this either. How does an increase in O2 increase acidosis. I always thought CO2 would make the blood more acidic not O2.

Any comment is appreciated

EDIT: nvm I figured it out

 

[Hershi]

is there any way to get a hold of the key? i have a printed copy of the exam from when i had access to the exam but now it no longer shows up and i dont have the correct answers.

 

[psychkub]

"Which of the following changes would NOT interfere with the repeated transmission of an impulse at the vertebrate nueromuscular junction?"
a) Addition of a cholinesterase blocker
b) Addition of a toxin that blocks the release of acetylcholine
c) An increase in acetylcholine receptor sites on the motor end plate
d) Addition of a substance that binds to acetylcholine receptor sites

So I chose answer choice C (which is the correct one), but I don't quite understand why it cant be answer choice A. The Kaplan/AAMC explanations aren't really sufficient in my opinion. A cholinesterase blocker would mean that less acetylcholine is degraded and so its concentration in the neuromuscular junction would build up. With an increased NTMT concentration I would imagine that the chance of it synapsing on an acetylcholine receptor site would be higher and this would consequently happen at a higher rate. Thus, an impulse is more likely to be transmitted across the synapse and so will "not interfere with repeated transmission". Answer choice C also works because it would also increase the likelihood of a NTMT binding to a receptor site and lead to transmission of the impulse. B and D are certainly wrong because they are the opposite of what is needed. SOOOO can someone please explain why answer choice A MUST be eliminated?

I got this question wrong because I chose A instead of C. Can anyone provide an explanation why A is incorrect? Or is this just a case of C being the BEST answer for the question?

 

[psychkub]

BS # 143


BS #146

Bone components?? Bone is composed of Hydroxyapatite which has PO4 Ca & OH. damn what else do we need to know about bones. Seems like my kaplan review is lacking some details.

Pretty much, KAPLAN's Bio review states: "...while inorganic components include calcium, phosphate, and hydroxide (which combine and harden to form hydroxyapatite crystals), as well as sodium, POTASSIUM, and magnesium ions."

needless to say, I got this question wrong.

 

[JRGhatt]

#34. By what factor would a string's tension need to be changed to raise its fundamental frequency by a perfect fifth?

The passage states that each string is separated by a perfect fifth, a factor of 2/3.

equation given: f = [(Tension/density)^1/2] / (2L)

I don't understand how they got to 9/4. can someone help?

 

[Sports Junky]

#34. By what factor would a string's tension need to be changed to raise its fundamental frequency by a perfect fifth?

The passage states that each string is separated by a perfect fifth, a factor of 2/3.

equation given: f = [(Tension/density)^1/2] / (2L)

I don't understand how they got to 9/4. can someone help?

In order to increase the fundamental frequency by a perfect fifth, you would need to increase frequency by 3/2. The equation can be re-arranged to the following: F^2 = T. Therefore if you increase frequency by 3/2, then Tension must have increased by 9/4.

P.S. I eliminated the other variables from the equation because we assume they are not changed.

 

[Braindamage]

Can someone take the time to check for me which passages have been omitted from the old/100minutes 6R exam to make the new 52 question exam? There are 11 passages on the one I have with the following topics. Just tell me which topics aren't on the exam anymore. Thank you!

Passage 1: Archaebacteria
Passage 2: Periodic table trends
Passage 3: GPS and Sattelite Radio Ranging
Passage 4: Olestra/Sucrose Polyester
Passage 5: Corrosion of Silver coins
Passage 6: Stringed instruments
Passage 7: Thermal motion of atoms in solids
Passage 8: Inorganic compounds with ring systems
Passage 9: Comet orbiting around the sun
Passage 10: Solubility product: PbI2
Passage 11: Measuring Different nuclear isotopes in a sample

 

[drillers]

Oops, I thought since the AAMC 6 is no longer available that this thread didn't exist... my bad, anyways:

Scientists are most likely to find which compound listed in Table 1 in an alkaline lake?
NaCl, Ch3OH, H2SO4, or KOH

1. My initial thought was alkaline lake so there must be more OH- which is being provided by KOH

2. But then I thought ahaaaa, maybe this has to do with solubility where a more acidic compound is going to be more soluble in this alkaline lake

Ultimately I went with my second thought which was wrong. The correct answer is KOH not H2SO4.

I totally get how KOH is correct, but any thoughts on how to differentiate between KOH and H2SO4?

 

[Temperature101]

Oops, I thought since the AAMC 6 is no longer available that this thread didn't exist... my bad, anyways:

Scientists are most likely to find which compound listed in Table 1 in an alkaline lake?
NaCl, Ch3OH, H2SO4, or KOH

1. My initial thought was alkaline lake so there must be more OH- which is being provided by KOH

2. But then I thought ahaaaa, maybe this has to do with solubility where a more acidic compound is going to be more soluble in this alkaline lake

Ultimately I went with my second thought which was wrong. The correct answer is KOH not H2SO4.

I totally get how KOH is correct, but any thoughts on how to differentiate between KOH and H2SO4?

Alkaline is synonym to basic or having a pH greater than 7. KOH is a base and H2SO4 is an acid... I think that question was testing vocabulary... I don't how else I can explain that answer.

 

[keikoblue2]

In order to increase the fundamental frequency by a perfect fifth, you would need to increase frequency by 3/2. The equation can be re-arranged to the following: F^2 = T. Therefore if you increase frequency by 3/2, then Tension must have increased by 9/4.

P.S. I eliminated the other variables from the equation because we assume they are not changed.

I don't understand this explanation Tones separated by a perfect fifth
differ in frequency by a factor of 2/3, so why do we need to increase frequency by 3/2, instead of 2/3?

 

[pinklefluff]

For BS #125, could someone please explain why LDA causes an enolate to be formed? does it deprotonate completely? I thought it would only deprotonate the H from the -COOH group. Also, why does the pi bond act as a nucleophile instead of the two (more basic?) oxygens?

I'm also very confused about this and the mechanism of this reaction

 

[pinklefluff]

Hey guys,

I'm having trouble understanding for #206 why t-butanol is the best solvent to use.

The question is: if factors as competing side reactions and recovery of the product are considered, which of the following compounds is the best solvent for the synthesis.

The answer as explained by the princeton review explains how t-butanol would prevent a side reaction in student 2's reactions but what about student 1's?

Thanks!

 

[JingleChips]

Hey guys,

I'm having trouble understanding for #206 why t-butanol is the best solvent to use.

The question is: if factors as competing side reactions and recovery of the product are considered, which of the following compounds is the best solvent for the synthesis.

The answer as explained by the princeton review explains how t-butanol would prevent a side reaction in student 2's reactions but what about student 1's?

Thanks!

The passage states "Student 1's synthesis would yield an alcohol and alkene instead of the desired product" while the question is referring to the reaction mentioned in the passage, the SYNTHESIS OF TBME, which is accomplished successfully by student 2's reaction.

My thoughts about the exam in general...
I just finished with this exam (6R), and it was my best so far out of 3R/4R/5R/6R!

PHYSICAL - All I can say is screw that comet passage, it was the sole reason I didn't get a 15. A little ranting about one of those questions

59. Because comets shine predominantly by reflected sunlight, what one sees when viewing a comet is:
A. Coma Gas
B. Coma Dust
C. Tail Gas
D. Ice

The passage says

"Comets become visible to the unaided eye when, under the influence of radiation and the steady outstreaming of ionized hydrogen from the sun, the coma forms and extends into a vast, long tail of gas and dust.

I saw tail in the answer, and picked tail gas. Gases are also visible to the eye, so its not just dust causing the reflections.

VERBAL - After finishing I thought this was my worst verbal ever, but it ended up being my best verbal ever! I've gotten consistent 9's on the past AAMC R's but somehow pulled a 10 here! Its making me more relieved about verbal on the real deal.

BIO - This bio was much easier to me than AAMC 5R. One question away from a 14.

I'm sick of taking these damn practice exams and just want this whole thing to be over with. T minus 10 days!

 

[pacer]

Can someone explain Q13 (OLD 6R test)?

I see how they have calculated the distance in the solution but I am confused why my method iswrong.

Satellite is at 40 degree from horizon
it takes 0.07 seconds for the signal to reach
Horizontal distance = radius of earth + distance above earth where the satellite is orbiting = 4.2 x 10^7m

why can't we use this information with trig to calculate the distance?

cos 40 = horizontal distance/hypotenuse distance

 

[pacer]

Q 72

I know that Pb(OH)2 is a base and would be soluble in acid BUT isn't there a solubility rule that states that Pb, Ag, Hg are insoluble except in nitrate, acetate or perchlorate forms.

Then why is B the right answer?

How do we determine that CaF2 has no preference for either solution?

 

[pacer]

Q178 - Isn't reabsorption of filtrate dependent on pressure? Why is B wrong?