AAMC CBT10 only OFFICIAL Q&A

[Vihsadas]

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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[Phlame217]

Just know that the first scientists in real life to isolate the H. Pylori won the nobel prize for it by injesting it to prove his point. My bio professor always got a kick out of that.

BTW i just took my final test and got:

10PS
10VS
15BS

how bout them apples

 

[junkct]

Just know that the first scientists in real life to isolate the H. Pylori won the nobel prize for it by injesting it to prove his point. My bio professor always got a kick out of that.

BTW i just took my final test and got:

10PS
10VS
15BS

how bout them apples

VS? Verbal Sciences? 0_o

 

[alacast]

Firstly, does anyone else thing that AAMC has a tendency to give horrible explanations for some answers? Some of the physics ones amount to "Because C is correct", and I've seen at least one numerical typo.

With that said, item 53 on 10R seems to be particularly bad, and I just want to make sure I'm not misreading it.

Question:
"Dort mentions sinkholes in order:"

Answer A:
to eliminate an alternative hypothesis regarding the formation of the crater.

Rationale given by AAMC:
The elimination of an alternative hypothesis is the reason for the reference to sinkholes, with the explanation that “the rock formations aren’t the sort to collapse and form sinkholes.”

Answer B:
to impress the reader with the uniqueness of the discovery.

Rationale given by AAMC:
The reason Dort concluded that it could only be a meteorite crater is because the feature seemed “too exotic.” The inference is that the sinkhole would make the depression a less unique feature and thus require a more common explanation.

Both rationales say that their respective answers are correct, yes? Which one of these do you think AAMC marked as right? Does the MCAT have a history of such poor editing?

 

[sdguy2008]

Titrations, question 28. I think I'm missing something fundamental with this one. I don't understand the explanation that H30+ and OH- concentrations are equal at pH 7 as the answer to this question. I thought that acid=conj. base at 1/2 eq. pt. for a weak acid titrated with a strong base, as is the case here. So why is it saying acid=base at the eq. pt in this problem?

Again, I think it's something basic I'm messing up. Any clarification would be great. Thanks.

 

[loveoforganic]

Could you post the problem please?

 

[sdguy2008]

Yeah sorry about that. There is a titration curve (HCL=analyte and NaOH=titrant), and eq. pt. is at pH 7 obviously. Question asks:

The concentrations of H30+ and OH- ions are equal after approximately how much of the NaOH is added?

The answer happens to be 25 mL in this case.

I think I got mixed up and thought they were titrating acetic acid and NaOH, and that's why I thought acid=base at 1/2 eq. pt. I guess it's not the same when you are titrating strong acid with strong base?

I also would like a little clarification just to be sure what is exactly happening at the 1/2 eq pt and the eq pt for titrations of both strong acid/base and weak acid/strong base.

Thanks for any help.

 

[johnj7]

these questions are vague, and the only reason i got it right because i saw types like it before

i may not be 100% correct but it has to do with how they define the equivalence point and what the purpose of titrations in the first place are.

at the equivalence point you know for sure that the moles of base OH added are going to be exactly equal to the mols of acid you started off with aka H30+

thus their reasoning that -OH = H3O+

hopes that makes sense. it is confusing because they don't tell you word for word what they are referring to as "H30+"
the OH - = H30+ they are referring to is not the acid / conjugate base pair. the OH is the total base used to titrate, and the H3O+ is the amount of acid present at first

also you are right, at half eq point conjugate base = acid, but this question has to do with the eq point, not half eq point

 

[ksmi117]

To make this more simple and general... [H3O+] = [OH-] when ph = 7... always. [H3O+]*[OH-] = 10^-14 so when they are equal [H3O+]= 10^-7 -> pH = 7.

If you had been titrating a weak acid with NaOH, the volumes of the acid and base would not be equal (like in the problem on the practice test)when pH = 7, since the weak acid wouldn't contribute as many H+ ions to the solution and a strong acid at the same concentration would. pH = 7 would be whenever the amount of H+ at equilibrium = OH- added.

Does this make sense??

 

[sdguy2008]

Thanks john and ksmi.

I think you are right about the question being a bit vague, but I also admit I stink at titrations.

ksmi, just to clarify, if strong acid is titrated with strong base, the volumes of acid and base in the solution ARE equal when pH=7? but this is not the case with weak acid/strong base?

And one last thing. I think a big source of confusion for me with this is stemming from a problem I saw on titrations of polyprotic acids. Specifically titrating H2SO4 with NaOH. OK follow me for a sec: at the first equivalence pt for this titration, my chem book says all H2SO4 turns into the conjugate base HSO4-. Then in the buffer domain of the curve, [HSO4-]=[SO4-]. So in this case, why doesnt acid=base at the first eq. pt. like the problem we talked about above? It is a strong acid and strong base combo. Is it just different for polyprotic acids? In other words, are we interpreting the eq. pt. differently for a polyprotic titration than for a normal titration?

Sorry for all this blabbing guys, titrations will be the end of me. April 18th cant come soon enough.

 

[ksmi117]

Thanks john and ksmi.

I think you are right about the question being a bit vague, but I also admit I stink at titrations.

ksmi, just to clarify, if strong acid is titrated with strong base, the volumes of acid and base in the solution ARE equal when pH=7? but this is not the case with weak acid/strong base?

And one last thing. I think a big source of confusion for me with this is stemming from a problem I saw on titrations of polyprotic acids. Specifically titrating H2SO4 with NaOH. OK follow me for a sec: at the first equivalence pt for this titration, my chem book says all H2SO4 turns into the conjugate base HSO4-. Then in the buffer domain of the curve, [HSO4-]=[SO4-]. So in this case, why doesnt acid=base at the first eq. pt. like the problem we talked about above? It is a strong acid and strong base combo. Is it just different for polyprotic acids? In other words, are we interpreting the eq. pt. differently for a polyprotic titration than for a normal titration?

Sorry for all this blabbing guys, titrations will be the end of me. April 18th cant come soon enough.

Yes, this is correct, if they have the same concentration...

Can you try to explain your question again? I got lost at the bolded part...

 

[sdguy2008]

Yeah I figured it might be a little tough to follow. Let's try it this way:

Normal titration- at the equivalence point [acid]=[base]

Polyprotic titration- at the first equivalence point, all acid --> conjugate base (all H2SO4 turns into HSO4-). Why??

 

[ksmi117]

So say and acid is being titrated... so the base is the titrant (added to acid)... the equivalence point is when the concentration of acid = the concentration of the base that is added.

For example, titrating HCl with NaOH. The equivalence point is when [HCl] = [NaOH]. Not when [HCl] = [H+]. When there is exactly enough of each reactant so that HCl + NaOH -> H2O + NaCl.

In the case of a diprotic acid, H2SO4 and the titrant NaOH. The first equivalence point occurs when [acid] = [base]. When there is exactly enough of each reactant so that H2SO4 + NaOH -> NaHSO4 + H2O.

The second will occur when 2[acid] = [base]. When there is exactly enough so that H2SO4 + 2NaOH -> Na2SO4 + 2H2O.

So the first equivalence point is when all of the first H+ reacts and the second is when the 2nd H+ from each H2SO4 reacts...

Ok, I feel like I didn't explain this well... ask questions if this is the case, please!

 

[sdguy2008]

haha. i totally understand everything you just wrote, and it's exactly how I've been thinking about it. I'm just trying to understand why the equivalence point means something different for the two scenarios. For the first one you mentioned, [acid]=[base] at the first eq. pt. The acid doesn't all turn to base. For the polyprotic titration, at the equivalence point all the original acid turns into its conjugate base. Why?

i think i might just be way overthinking it, or trying to do too much. i want to be confident with titrations on this test because it's my weakest topic overall.

thanks again for all the help ksmi, it's ok if you want to give up on this, i know it can get annoying when you know what to do and someone else just isnt getting it.

 

[ksmi117]

So I'm not sure if you understand what I said... haha

So when I say [acid] = [base], I mean the concentration of the acid and the concentration of the titrant, not the acid and it's conjugate base.

 

[Vihsadas]

Hi!
Please remember to post the questions specific to the AAMC exams within the thread made specifically for that exam. See the "rules of order" thread at the top of the forum. Thanks!

 

[Vihsadas]

Hi! Please remember to post your questions about the official AAMC exams only in threads made for that specific purpose. Check out the stickied "Rules of Order" thread at the top of the forum. Thanks!

 

[metsfanmd]

It mentions a gray image in the second part of the answer... "The rays cross at the gray image shown..."

I'm wondering if only I can't see the image or if they're are eluding to an image that we are supposed to be imagining?

 

[carbonfishbone]

It mentions a gray image in the second part of the answer... "The rays cross at the gray image shown..."

I'm wondering if only I can't see the image or if they're are eluding to an image that we are supposed to be imagining?

Yep, I just looked at it through my laptop. It doesn't show for me either. I think there are a couple questions through out the AAMC tests that don't display in my browser.

I am not sure if you need help with this question but, Ill give it anyway

Berkeley Review uses the mnemonic UV:IR for lenses. Where if the image formed is Upright it will always be Virtual and if the image is Inverted, it will always be Real.

For a diverging lens, no matter where the object is (either inside or outside the focal length) the image will ALWAYS be virtual, and thus upright.
For a converging lens, if the image is outside the focal length the image will be Real, and thus inverted. However, if the object is inside the focal length the image formed will be virtual, and thus upright.

I suggest looking at these effects through a ray diagram; it should give you better intuition on how/why these results occur, rather than just memorize them.

 

[metsfanmd]

Yea I understood the question and why I got it wrong, but wanted to make sure I wasn't missing anything from my exam... plus that mnemonic looks pretty handy thanks.

 

[Corvette]

Yeah, I understand what you're saying about why A is wrong and why the ethics of C should be disregarded for this question, but sometimes the MCAT does actually throw stuff at you where an answer could be correct in principle, but not the correct answer for the mcat because it is inefficient or unethical or whatever. The fact that you have to disregard ethics for this question seems inconsistent to me and that's why it bugged me... and actually the answer choice says "healthy individuals and animals" so I think you're supposed to assume that the individuals are human...

This was the ONLY question I got wrong on the entire CBT 10 bio section. And I disregarded choice C on ethical grounds as well. The question says that the conclusion was demonstrated on proof that [answer goes here], and I feel like choice C was such an unlikely demonstration! Ugh.

Anyway, is it generally accepted that AAMC CBT 10 PS and BS is much easier than usual, while verbal is much harder than usual? This was my best PS (14) and BS (15) while my worst verbal (10)

 

[carbonfishbone]

Haha...

So I was going back and reviewing my verbal mistakes. Did anyone else on Verbal # 92, the last question, mistake the answer BAT as a baseball bat?

I probably should of realized that it meant the animal, but the word bat, DOES mean baseball bat AND flying animal. Damn cheap shoot, AAMC...

 

[CupcakeMD]

Firstly, does anyone else thing that AAMC has a tendency to give horrible explanations for some answers? Some of the physics ones amount to "Because C is correct", and I've seen at least one numerical typo.

With that said, item 53 on 10R seems to be particularly bad, and I just want to make sure I'm not misreading it.

Question:
"Dort mentions sinkholes in order:"

Answer A:
to eliminate an alternative hypothesis regarding the formation of the crater.

Rationale given by AAMC:
The elimination of an alternative hypothesis is the reason for the reference to sinkholes, with the explanation that “the rock formations aren’t the sort to collapse and form sinkholes.”

Answer B:
to impress the reader with the uniqueness of the discovery.

Rationale given by AAMC:
The reason Dort concluded that it could only be a meteorite crater is because the feature seemed “too exotic.” The inference is that the sinkhole would make the depression a less unique feature and thus require a more common explanation.

Both rationales say that their respective answers are correct, yes? Which one of these do you think AAMC marked as right? Does the MCAT have a history of such poor editing?

I agree. I had the same problem with this question.

 

[docbrill]

Yeah, I understand what you're saying about why A is wrong and why the ethics of C should be disregarded for this question, but sometimes the MCAT does actually throw stuff at you where an answer could be correct in principle, but not the correct answer for the mcat because it is inefficient or unethical or whatever. The fact that you have to disregard ethics for this question seems inconsistent to me and that's why it bugged me... and actually the answer choice says "healthy individuals and animals" so I think you're supposed to assume that the individuals are human...

I picked A for the EXACT same reason I thought choice C was unethical. I overthink the questions waaay too much!

 

[docbrill]

Could someone please explain the answer for #108 in BS:
If some but not all of the offspring from repeated mating of the same fruit flies show the recessive trait for vestigal wings (vv) and ebony color(ee), which of the following could have been the genotype of the individuals mate?
A: Both VvEe

Why can't it be one vvEE and one VVee??

Apparently, I suck at BIO because I got an 8 (got wrong only two questions from the o. chem part), and I am taking the exam on May 22!! I am so stressed, any advice? My composite was (PS11 VR8 BS8), and I am aiming for 30+. Is it possible concidering that my highest AAMC was 28?

 

[docbrill]

Anyone?

 

[Chowdder]

Could someone please explain the answer for #108 in BS:
If some but not all of the offspring from repeated mating of the same fruit flies show the recessive trait for vestigal wings (vv) and ebony color(ee), which of the following could have been the genotype of the individuals mate?
A: Both VvEe

Why can't it be one vvEE and one VVee??

Apparently, I suck at BIO because I got an 8 (got wrong only two questions from the o. chem part), and I am taking the exam on May 22!! I am so stressed, any advice? My composite was (PS11 VR8 BS8), and I am aiming for 30+. Is it possible concidering that my highest AAMC was 28?

The key words in the question is "same fruit flies" and "some but not all of the offsprings". This indicate that the same parents are producing the offsprings and that the recessive trait is being expressed in only a portion of the population. Parents of VvEe will give you that possibility because (assuming that the allels are not linked) the genotype will be inherited in a 9:3:3:1 manner. 1 out of 16 offsprings will express the recessive trait (ee and vv). Parents of vvEE will only be able to produce vE gametes and parents of VVee will only be able to produce Ve gametes. If these are fused, then the offsprings will only be VvEe, a heterozygote. Therefore, you can not get recessive trait expressed from these F0 generation pairs.

And to answer your original concern, yes it is possible to get 30 on the real thing. Many on SDN have done so even though their practices are in the mid 20s. Check this post if you need some reassurance.

Best of luck

 

[Chowdder]

Not sure if anyone else got this wrong.
124: The ELISA is a test that is often used to detect antibodies to a particular organism. Would a positive result from such a test for H. pylori indicate that the patient had an ulcer?

I was bogged down on this question and ended picking the wrong answer cause I figure that the statement is true because "had" implies that the patient had (past tense) contracted ulcer due to H. pylori infection. I wanted to find an answer that says something like "yes, because the patient could have been infected by H. pylori and recovered". Couldn't find it so I just went with C and moved on. Stupid wording...

 

[Zona Pellucida]

Not sure if anyone else got this wrong.
124: The ELISA is a test that is often used to detect antibodies to a particular organism. Would a positive result from such a test for H. pylori indicate that the patient had an ulcer?

I was bogged down on this question and ended picking the wrong answer cause I figure that the statement is true because "had" implies that the patient had (past tense) contracted ulcer due to H. pylori infection. I wanted to find an answer that says something like "yes, because the patient could have been infected by H. pylori and recovered". Couldn't find it so I just went with C and moved on. Stupid wording...

The reason I got this right was because of a past AAMC. I remember an old passage on H. pylori saying that not everyone who was infected necessarily got stomach ulcers because they could have fought off the infection. I remembered that, and then picked A. Kind of a dumb question.

 

[starbaduk]

This goes back to the solubility rules, all group 1 are soluble which include ammonium salt as well. Being that K+ is in group 1, it is very soluble. Take a penny and put it in a cold water, does it dissolve?????. Put a Nacl or KCL( they have the same properties because they are in the same group ) in water, it dissolves rapidly.

Actually K metal reacting violently with water is not the same thing as K+ ions dissolving in water. In fact, K+ ions do not react violently with water. They just become hydrated with water.

Potassium metal reacts with water to produce H2. I think the reaction goes something like

K + H2O -> KOH + H2

I don't really know why K reacts with water while Mg reacts very slowly. I just know it from experience. Similar group I metals like Na also react violently with water.

 

[capn jazz]

The reason I got this right was because of a past AAMC. I remember an old passage on H. pylori saying that not everyone who was infected necessarily got stomach ulcers because they could have fought off the infection. I remembered that, and then picked A. Kind of a dumb question.

I picked C because I thought that antibodies are not actively expressed unless the antigen is present because memory B cells have to be induced to develop into plasma cells to release the antibody, and the induction cause is presumably the presence of antigen...

 

[capn jazz]

Okay, PS Q41, about doing the oleic acid dealy with oil and water. I picked that it wouldn't work because water would disperse over the oil, thinking of balls of water forming on top of oil. The answer was that it wouldn't work because H2O is not cylindrical. Why is C wrong though?

 

[capn jazz]

bump! anyone?

 

[wanderer]

It says compound 1 is a stronger acid than compound 2 because the anion of compound 1 is better stabilized by:

D. Hydrogen bonding between OH and CO2-. Why can't this be due to the inductive effect, it seems like in compound 1 the orientation brings the 2 groups close together so that induction would be significant. Also hydrogen bonding should stabilize the acid just as much as the base form and should not lead to greater acidity.......

 

[capn jazz]

Induction isn't based on proximity of the atoms in space, it's based on how many atoms are between them on the molecule.

And about H-bonding - in the more acidic molecule, the protonated and deprotonated forms can be stabilized by H-bonding, sure. But in the less acidic molecule, NONE of the forms are stabilized by H-bonding, so it wants to be deprotonated even less.

 

[milindian]

Lol...idk if someone above me already posted about this (I'm too lazy to read through all the posts), but there was a glitch when I was taking this exam. It gave me the solution and explanation for item 4....and I had the option to hide solutions selected. lol....yeah, i chuckled.

 

[boaz]

It says compound 1 is a stronger acid than compound 2 because the anion of compound 1 is better stabilized by:

D. Hydrogen bonding between OH and CO2-. Why can't this be due to the inductive effect, it seems like in compound 1 the orientation brings the 2 groups close together so that induction would be significant. Also hydrogen bonding should stabilize the acid just as much as the base form and should not lead to greater acidity.......

Inductive effect depends purely on the number of bonds and the length of those bonds, not on geometry.

There is more negative charge localized on the oxygen in the base than in the acid. Therefore, the stabilization effect of H-bonding (the H partially balancing the negative charge on O) is that much stronger in the base. This is a bit on the theological side of orgo, but QM calculations probably confirm this.

 

[wanderer]

Ah, I thought that since the electronegative O of the hydroxy group was near the carboxylate group it could pull off some of the electron density towards it. So induction can only happen through intervening nuclei/covalent bonds?

I see what your saying about the H-bonding, I thought that since your actually losing an H-bond donor in the process of deprotonation, there is relatively less H-bonding on the anionic form, and therefore H-bonding would actually lead to a decrease in acidity, but what you are saying does make sense.

 

[boaz]

Ah, I thought that since the electronegative O of the hydroxy group was near the carboxylate group it could pull off some of the electron density towards it. So induction can only happen through intervening nuclei/covalent bonds?

I see what your saying about the H-bonding, I thought that since your actually losing an H-bond donor in the process of deprotonation, there is relatively less H-bonding on the anionic form, and therefore H-bonding would actually lead to a decrease in acidity, but what you are saying does make sense.

Yes, induction can only happen through bonds. BTW, in this case induction is VERY insignificant; there is hardly any inductance at all.

Even in the acid form, I don't believe there can be two simultaneous H-bonds at once. Try to work it out with a molecular model kit/software. So in effect in both the base and the acid, there is only 1 H-bond, and it has a more important effect in the base.

 

[Mae16]

Hi guys. Can somebody explain to me how D is correct for #24 on PS?:



What I don't understand is how you know that H2O2 is oxidized to O2, instead of H2O (this was what I presumed and therefore I got it wrong). To me, it seemed that H2O2 --> H2O + O-, and the highly unstable O- anions would come together to form O2. I don't know, does someone know what's going on here? Thanks!

I don't think anyone has responded to this, and I have the same question. Can anyone help? I see how it's easy to deduce what's happening to the Mg; but then I didn't know what to do. Do you look at the Cl, or the Hs or the Os? And when you look at the O, how do you know WHICH O in the product to compare it to? The O in the H20 or the O in the O2?

 

[liux0019]

The last question is about behavior biolody regarding Conditioning. And I remember there are also questions about Conditioning and Imprinting in CBT3R.
However, I never see this topic either in EK or Kaplan. I am confused will this topic still be tested in current MCAT tests? Because according the AAMC, the 10 tests are the real MCAT questions from 1992(?) to 2000. It was like 10 years ago.

 

[chencxm]

Why will someone previously had H. pylori infection and had already eliminate it have anti-H. pylori antibody circulating in their blood now? I thought antibodies are just to be put into use now and then eliminated/degraded by liver? The secondary response involves recognition by T-cells and producing new antibodies by memory B-cells. Is that right? I put D although I wasn't very satisfied with D either.

 

[SuperSaiyan3]

just took this test. Got destroyed in verbal. typical eh?

 

[SuperSaiyan3]

did anybody else find the answers to the H. Pylori experimental questions veryyyy controversial?

for example, one of the answer choices was : "Infect a healthy person with H. Pylori" to see if they would get ulcers.

Yes... that would work.. but there's no way this would be allowed in real life. This is unethical in both experimental and medical approach. You can't just INFECT a healthy person like that!!

Anybody else thought of this?

 

[brushbordermb]

did anybody else find the answers to the H. Pylori experimental questions veryyyy controversial?

for example, one of the answer choices was : "Infect a healthy person with H. Pylori" to see if they would get ulcers.

Yes... that would work.. but there's no way this would be allowed in real life. This is unethical in both experimental and medical approach. You can't just INFECT a healthy person like that!!

Anybody else thought of this?

I thought of it. However, the question did not ask for the most ethical way. I had a lot of trouble picking that answer, but I picked it because it was the answer choice that most clearly proved or disprove causation

 

[SuperSaiyan3]

I thought of it. However, the question did not ask for the most ethical way. I had a lot of trouble picking that answer, but I picked it because it was the answer choice that most clearly proved or disprove causation

yeah... I knew deep down in my heart that it would be the right answer.. but my inner conscience got the best of me... but at least now I can sleep in peace without knowing that I could be capable of intentionally making a healthy person sick... who knows.. maybe he/she would have died from the infection and what would I say to the family? How could I live with myself??

Oh the tragedy!!

 

[G1SG2]

PS Passage III, question 22:

WTF are voles!??! How am I supposed to know voles are "mouselike rodents", what in the world LOL. The passage says nothing about it, nor does that fit in anywhere in the content review that I did. Wth?

 

[wanderer]

PS Passage III, question 22:

WTF are voles!??! How am I supposed to know voles are "mouselike rodents", what in the world LOL. The passage says nothing about it, nor does that fit in anywhere in the content review that I did. Wth?

Yay for random knowledge lol. From the passage you know that the virus likely affects mammals only, so that leaves mice and humans. It isn't likely that humans got it from other humans since similar viruses were known to exist in the wild, so that leaves mice as the most likely choice.
You might think that snakes got it from eating voles, but there is nothing that would suggest that humans got it from being near snakes, mostly because they are not mammals. Hope this makes sense.

Honestly though, having a clue as to what voles are is how I got the answer.

 

[G1SG2]

Yay for random knowledge lol. From the passage you know that the virus likely affects mammals only, so that leaves mice and humans. It isn't likely that humans got it from other humans since similar viruses were known to exist in the wild, so that leaves mice as the most likely choice.
You might think that snakes got it from eating voles, but there is nothing that would suggest that humans got it from being near snakes, mostly because they are not mammals. Hope this makes sense.

Honestly though, having a clue as to what voles are is how I got the answer.

Haha. I still think it was a pretty cheap question

Here's another one:

Alanine has two pKa values: one at 2.35 and one at 9.87. At what pH would alanine exist primarily in the form of a deprotonated COOH group, giving CO2- (net negative charge)? The answer is above 9.87 Why isn't it between 6.11 and 9.87? I mean at first I thought it should've been above 6.11, which is it's pI. Isn't that the rule? That the amino acid would be primarily deprotonated at a pH above it's pI?

 

[Hemichordate]

Haha. I still think it was a pretty cheap question

Here's another one:

Alanine has two pKa values: one at 2.35 and one at 9.87. At what pH would alanine exist primarily in the form of a deprotonated COOH group, giving CO2- (net negative charge)? The answer is above 9.87 Why isn't it between 6.11 and 9.87? I mean at first I thought it should've been above 6.11, which is it's pI. Isn't that the rule? That the amino acid would be primarily deprotonated at a pH above it's pI?

If both side chains have been deprotonated, the pH of the solution would have to be greater than the pKa of both chains. If it was between 6.11 and 9.81, the chain with pKa of 2.35 would be deprotonated, but the chain with pKa of 9.87 would be protonated.

 

[Zona Pellucida]

did anybody else find the answers to the H. Pylori experimental questions veryyyy controversial?

for example, one of the answer choices was : "Infect a healthy person with H. Pylori" to see if they would get ulcers.

Yes... that would work.. but there's no way this would be allowed in real life. This is unethical in both experimental and medical approach. You can't just INFECT a healthy person like that!!

Anybody else thought of this?

Although controversial, it is basically a direct restatement of one of Koch's Postulates.

(or maybe I'm just an evil person)