The Official August 16, 2013 MCAT Thread

[gettheleadout]

Welcome everyone! For those following the SN2ed or a similar 3-month study schedule, prep should begin in the next few weeks.

Hope to see some ambitious and optimistic people here with me, and shout out to the 3/23'ers from before I bailed on that test date.

Let's go!

---

Members don't see this ad.

 

[CUAnes12]

Point and Shoot.

This...may be the best memory device I've ever seen.

 

[inycepoo]

May I ask why you guys know this?

Compliments of a current M1 from the Step 1 "bible." http://www.amazon.com/First-Aid-USMLE-Step-2013/dp/0071802320

 

[inycepoo]

Just switched test date from 8/9 to 8/16 so I guess I'm joining this thread!

Traitor.

 

[Ansar]

208. Although human behavior ensures the success of each
new generation of corn, selective breeding by humans has
genetically altered corn so that it could not survive in the
wild without human intervention. Corn population is
controlled, and most of the corn seeds are eaten or
become spoiled. The relationship between humans and
corn is best described as:
A. commensalism because humans benefit and com is
neither benefited nor harmed.
B. commensalism because there is no true benefit to either
species.
C. parasitism because humans benefit and corn is
harmed.
D. mutualism because both species benefit.

So...I guess corn is not harmed by being forced to depend on humans now? Sorry...is it really so obvious that corn benefits from humans (i.e. the answer is D)?

 

[HotHamH2O]

208. Although human behavior ensures the success of each
new generation of corn, selective breeding by humans has
genetically altered corn so that it could not survive in the
wild without human intervention. Corn population is
controlled, and most of the corn seeds are eaten or
become spoiled. The relationship between humans and
corn is best described as:
A. commensalism because humans benefit and com is
neither benefited nor harmed.
B. commensalism because there is no true benefit to either
species.
C. parasitism because humans benefit and corn is
harmed.
D. mutualism because both species benefit.

So...I guess corn is not harmed by being forced to depend on humans now? Sorry...is it really so obvious that corn benefits from humans (i.e. the answer is D)?

I think I would answer A...but that's probably wrong. I just know that selective breeding is beneficial to humans otherwise why would they do it.

 

[Platonic]

208. Although human behavior ensures the success of each
new generation of corn, selective breeding by humans has
genetically altered corn so that it could not survive in the
wild without human intervention. Corn population is
controlled, and most of the corn seeds are eaten or
become spoiled. The relationship between humans and
corn is best described as:
A. commensalism because humans benefit and com is
neither benefited nor harmed.
B. commensalism because there is no true benefit to either
species.
C. parasitism because humans benefit and corn is
harmed.
D. mutualism because both species benefit.

So...I guess corn is not harmed by being forced to depend on humans now? Sorry...is it really so obvious that corn benefits from humans (i.e. the answer is D)?

I think I'd probably put D. Although you might make the argument that changing corn harmed corn, I think you have to make a distinction between the natural corn and the modified corn, since they're genetically distinct. And the modified corn definitely has a mutual relationship with humans since we eat it and it couldn't survive without us.

 

[Ansar]

I think I'd probably put D. Although you might make the argument that changing corn harmed corn, I think you have to make a distinction between the natural corn and the modified corn, since they're genetically distinct. And the modified corn definitely has a mutual relationship with humans since we eat it and it couldn't survive without us.

I see! I think my problem in reasoning was that I read it as like us humans just making the corn dependent on us but thinking that, well, we're not really dependent on corn either...we can live without it (so I thought it was like we were parasitic since we changed the corn [for the worse, if you think about how we made it dependent on us] so we could benefit from it...). The posted answer is D.

Thanks Platonic!

 

[IcemanMD]

Thanks for the penis mnemonics everyone! Are you all making flash cards too? I have been trying to use anki but I haven't reviewed them extensively yet..

 

[Sarvish]

Thanks for the penis mnemonics everyone! Are you all making flash cards too? I have been trying to use anki but I haven't reviewed them extensively yet..

I just have note sheets that I review on my commute. They don't have too much on them and I'm trying to keep them down to a page per subject. Physics has a few formulae that don't stick in my head, gen chem has some of the mnemonics and little tidbits of info, orgo chem has some of the IR/NMR shifts and reactions, and bio has things that I can never remember for some reason like the location of processes in the cell.

It just helps psychologically for me, learning 4 pages of information seems a lot less intimidating.

 

[inycepoo]

This...may be the best memory device I've ever seen.

 

[IcemanMD]

I just have note sheets that I review on my commute. They don't have too much on them and I'm trying to keep them down to a page per subject. Physics has a few formulae that don't stick in my head, gen chem has some of the mnemonics and little tidbits of info, orgo chem has some of the IR/NMR shifts and reactions, and bio has things that I can never remember for some reason like the location of processes in the cell.

It just helps psychologically for me, learning 4 pages of information seems a lot less intimidating.

This is a great idea actually. Thanks for the suggestion

 

[Sarvish]

This is a great idea actually. Thanks for the suggestion

I've done it for most of my biology courses in university so far. No matter how lazy you are, one page of information doesn't look like much to remember regardless of how small the writing is. Really, staring at it for a while commits some of it to your photographic memory and when you furiously underline other parts that you keep forgetting, they eventually stick too.

 

[balla121]

found a mistake in chemistry ch 3 equilibrium passage today in case anyone hasn't done that one yet or missed the error. It is in passage 12 question 81.

81. which will shift reaction 4 to the left,

reaction 4:
2 NO2 (g) + H2O (l) <--> HNO2 (aq) + HNO3(aq)

answer they gave was D. removal of water from solution; It is incorrect because pure solids and liquids do not effect equilibriums.

excerpt from page 178 TBR chem book 1:

"It is important to note that changing an equilibrium system by adding a pure solid or a pure liquid does not disrupt the equilibrium nor change the equilibrium constant"

 

[IcemanMD]

found a mistake in chemistry ch 3 equilibrium passage today in case anyone hasn't done that one yet or missed the error. It is in passage 12 question 81.

81. which will shift reaction 4 to the left,

reaction 4:
2 NO2 (g) + H2O (l) <--> HNO2 (aq) + HNO3(aq)

answer they gave was D. removal of water from solution; It is incorrect because pure solids and liquids do not effect equilibriums.

excerpt from page 178 TBR chem book 1:

"It is important to note that changing an equilibrium system by adding a pure solid or a pure liquid does not disrupt the equilibrium nor change the equilibrium constant"

Maybe I'm reading too much into this but won't the removal of water cause there to be less HNO2 and HNO3 because they depend on the water to be in solution?

 

[Barker Posey]

found a mistake in chemistry ch 3 equilibrium passage today in case anyone hasn't done that one yet or missed the error. It is in passage 12 question 81.

81. which will shift reaction 4 to the left,

reaction 4:
2 NO2 (g) + H2O (l) <--> HNO2 (aq) + HNO3(aq)

answer they gave was D. removal of water from solution; It is incorrect because pure solids and liquids do not effect equilibriums.

excerpt from page 178 TBR chem book 1:

"It is important to note that changing an equilibrium system by adding a pure solid or a pure liquid does not disrupt the equilibrium nor change the equilibrium constant"

In this case water is a reactant, so is included. The book is right.

 

[inycepoo]

In this case water is a reactant, so is included. The book is right.

When would a solid or liquid compound not be a reactant? If it weren't, it wouldn't be written in the reaction. Do you mean to say that if a solid/liquid is written in the equation, then its removal/addition would affect equilibrium? Surely, that's not how it works..

 

[Barker Posey]

When would a solid or liquid compound not be a reactant? If it weren't, it wouldn't be written in the reaction. Do you mean to say that if a solid/liquid is written in the equation, then its removal/addition would affect equilibrium? Surely, that's not how it works..

You see how the hydrogens from the water are split on the products side? The water is reacting. If it's inert, it's not affecting equilibrium. In this case, making aqueous reactants, you're affecting the molarity of the products by removing water, which does change Keq. We normally ignore solvents because they're considered very dilute and therefore negligible. Not so in this case.

 

[balla121]

You see how the hydrogens from the water are split on the products side? The water is reacting. If it's inert, it's not affecting equilibrium. In this case, making aqueous reactants, you're affecting the molarity of the products by removing water, which does change Keq. We normally ignore solvents because they're considered very dilute and therefore negligible. Not so in this case.

I think you're half right about this...
I'm seeing that the book is right about the shift to the left due to the INcrease in concentration (moles/Lsolution) of the products when you take out water

BUT

Water will not effect the equilibrium as a reactant. There is no way that water will fit into the Keq equation. If it doesn't fit in the keq equation, then it doesn't affect the equilibrium as a reactant.

http://forums.studentdoctor.net/archive/index.php/t-826140.html

 

[Platonic]

 

[Ansar]

Wow, BS content review for the systems is killing me. So many details. Maybe that's why I didn't do well in bio classes.

 

[Platonic]

The electricity/Circuits section in TPR is far, far better than TBR.

 

[Barker Posey]

I think you're half right about this...
I'm seeing that the book is right about the shift to the left due to the INcrease in concentration (moles/Lsolution) of the products when you take out water

BUT

Water will not effect the equilibrium as a reactant. There is no way that water will fit into the Keq equation. If it doesn't fit in the keq equation, then it doesn't affect the equilibrium as a reactant.

http://forums.studentdoctor.net/archive/index.php/t-826140.html

Water isn't specifically in the Keq except that it's what molarity is based on (moles/L). Water is water. It's an incompressible liquid so its concentration will always be the same. When the concentration of products changes with the removal of a reactant (water) but the concentration of reactants does not change, then the Keq changes. When the water is not reacting, adding it affects both sides of the reaction equally and Keq does not change. It's probably a more complicated concept than will be on the MCAT.

 

[HotHamH2O]

The electricity/Circuits section in TPR is far, far better than TBR.

true statement

 

[Platonic]

Which part of OChem was recently taken off the MCAT? I recall reading on SDN that alkynes are not on it, as well as aromatic stuff.

 

[inycepoo]

Which part of OChem was recently taken off the MCAT? I recall reading on SDN that alkynes are not on it, as well as aromatic stuff.

Go get the content outline and check it out.

 

[Platonic]

I'm confused about the number of chromosomes in the human genome. It's supposedly 23. But there are 22 non sex chromosomes, and two sex chromosomes, so 24 types in all...? Women should have 23 types of chromosome, men 24, right?

 

[inycepoo]

I'm confused about the number of chromosomes in the human genome. It's supposedly 23. But there are 22 non sex chromosomes, and two sex chromosomes, so 24 types in all...? Women should have 23 types of chromosome, men 24, right?

X and Y chromosomes are both sex chromosomes, and therefore count as 1 "type," if such nomenclature is ever even to be used. Women have 23 pairs, and so do men. Frivolous.

 

[Platonic]

X and Y chromosomes are both sex chromosomes, and therefore count as 1 "type," if such nomenclature is ever even to be used. Women have 23 pairs, and so do men. Frivolous.

So there are 22 non-sex chromosomes and "1" sex chromosome, and two different types of this one chromosome....but the other 22 have only one type. Is this correct? And by one type, I mean when you have a a non-sex pair of chromosomes, they are homologous.

 

[inycepoo]

So there are 22 non-sex chromosomes and "1" sex chromosome, and two different types of this one chromosome....but the other 22 have only one type. Is this correct? And by one type, I mean when you have a a non-sex pair of chromosomes, they are homologous.

There are 2 sex chromosomes, X and Y. This is why I said your use of "type" is misleading. It is not "there is 1 sex chromosome" but "2 types of them." They are known as the 2 sex chromosomes. Males have X/Y; females have 2 Xs. We all have "1 pair" of sex chromosomes. Whether they're X or Y does not affect what we call them.

You are overcomplicating things and digging into circumlocution. You understand it. Move on to higher yield topics, dude...

 

[Platonic]

There are 2 sex chromosomes, X and Y. This is why I said your use of "type" is misleading. It is not "there is 1 sex chromosome" but "2 types of them." They are known as the 2 sex chromosomes. Males have X/Y; females have 2 Xs. We all have "1 pair" of sex chromosomes. Whether they're X or Y does not affect what we call them.

You are overcomplicating things and digging into circumlocution. You understand it. Move on to higher yield topics, dude...

My intent is not to sound nit picky.I just want to understand completely before moving on, since this is a foundational topic. I just checked out "human genome" on wikipedia, and they list chromosomes 1-22, X, and then Y. That's 24 human chromosomes. The page never said there are 23 human chromosomes, simply that every cell has 23 pairs of chromosomes.

 

[Platonic]

I have another biology question, sorry ahead of time if it comes off as nit picky and annoying. This question concerns when the cell is considered haploid during meiosis. TPR bio book just said it's considered haploid after telephase 1. However, for a particular replicated chromosome after telephase 1, it appears that the sister chromatids are actually not identical due to recombination. Therefore, they are actually non identical copies of the same chromosome, aka they're homologous chromosomes. So they should represent two different copies, making the cell technically diploid but "almost" haploid since there will be little genetic difference beteen the copies. Anyway, if this were to pop up on the MCAT, it's pretty much agreed that the correct answer is haploid after telephase 1, right?

 

[inycepoo]

Yes. Haploid because n=23.

 

[Platonic]

right. But n=23 only if the sister chromatids are considered to hold identical information. They really hold slightly different information though. But apparently not enough to be counted separately.

 

[amethystdoc]

right. But n=23 only if the sister chromatids are considered to hold identical information. They really hold slightly different information though. But apparently not enough to be counted separately.

This always used to confuse me, just remember this.
Meiosis starts off with 2n-double stranded
After meiosis 1, the 2 daughter cells are 1n-double stranded
After meiosis 2, the 4 daughter cells are 1n-single stranded

 

[CUAnes12]

Anyone else here actually taking a course? I tried doing the self-study but realized that it just wasn't beneficial since I took the pre-reqs so long ago.

So if anyone is taking Kaplan, can we be class buddies?

 

[inycepoo]

right. But n=23 only if the sister chromatids are considered to hold identical information. They really hold slightly different information though. But apparently not enough to be counted separately.

That's the whole point! Genetic diversity woohoo! Good thing geneticists didn't make it more complicated this time around. Different looking babies!

 

[IL Pre Med]

Anyone else here actually taking a course? I tried doing the self-study but realized that it just wasn't beneficial since I took the pre-reqs so long ago.

So if anyone is taking Kaplan, can we be class buddies?

I'm taking a Princeton course. I'm like you and needed some structure and schedule. Also, I really like the online material they give you, which I know Kaplan has as well.

 

[inycepoo]

Who else despises giving prep companies more money and is self-studying?

 

[fudGez14]

hey guys, another 8/16er here! i just took aamc#3 as my first FL practice CBT test (just finished two weeks of a prep course), and got a 9PS, 10V, 9BS for a total of 28. in your opinion/experience, do people generally improve a lot (im hoping for 35+) after their first FL exam? or is the improvement im looking for a bit too ambitious?

 

[inycepoo]

hey guys, another 8/16er here! i just took aamc#3 as my first FL practice CBT test (just finished two weeks of a prep course), and got a 9PS, 10V, 9BS for a total of 28. in your opinion/experience, do people generally improve a lot (im hoping for 35+) after their first FL exam? or is the improvement im looking for a bit too ambitious?

Yes, people generally improve, though to varying degrees depending on the person, study habits, and other factors. No one can really estimate how much you'll go up. Time will tell, but anything is possible with the right strategy.

Do keep in mind that AAMC #3 is "significantly easier," as TPR puts it, than the MCAT nowadays since it was released a while ago and is thus an older exam.

Coincidentally, I took #3 today too! 12PS/13VR/13BS. Aiming for a 36+ as well. Good luck!

 

[Platonic]

Yes, people generally improve, though to varying degrees depending on the person, study habits, and other factors. No one can really estimate how much you'll go up. Time will tell, but anything is possible with the right strategy.

Do keep in mind that AAMC #3 is "significantly easier," as TPR puts it, than the MCAT nowadays since it was released a while ago and is thus an older exam.

Coincidentally, I took #3 today too! 12PS/13VR/13BS. Aiming for a 36+ as well. Good luck!

You're done with content review already? I'm done with physics/gen chem, and half of biology. I'm skipping formal content review in the other half, since I just took bio 2, which covered the material. I will skip orgo 2 content as well, and spend maybe a day or two brushing up on orgo 1 content. Then I'll take the self assessment package and use that to judge whether or not I need more content review. If not, I'll work on finishing as many passages as possible from TBR/EK/TPRH SW/Kaplan Section tests. Then move on to FL's one month out.

BTW, awesome score on AAMC 3. People say its easier, but from the FL reports I've seen, the scores on this one are right in line with the other FL scores.

 

[Sarvish]

You're done with content review already? I'm done with physics/gen chem, and half of biology. I'm skipping formal content review in the other half, since I just took bio 2, which covered the material. I will skip orgo 2 content as well, and spend maybe a day or two brushing up on orgo 1 content. Then I'll take the self assessment package and use that to judge whether or not I need more content review. If not, I'll work on finishing as many passages as possible from TBR/EK/TPRH SW/Kaplan Section tests. Then move on to FL's one month out.

BTW, awesome score on AAMC 3. People say its easier, but from the FL reports I've seen, the scores on this one are right in line with the other FL scores.

You're further than me. I think I'm half done all my content, was hoping to have content completely done by the 16th and then go through 12 practice tests ever (8 AAMC, 4 Kaplan)

 

[Platonic]

You're further than me. I think I'm half done all my content, was hoping to have content completely done by the 16th and then go through 12 practice tests ever (8 AAMC, 4 Kaplan)

You're taking it 8/16 too? Good to know I'm not behind then.

 

[inycepoo]

You're done with content review already? I'm done with physics/gen chem, and half of biology. I'm skipping formal content review in the other half, since I just took bio 2, which covered the material. I will skip orgo 2 content as well, and spend maybe a day or two brushing up on orgo 1 content. Then I'll take the self assessment package and use that to judge whether or not I need more content review. If not, I'll work on finishing as many passages as possible from TBR/EK/TPRH SW/Kaplan Section tests. Then move on to FL's one month out.

BTW, awesome score on AAMC 3. People say its easier, but from the FL reports I've seen, the scores on this one are right in line with the other FL scores.

What do people normally mean when they say content review? Just reading? If so, then content review is so boring I can't even. I can't just sit there and read things I know already and tell myself it's productive. So yeah, I just did the whole TBR set of passages and only reading the parts related to what I got wrong. That was like 2 weeks and change with a lot of messing around and not being serious in studying lol. Now I've got 26 FLs to go through so I started this past Monday and being serious.

Thanks! It was a big improvement over my TPR FLs thus far so that's a good sign; always love me some hard mock ups. AAMC 3 is definitely easier lol. If the actual test is like that, then...hooray. But sadly, no :\

P.S. I'm actually an 8/9er, but that thread is dead and boring.

 

[Ansar]

What do people normally mean when they say content review? Just reading?

I think it's everything that isn't exclusively full-length practice exams?

Halfway done with Biology, and getting Physics done faster than expected

 

[Sarvish]

Obligatory complaint about how dense bio chapters are. They just don't flow as well as the other subjects. I mean there's still lots to understand and piece together but the majority of it is flat out memorizing.

 

[inycepoo]

Obligatory complaint about how dense bio chapters are. They just don't flow as well as the other subjects. I mean there's still lots to understand and piece together but the majority of it is flat out memorizing.

You mean TBR? Or in general? Majority of bio is flat out memorization lol

 

[Sarvish]

You mean TBR? Or in general? Majority of bio is flat out memorization lol

Even EK, it takes twice as long as anything else, even orgo which I suck at.

I try to avoid saying bio is flat out memorization because I always get yelled at by all the life science kids.

 

[inycepoo]

Even EK, it takes twice as long as anything else, even orgo which I suck at.

I try to avoid saying bio is flat out memorization because I always get yelled at by all the life science kids.

I said majority. Not all, since there's still a good amount of critical thinking involved what with the methodology of experiments, interpretation of results, and etc. But mostly memorization.

If it's taking forever, it probably means you have faulty knowledge. Womp.

 

[Ansar]

Jumping on the "Bio review sucks~!" bandwagon...
Chemistry and Physics have gone by swimmingly, but this is just straight up "Shove it in your brain and shut up."