Official AAMC Section Bank - Biology

[KoalaT]

So this was 100 questions for biology under the "Section Bank" material, not the "biology Volume 1/2)

What were y'alls thoughts? Has anyone taken it?

Honestly, I thought it was really hard, which kind of scares me a bit. There were a TON of questions including lab techniques and some forms of techniques I haven't become familiar with (i.e. native vs reducing SDS). There was also a ton of enzyme kinetics in relation to Kd and Hill coefficient (I never studied anything mentioning the Hill coefficient, which took me completely off-guard when I saw it come up 3-4 times with no reference in the passage). Also, it is clear an extreme understanding of metabolic pathways is needed (substrate, enzyme, product, and the structures of each one for Glyco, Krebs, and Pentose pathway)

Overall, the passages were freak'n tough, which worries me because I had heard AAMC material was easier than the TBR passages and other FL's I've been taking. In the end, I got a 72% which is extremely disappointing to me.

Has anyone else taken it? Did it seem very hard to you too?

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[aldol16]

It was definitely an increase in difficulty as compared to other practice materials but it does give you excellent practice as scientific reasoning. With regard to the specifics you mentioned, you should review cooperativity because that's an important aspect of hemoglobin function and also you should have down a solid understanding of the metabolic pathways. Not necessarily memorizing each step, but understanding each step and why it happens.

 

[KoalaT]

Ya I researched the Hill coefficient. I do understand cooperativity of course, I just had never heard of the Hill coefficient as a measurement of it. Now I know.

On the metabolism side of things, I do understand the process but there were 2-3 questions that actually would need memorization for. There was one that showed the structure of a step in Krebs, gave a blank in the middle, and showed the next structure. You had to know exactly what each structure was by memorization and deduce that it was fumarate between the two. There were a few questions like this. I think I just need to learn to write the krebs cycle and pentose pathway by hand over and over again to learn it. At the very least, it would help me get through those questions quicker.

 

[aldol16]

On the metabolism side of things, I do understand the process but there were 2-3 questions that actually would need memorization for. There was one that showed the structure of a step in Krebs, gave a blank in the middle, and showed the next structure. You had to know exactly what each structure was by memorization and deduce that it was fumarate between the two. There were a few questions like this. I think I just need to learn to write the krebs cycle and pentose pathway by hand over and over again to learn it. At the very least, it would help me get through those questions quicker.

Were the answers in terms of structures or words? Because you can figure out each step of the TCA cycle using chemical logic. For example, the structure before the blank had to be succinate and the structure after had to be malate. You know that for the purposes of the MCAT, nature can't just install a random OH group wherever (actually, P450s can but that mechanism is beyond the scope of the MCAT). It has to oxidize the aliphatic carbon first before it can hydroxylate. An easy way to do that would be hydroxylation of an alkene. If the answers are given in terms of structures, it should be pretty easy to rule out whichever ones could not possibly be an intermediate.

I encountered something similar in the AAMC exam, which required knowledge of how hydrolysis of natural bonds works, in general. It was a disaccharide with a nitrile and benzyl group. The question asked you which structure would give, upon hydrolysis, HCN, benzaldehyde, and the monosaccharides.

 

[Thoroughbred_Med]

So this was 100 questions for biology under the "Section Bank" material, not the "biology Volume 1/2)

What were y'alls thoughts? Has anyone taken it?

Honestly, I thought it was really hard, which kind of scares me a bit. There were a TON of questions including lab techniques and some forms of techniques I haven't become familiar with (i.e. native vs reducing SDS). There was also a ton of enzyme kinetics in relation to Kd and Hill coefficient (I never studied anything mentioning the Hill coefficient, which took me completely off-guard when I saw it come up 3-4 times with no reference in the passage). Also, it is clear an extreme understanding of metabolic pathways is needed (substrate, enzyme, product, and the structures of each one for Glyco, Krebs, and Pentose pathway)

Overall, the passages were freak'n tough, which worries me because I had heard AAMC material was easier than the TBR passages and other FL's I've been taking. In the end, I got a 72% which is extremely disappointing to me.

Has anyone else taken it? Did it seem very hard to you too?

72% is a fantastic score. Section banks are noticeably tougher than other material.

No surpise, they are the best review materials out there. Definitely understand all of the lab techniques you mentioned. More importantly, understand how to reason within the data presented in the passages. I got a 59% on bio section bank -____-

 

[KoalaT]

Were the answers in terms of structures or words? Because you can figure out each step of the TCA cycle using chemical logic. For example, the structure before the blank had to be succinate and the structure after had to be malate. You know that for the purposes of the MCAT, nature can't just install a random OH group wherever (actually, P450s can but that mechanism is beyond the scope of the MCAT). It has to oxidize the aliphatic carbon first before it can hydroxylate. An easy way to do that would be hydroxylation of an alkene. If the answers are given in terms of structures, it should be pretty easy to rule out whichever ones could not possibly be an intermediate.

I encountered something similar in the AAMC exam, which required knowledge of how hydrolysis of natural bonds works, in general. It was a disaccharide with a nitrile and benzyl group. The question asked you which structure would give, upon hydrolysis, HCN, benzaldehyde, and the monosaccharides.

It was structures. It was a 4C double carboxylic acid ---> X ---> double 4C carboxylic acid with an -OH. That's all

I guess you could still use the order and the fact that it is 4c to realize it has to be in the 3 steps after 2 CO2 are gone.

 

[KoalaT]

72% is a fantastic score. Section banks are noticeably tougher than other material.

No surpise, they are the best review materials out there. Definitely understand all of the lab techniques you mentioned. More importantly, understand how to reason within the data presented in the passages. I got a 59% on bio section bank -____-

I actually did quite well on them. Like I didn't know the difference between reductive, native, and denaturing SDS, but using common sense, I actually got all those right.

 

[kitkat13]

I actually did quite well on them.

I am super struggling on them :'(

I guess what do you think you focused on that is helping you do well?

 

[KoalaT]

I am super struggling on them :'(

I guess what do you think you focused on that is helping you do well?

I meant I did well on the lab technique questions despite my poor understanding of the differences between reducing, native, and denaturing. Overall, I agree, the section bank was a SERIOUS struggle. The whole time I was just thinking, wholly crap. Surprisingly as I review, I did better than I thought.

I didn't really focus on anything specific. I just did every TBR chapter, passage, EK1001 supplemented to it, and TPRH science workbook. I also have been studying for 120 days straight now (with 33 more to go!), so that helps 😛

 

[aldol16]

I guess what do you think you focused on that is helping you do well?

Section Bank material is not difficult in terms of concepts. You should know all the concepts. What's difficult for most students is the scientific reasoning aspect of the questions. Surprisingly, many schools don't actually emphasize reasoning and instead emphasize memorization of raw material. That may have gotten you through your university science classes, but it won't cut it on the new MCAT. As you can tell from the Section Bank questions, it's about using logic and reasoning based on your pre-existing knowledge to reason out the answer to a particular problem.

 

[KoalaT]

Section Bank material is not difficult in terms of concepts. You should know all the concepts. What's difficult for most students is the scientific reasoning aspect of the questions. Surprisingly, many schools don't actually emphasize reasoning and instead emphasize memorization of raw material. That may have gotten you through your university science classes, but it won't cut it on the new MCAT. As you can tell from the Section Bank questions, it's about using logic and reasoning based on your pre-existing knowledge to reason out the answer to a particular problem.

I highly agree. The section bank was very passage and analysis based. Although it did throw in some knowledge based stuff, which I think is to tell you "hey, we expect you to know this". Ex: The metabolic questions, questions about lab techniques, Hill coefficient, etc. Or the one I found shocking: the average amino acid weighs 110 Da. Ya, they expected you to blatantly know that by asking the weight of a 228 AA tetramer. Straight up, you had to know the average weight was 110.

 

[wheatthinners]

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[Wolfpack93]

I highly agree. The section bank was very passage and analysis based. Although it did throw in some knowledge based stuff, which I think is to tell you "hey, we expect you to know this". Ex: The metabolic questions, questions about lab techniques, Hill coefficient, etc. Or the one I found shocking: the average amino acid weighs 110 Da. Ya, they expected you to blatantly know that by asking the weight of a 228 AA tetramer. Straight up, you had to know the average weight was 110.

Curve generators. Questions like these are to be expected and why people don't get 100% correct. But still it is pretty ridiculous to be expected to memorize such trivial info like that.

 

[KoalaT]

Did you do the Section Bank under timed conditions?

The section bank did not have an option to do timed conditions. I timed myself (passage by passage, not 1 long timing) and did stick to it on about 50% of passages. The other 50% I found myself with 2 questions left when time ran out and cheated a little. The questions required a lot of passage analysis and were pretty dense.

It is possible they didn't put on timed conditions and made the passages more dense simply to get you to learn the proper way to analyze passages for the MCAT. Cause I don't have timing trouble on any other practice material and practice with reduced timing.

 

[sookykim1]

Can someone help me understand Q17 that asks which pair of WT and mutant alleles contain a mutation? I have a hard time seeing it. I know it has to do with palindromic sequence but I feel like the other choices also disrupt a palindromic sequence. Thank you in advance!

 

[theonlytycrane]

@KoalaT did you get through the entire TPRH science workbook? Or did you focus on specific sections of this?

 

[KoalaT]

Can someone help me understand Q17 that asks which pair of WT and mutant alleles contain a mutation? I have a hard time seeing it. I know it has to do with palindromic sequence but I feel like the other choices also disrupt a palindromic sequence. Thank you in advance!

This question requires you understand that southern blotting deals with digestive enzymes and DNA. You break up a DNA strand using digestive enzymes and then use electrophoresis to compare size of sequences and maybe even the order etc etc.

The answer is the one that has a mutation in a palindromic sequence (a 4-6 NT sequence that create a mirror image in the other strand). The correct answer is the one with the mutation within the palindromic sequence. All the other answers still have the palindromic sequence intact and would therefore be cut by digestive enzymes the same and the difference would be unnoticeable in southern blotting. In this case, the palindrome was AACGTT, which has a complement of TTGCAA, which was interrupted only in the correct answer.

The palindromic sequences don't actually have to be the same forward and backwards as much as they have to be the same on the opposite strand

This was a very difficult question, which I got incorrect as well.

 

[KoalaT]

@KoalaT did you get through the entire TPRH science workbook? Or did you focus on specific sections of this?

I am almost through the entire thing. I cut it into sections that simulated a full test. I would create a full length (10 passage) Chem/phys section and a full length Bio section. This meant I would take 5 Gchem passages (1 section from a random assortment of topics. i.e. 1 from gases, 1 from fluids, 1 from atomic theory, etc). Then I took 4 random physics passages in the same manner. Then I put in 1 Ochem passage that had to do with some sort of chemistry (Sn1/sn2, connectivity, bonding, etc).

For the bio section, I took 9 random biology passages from different topics and then 1 OChem passage from the "Biologically relevant chemicals" section.

I did this everyday by completing the Gchem/phys section I created and grading it. Then I did a small verbal practice (either TPR or an LSAT). Graded it. Then I did the biology section I created and graded it. The next day, I would create new tests in the manner described (trying to vary the topics randomly and get a little bit of everything) and do it all over again. I would say I've done about 70-80% of the total passages already.

 

[sookykim1]

This question requires you understand that southern blotting deals with digestive enzymes and DNA. You break up a DNA strand using digestive enzymes and then use electrophoresis to compare size of sequences and maybe even the order etc etc.

The answer is the one that has a mutation in a palindromic sequence (a 4-6 NT sequence that create a mirror image in the other strand). The correct answer is the one with the mutation within the palindromic sequence. All the other answers still have the palindromic sequence intact and would therefore be cut by digestive enzymes the same and the difference would be unnoticeable in southern blotting. In this case, the palindrome was AACGTT, which has a complement of TTGCAA, which was interrupted only in the correct answer.

The palindromic sequences don't actually have to be the same forward and backwards as much as they have to be the same one e

This was a very difficult question, which I got incorrect as well.

Thank you, I'll take another closer look at it 🙂

 

[averroesiaw]

Hi all,
Any chance you guys are also finding mistakes in the AAMC question and section banks?
For example, Section Bank Bio Passage 3 question 22 is regarding molecular weight of an inactive tetramer. Apparently we are just supposed to know that the average MW for an AA is 110dk, okay... somewhat fair... BUT the solution reports ¨... as indicated by figure 1...¨ the issue is... THERE IS NO FIGURE IN THE PASSAGE. I asked others to view the same passage in Safari, chrome and IE and noone had figures shows in the passage. whats up with that?
this isnt the first time im finding typos and mistakes in aamc solutions and passages....