@ivyrunnernyc the cutoff ranges from 21-29. Last year’s cutoff was 22.5 I think because it was relatively more difficult than the previous ones.
Test is coming up in a week. What are you guys doing for last minute studying? lol my darn finals are right now so I’m studying for both biology olympiad and my finals which is a serious pain in the butt.
Ayy lmao studying…. I maybe haven’t been doing that.
So I was going through past open exams (namely the 2012 one) and there’s a question about reagent tests called biuret, sudan, and benedict’s. Besides that, there were a bunch of questions dealing with terms I have never heard before… Is this stuff in Campbell’s because I don’t remember seeing it, and if it isn’t, am I supposed to be using another textbook to learn these things? Thanks!
The reagent tests are not in Campbell. You should probably know which ones test for what. For example, Sudan tests for presence of lipids. Benedict tests for simple sugar like glucose. Biuret tests for peptide bonds, so basically proteins. And Campbell covers majority of the questions. (I took the test yesterday and got a 38). And there is a bit of psychology in it (the habituation question). But for the random questions like which species (btw this was in Campbell) has reduced pectorial muscles, you need luck on your side. But for the most part, just rely on reasoning and pure logic and it will allow you to bs through questions you didnt learn about.
Do you guys know where to find cutoff scores for years way back like 2004? I can’t seem to find a place that lists the cutoffs even though it’s not like classified info or anything.
@Demonslayer1234 Thank you!! Ugh time to go through notes I guess xD
Congrats btw- a 38 is really good
@polkadotsock Thanks! But really, it comes down to the actual test. I’m praying (and studying hard of course 
). Just wondering, how far do you guys want to go?
@Demonslayer1234 As far as I can go haha–hopefully at least semifinals if not finals.
Is anyone using the links in the USABO Student Resource Center to study? Are they worth looking at?
making semis is fine by me, but honestly, not sure if I can make it that far bc I have no time to read all of campbells before the test so I’m just skimming campbells and notes alternatively…
how would you know which amino acids contribute most significantly or least significantly to the tertiary structure of a protein?
whichever ones have the most potential to hydrogen bond, or engage in van der waals interactions and stuff like that bc thats what defines tertiary structure? not sure lol
@alphatr0n @polkadotsock My teacher said it would be glycine, as it is the most simple.
@ccuser00 @polkadotsock @alphatr0n the most important amino acids depend on the type of protein. For most proteins, cysteine is pretty important because it forms disulfide bridges which stabilize the tertiary structure. However, USABO probably won’t ask “which is the most important amino acid.” It would ask what the effect is when certain amino acids are changed to other ones. For example, if hydrophilic amino acids on the exterior of the protein were changed to hydrophobic ones they would try to aggregate in the interior to avoid the aqeous environment. This would greatly change the tertiary structure of the protein, inhibiting its functional ability. Or, if a negatively charged amino acid was changed to a positively charged amino acid, it could change the ionization patterns of the protein in certain pH levels. This, is also significant. (Btw, glycine is important because since it has only a hydrogen for its R group it can fit in tight corners in the interior of the protein. That is why its important since it can fit in places where other amino acids can’t.)
How long does the semifinal exam take?
Reading these comments makes me scared about the actual test.
@DicksNotAllowed 3 hours
@Demonslayer1234 Thanks brah.
@awesomepolyglot don’t be scared!! if you study through the campbell book, you’ll have a pretty big chance of making it into semis!