USABO 2016-2017

I think alot of the schools glitched and they don’t know which ones. Nobody at my school had their scores until I contacted CEE. https://www.usabo-trc.org/contact-us

29.38
Semifinalist
for four consecutive years

Anybody have any experience with being ridiculously close to the cutoff? Does CCE ever bump up scores to semifinalist if some of the top 10% do not sign up for semi testing? I scored a 23.98, which is mildly infuriating…

(Just a note, this is the first time my school has ever run the test so I’m kinda clueless about a few the technicalities of the process - sorry if this is a stupid question)

@insertcleverpun Yeah they don’t bump you up. Even if if you are 0.03 points away from the cutoff (which has happened before), they don’t bump you which really sucks.

anyone else still without scores?

so, I somehow got a 19.57 even thought I felt really confident about the entire thing, I emailed Ms. Frame to see if they put my score in wrong somehow, I was so confident i made it…

I think I’m just pathetic at biology and still in shock

@PercyFowl
Relax man, you’re great at biology, you scored above average on a test designed for the best biology students in the nation, and you probably have another year to take the exam.

They don’t bump you. What really sucks is that if those people had not cheated, you would have probably made it.

For the people who took the semifinals last year, how does it compare with the recent ones (2011-2013)? Is it significantly harder? Also what was the cutoff percentage last year? Thanks guys xD

Also can someone explain me the break down of the test? (Total points, Number of points/questions per section, Pace)

@egghead8 Did you get it yet?

@thunderlight8 yup, got it. unfortunately 0.2 off from semifinalist

Was a collab doc ever made to study off?

@egghead8 Ouch, well if you study just a bit more you will make it next year=)

Is there anyone who would want to create a google docs to review this years exam once again
I want to improve for next year’s exam

Just a few questions about the 2011 USABO Semifinal Exam, if anyone would be interested in answering them…
BTW here’s the link for the exam: https://goo . gl/KbBFqw (take out the spaces, for some reason it thinks its explicit :/)

  1. (Problem 4) Why could you not add a bacterial promoter as well, due to the fact the you are using a bacterium (specifically E. coli) to amplify a human gene using PCR?
  2. (Problem 13) Monocots have paralleled veined leaves, not dicots, thus making the question incorrect?
  3. (Problem 40) Could someone please explain how to solve this problem? I keep on getting a different answer :(
  4. (Problem 51) Again, could someone provide a solution?
  5. (Problem 57) I suck at genetics :( ... My solution :

Probability that both of children are boys: (1/2)^2
Probability that both children are O type: (1/4)^2 since both parents I^A I^O
Probability that both children are Rh-: (1/2)^2

→ Total Probability is 1/256??? but doesn’t match with answer

  1. (Problem 83) Since Grave's Disease is hyperthyroidism --> increased T3 and T4 and decreased TSH by negative feedback, B is the (closest to) right answer?
  2. (Problem 95) Beta receptors activated by catecholamines lead to hypertension, dizziness, vasoconstriction --> C?
  3. (Problem 106) How is choice B not true, as selective pressures by the environment lead to better fit organisms --> evolution?

Thanks (in advance)!

@phat97

4: E. coli DNA polymerase would be unable to function in the heating/cooling cycles of standard PCR conditions (need heat resistant DNA polymerase like Taq)

13: Central primary xylem and active vascular cambium (secondary growth) is indicative of dicots, so that should be the answer. I'm not sure about the parallel veins (might be a mistake/exception?)

40: The genes linked and 12 map units apart. This means that 12% of the offspring are recombinants. In this case, the recombinants are the genotypes AB and ab. A heterozygous individual would produce gametes in which 12% are recombinants, so the expected frequencies would be 6% AB 44% Ab 44% aB 6% ab

51: Not sure about this one either.

57: I agree with your answer. The answer key might be wrong but I'm not sure.

83: I'm not entirely sure, but here's my theory: a common treatment for Graves disease is radioactive iodine therapy. The thyroid gland is still being hyperactive, but it incorporates the radioactive iodine into its hormones, destroying them. When the patient forgets to take the radioactive iodine, there is less iodine in the body and as a result less hormone is produced and goiter forms (commonly results from iodine deficiency).

95: Beta-adrenergic receptors are the targets of epinephrine. Epinephrine usually induces the fight-or-flight response involving vasodilation in peripheral muscles and the heart (why it helps with COPD), increases respiration (why it helps with asthma), and inhibition of digestion and the reproductive system through vasoconstriction. The answer should be A (decreased sensitivity to inflammation, inhibition of uterine contraction, hypotension)

106: The individuals themselves don't evolve, the population as a whole does, so D is the correct answer.

Hope this helps!

@Solanaceae Thank you very much!

for those who took it today how was it? My semifinal exam is tomorrow and I dont feel ready tbh