October 2009 SAT II - Biology

Test Preparation SAT Subject Test Preparation
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<p>hahah too bad my bio class (supposedly one level higher than AP) went into such great depth over molecular bio. i had so much difficulty remembering the obscure ecology facts that appeared on the test… it was actually killer. most of the questions i missed were eco. gahh</p>

<p>the gastrointestinal cells question? was it an extensive matrix? other options were flagellated something, and a few more i can’t quite remember.</p>

<p>also what was the question about the organisms living at the bottom of the ocean with cold temps and little sunlight? that was the chemosynthesis one, right?</p>

282

<p>^Yes, producers were chemosynthetic bacteria. </p>

<p>Lol, I’m glad it wasn’t too detailed on molecular stuff. I hardly studied at all (just like 3 hours the night before). It wasn’t even as bad as I anticipated, because I went in there all unprepared haha.</p>

283

<p>Frig, I wrote phytoplankton for that one.</p>

<p>By my count, I’m at least -4/-5 so far.</p>

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<p>D: </p>

<p>Phytoplankton rely on photosynthesis.
It’s okay; I’m already down to -5 or 6. (2 or 3 wrong, 2 omit)</p>

285

<p>It’s so stupid, I completely focused on molecular biology since almost every single practice test is primarily on that. No damn study book has more than a chapter on ecology. But this test was almost completely ecology, which I totally hate as a subject anyway.</p>

286

<p>can someone explain why the pedigree question on free earlobes was 1/2? i put 3/4. :/</p>

287

<p>@3ntropy:</p>

<p>Free earlobes were dominant, and the connected? earlobes were recessive.</p>

<p>Female 1 was displaying the free earlobe trait, so she was expressing the dominant trait:</p>

<p>that means that her genotype was either FF or Ff (F being dominant and f being recessive). Both combinations would result in the expression of the dominant phenotype. </p>

<p>The question was asking for the percentage likelihood that the female was a heterozygote? (forget if it was hetero or homo lolz) Well either way, you’ve got 50% chance of the female’s genotype being either FF or Ff.</p>

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<p>but the question was asking for the probability that the offspring of that female and another recessive male would express the dominant trait (aka Ff or FF). and since female 1 could be either FF or Ff, the probability has to be greater than 50%, right?</p>

289

<p>What? I remember that question asking for the probability that Female 1 was a heterozygote (or homozygote wakeke). I don’t remember it being a long question, and I don’t remember any mention of offspring, or another recessive male.</p>

<p>Or this is another question… LOL</p>

<p>Okay let’s get the question straight first. XD</p>

<p>I remember the question that I am talking about was the very first question on that pedigree section. Are you talking about the same?</p>

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<p>haha no, it wasn’t the first question. it was something like the second last question on the pedigree. (:</p>

291

<p>Ahh okay. So that’s the question with the further generations and basing it on the offspring… I don’t really remember that question. If someone makes it clear probably we could figure it out :3</p>

292

<p>oh about the first question - i thought that the probability of the female being heterozygote was 100%, since her partner also expressed the dominant trait but one of their offspring was recessive in phenotype.</p>

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<p>HAHAHA OMG. Suicide. I hope I’m remembering wrong.</p>

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<p>The free earlobe one is 1/2 b/c the mother expressed dominance, but mated with a homozygous recessive male and still produced ONE non-expressing offspring (They clearly had a recessive male son). If she was homozygous, that wouldn’t have been possible.</p>

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<p>who here agrees, the curve has to be good…</p>

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<p>@mowmow721</p>

<p>i thought she was mated with a male who expressed the dominant phenotype? in that case both genotypes would have to be Ff in order to get an ff offspring. therefore she HAS to be heterozygous. probability 100%.</p>

297

<p>unless i misread the diagram :S how many recessive kids were there in total? and in which generations?</p>

298

<p>jakeiscool, I think that the curve will be decent. This test definitely seemed to have some random questions that were not covered in any review book I used (Barron’s and PR).</p>

299

<p>to make the pedigree question clearer…</p>

<p>i THOUGHT it looked like this:

<a href=“http://i35.■■■■■■■.com/sexh02.jpg[/IMG]”>http://i35.■■■■■■■.com/sexh02.jpg

</a></p>

<p>and the two questions were, respectively:

  1. the probability that individual X is heterozygous, and
  2. the probability that offspring ? exhibits the dominant phenotype. (shaded = dominant phenotype)</p>

<p>tell me if i’m wrong D:</p>

300

<p>this pedigree question was in M right?!?</p>