<p>@ChessNBio By over and over i mean like maybe 4-5x while taking notes and making connections. @botherme how much of Raven’s Biology of Plants and Albert’s Molecular Biology should i study to be prepared for the Open and Semifinal round?</p>
<p>Dude, just prepare as much as you can. It doesn’t help to set a quota for the amount that you’re planning on studying. Just study as much as you can, but I recommend all of Raven’s, maybe read over Alberts once(I haven’t even read Albert’s, just going off on what other people are saying sorry), Open round, campbell would probably suffice.</p>
<p>A. Oleaceae
B. Brassicaceae
C. Solanaceae
D. Fagaceae
E. Liliaceae </p>
<ol>
<li><p>Plant I: Ca4 Co4 A4+2 G2</p></li>
<li><p>Plant II: T6 A6 G3</p></li>
<li><p>Plant III: Ca4 Co0 A4 G0</p></li>
</ol>
<p>Do they really expect us to know this? </p>
<p>How high do we need to get on semis to make USABO? I know they take top 20, but is there a certain cutoff score that usually means you made camp if you got it? </p>
<br>
<br>
<p>@ Audrae: it varies a lot from year to year. Different exams, different competitors, etc. Generally, a qualifying score is nowhere near 100% though.</p>
<p>@ Chess: Yes, flower families (and formulas) are fair game. At the semifinals level, I might avoid explicitly using flower formulas, but something like “Which of these families has predominantly monoecious imperfect flowers” would be fine. And that question would absolutely show up on Finals (and to a very good approximation, has).</p>
<p>@ botherme re: this question: “In questions 42 to 44, you have two true-breeding strains of pea plants with white flowers. Crossing these two strains yields an F1 generation that only has purple flowers. Self-crossing these purple flowered plants yields the following ratio of progeny with purple and white flowers: 9 purple: 7 white.”</p>
<p>This is where pattern recognition helps with genetics questions. This is a classic 9:3:3:1 ratio - what you get when you cross two double heterozygotes.</p>
<p>P1: AAbb and aaBB (true breeding, apparently you need A<em>B</em> to be purple)
F1: AaBb (all of them)
F2: 9 A<em>B</em> : 3 A<em>bb : 3 aaB</em> : 1 aabb (9 purple : 7 white)</p>
<p>From there, you can figure out pretty easily what fraction of the purples are AABB and AaBb.</p>
<p>@ all re: Alberts: it’s overkill. The techniques chapter is worth seeking out; the cell biology parts may be worth a once-over, but aren’t a high priority; the physiology parts (second half of the book iirc) are just too detailed to be useful.</p>
<p>Read Campbell until you’re well and truly done with it. Then read Raven’s Plant, and then read Campbell some more until it starts to haunt your dreams. Then go for the more specialized texts. A first-year undergrad genetics book (any one will do) will have practice problems; it’s less important that you read the text, but it takes practice to develop the sort of pattern recognition described above. Then get a human physiology book (I have Vander’s). There are a lot of med students and premeds writing questions. Then get a first-year ethology textbook and give it a once-over; there’s a small set of canonical examples and major experiments that show up over and over, and you will see them here. Then start practicing your dissection and pipetting skills for camp, because you <em>are</em> going to camp at that point. And only then, if you’re truly still bored out of your wits, read Alberts. (And if you’re still bored after that, read a biochem textbook…and if you’re still bored, can I hire you?)</p>
<p>wow, I can’t believe I missed that DX Thanks so much</p>
<p>By the way, I’ve got a genetics handout I made for camp in 2006. If you can do this, you’re ready for almost any pedigree question we would dare throw at you.</p>
<p><a href=“File:Kaull evil pedigree.pdf - OpenWetWare”>http://openwetware.org/wiki/Image:Kaull_evil_pedigree.pdf</a></p>
<p>wow, that handout seems really helpful. Would you be able to post an answer sheet so we can check our work? Thanks
Or did anyone else get answers so I can compare?</p>
<p>Also, I was going over plant stuff and now I’m not so sure that ranunculus was the right answer bean. It has water crowfoots, too, which are adapted to water. Are you sure the answer wasn’t ananas since the suckers are modified stems? I know that the leaves of ananas are slightly adapted, but it seems like the least extreme of the options.</p>
<p>.</p>
<p>genetics hand-out from blueroses67 - my answers:
A. recessive autosomal
B 1/288
C. 1/144
D. not really sure</p>
<p>A. Same
B. Same
C. Man i was an idiot. I see what i did wrong now.
D. 1/80</p>
<p>I redid it and got 1/128</p>
<p>What did you do wrong @botherme ?</p>
<p>You guys have A so far…good job. =P (And possibly another. 1/128th is indeed one of the answers.)</p>
<p><em>grabs popcorn</em></p>
<p>I’m not sure if I understand question 46 from the 2012 semifinals. I get A - 1/8 by ignoring the fact that all of the child’s siblings are affected. However, since the question explicitly says “given that that the other five children in Generation IV do not have hemophilia,” shouldn’t the probability take that into account? I’m not sure how to do this calculation, but I feel that the child’s unaffected siblings should make it less likely that the mother is a carrier, and thus decrease the affected individual’s probability of having hemophilia.</p>
<ol>
<li>The following pedigree depicts inheritance of hemophilia, an X-linked recessive disorder. The great-grandfather of the child marked with “?” suffered from hemophilia. Assume the great-grandmother has no past history of hemophilia, and could not have been a carrier of the disease. What is the probability that the child marked with “?” will be born male AND suffer from hemophilia given that that the other five children in Generation IV do not have hemophilia?</li>
</ol>
<p>A. 1/8 B. 1/10 C. 1/12 D. 1/20 E. 1/32</p>
<p>B.1/192 forgot to factor in the fact that they are twins
C.1/128 the fact that someone got hemophilia in that generation means that those twins have to both be carriers</p>
<p>D. The coefficient of relatedness was 1/16, which means that the risk to Lauren has to be less than 1/80 doesn’t it?</p>
<p>@ Radulae
You don’t get # 46? How about # 45 before it?</p>