2012 USABO Thread

<p>For those that are interested the fill-in chart from the second question in Part C is word for word from pg.987 of the 8th edition of Campbells Biology.</p>

<p>Here is another question</p>

<p>Which of the following are common precursors in hormone synthesis?</p>

<p>I put carbohydrates, fats, and polypeptides. However another choice was carbohydrates, polypeptides and steroids. Which one would be more correct?</p>

<p>Carbohydrates are not precursors for animal hormones. I think the correct answer was something like polypeptides, steroids, and amino acids.</p>

<p>How about the question where it says that a researcher removed some liquid from all of a earthworm’s body segments. I put that there would be normal contraction but not full extension.</p>

<p>Also what else would an animal have if is has an excretory system with blind-ended tubules emerging as outgrowths in the digestive system, is terrestrial and has an open circulatory system. I put that it would have nephridia.</p>

<p>When comparing the mammal’s respiratory system with the arthropod’s tracheal system, which of the following is false?</p>

<p>I put “both systems possess invaginated surfaces”.</p>

<p>What did you people put for the dideoxy chain termination question where it said that ddGTP was not added. I put that the spectrogram would show gaps</p>

<p>Ok, there’s quite a lot of questions to get started with. Originally i didn’t remember many, but this kinda jogged my memory. If any of my answers seems wrong then somebody (darksigma?) please correct me or argue the point. Histidine was the shuttling amino acid (it has an imidazole ring that carries hydrogens). </p>

<p>I think SDS for the PAGE one, although i may have put something else.</p>

<p>Definitely, hydrophobic interactions.</p>

<p>The muscle one I don’t see a right answer among the five… look at pg. 1111 in Campbell’s which says oxidative fibers have many mit, rich blood supply, are slow twitch and fast twitch, but nothing about fat.</p>

<p>The earthworm one i think there would be no contraction and no extension due to no hydrostatic pressure exerted by the fluid.</p>

<p>The extra feature of the described organism is a tracheal system because it’s an arthropod (malpighian tubules, open circ, etc.)</p>

<p>Don’t remember choices to the respiratory one. The spectrogram one might have been gaps, not sure what i put.</p>

<p>For the PAGE one, I think it’s a reducing agent. In molecular techniques, you usually use reducing agents to break disulfide bridges (which are used in teritiary and quaternary structures). Since they wanted to break the protein into two separate subunits, it seems appropriate that reducing agents are used to break bonds that hold those units together. </p>

<p>For muscle, storing fat is correct. The purpose of the question was to test if you know the difference between glycolytic (mostly fast-twitch) and oxidative (mostly slow-twitch) muscle fibers. Since oxidative fibers mainly utilize cellular respiration, it seems right to me that they store much more fat (beta oxidation) to generate ATP. </p>

<p>There was one question about lenticels in Part B, I think I chose three answers that said 1) lenticels are unique to angiosperms 2) form by rupturing phelloderm 3) originate in plant epidermis…</p>

<p>Any ideas?</p>

<p>Also, there was a question about “snonting” (two-part question).
I think I put “males snont more when there are more males around that are similar in age”
For the kin selection, I put 12.5% but I think it’s 6.25%</p>

<p>@ onthemoon</p>

<p>I may be wrong but don’t muscles normally use glucose, not fat.</p>

<p>You are right about the reducing agent.
According to Wikipedia: Besides the addition of SDS, proteins may optionally be briefly heated to near boiling in the presence of a reducing agent, such as dithiothreitol (DTT) or 2-mercaptoethanol (beta-mercaptoethanol/BME), which further denatures the proteins by reducing disulfide linkages, thus overcoming some forms of tertiary protein folding, and breaking up quaternary protein structure (oligomeric subunits). This is known as reducing SDS-PAGE, and is most commonly used.</p>

<p>Apparently “An orchid growing epiphytically on a tree is an example of inquilinism”. I just looked it up.</p>

<p>Also what did you put for the question that asked about the problems plants didn’t face when they moved from an aquatic environment to land?. I put pollen production since pollen production came much later in geologic time.</p>

<p>@emblem101 </p>

<p>Using our friend wikipedia, here’s the final info:
“Muscles are predominantly powered by the oxidation of fats and carbohydrates, but anaerobic chemical reactions are also used, particularly by fast twitch fibers. These chemical reactions produce adenosine triphosphate (ATP) molecules which are used to power the movement of the myosin heads.”
since fast twitch muscle predominantly uses glycolysis, it wouldn’t store as much fat as the slow-twitch muscle. Also, fatty acids are converted to acetyl CoA which cannot be used for gluconeogenesis.</p>

<p>Ok, what about the question where it said which of the following animal groups is least related to the other? The answer choices were Annelida, Aschelminthes, Arthropoda, Echinodermata, Mollusca.</p>

<p>Probably Echinoderms…I put aschelminthes but since echinoderms are only deutrostomes among the choices, they would be least related to others…</p>

<p>For the chi-square test did you put acceptable or unacceptable or insufficient data?</p>

<p>“If you were to stimulate a resting state axon halfway along its length, what would happen?”
I put that chloride ions will pass from the outside of the axon to the inside.</p>

<p>@emblem101: Inquilism only applies to animals. The correct answer is adventitious roots.</p>

<p>@tigertwist: Are you sure about your answer, because wouldn’t the presence of more fluid mean there’s a stronger hydrostatic skeleton for muscles?</p>

<p>Also, I put gaps for the dideoxy chain termination one, reducing agent for the subunits one, and echinoderms for the phylogeny one.</p>

<p>For the axon one, I think it’s “the potential will conduct to and away from the cell body” or sth like that. I have a website that asks a similar question: [U&lt;/a&gt; of M - Dept. of Physiology](<a href=“http://physiology.med.umn.edu/courses/phsl3061/studyq02.html]U”>http://physiology.med.umn.edu/courses/phsl3061/studyq02.html)
question#6</p>

<p>Yeh you are right about the orchid question since according to ehow, There are some 20,000 to 25,000 species of orchids in the plant family Orchidaceae. Some orchids grow from tubers or spreading rhizomes under the ground while other species climb up trees or live in them. Species of climbing orchids and orchids that live in trees, called epiphytic orchids, grow adventitious roots. </p>

<p>“Which of the following roles have humans not traditionally taken in the process of domesticating animals?”
A. Parent in imprinting
B. Nature in selection
C. Dominant male in social organization
D. Landmark in social learning
E. Bottleneck effects</p>

<p>How about the Hardy-Weinberg equilibrium question about the Sentinelese tribe and eye color when explorers come from the outside world. I put 4,000 for that question.</p>

<p>Also what about the USDA and the monoculture of plants where they were left alone and formed a new species. The two most likely answers were that “speciation can be explained by the fact that the plants are polyploids” and “the original species first evolved polymorphism and then each formed a separate species”</p>

<p>“Identify primary ions involved in each process”
A) Ca+2
B) K+
c) Both
d) neither</p>

<p>1) Long term potentiation by NMDA receptor
2) slow block to polyspermy
3) Saliva secretion
4) Mechanotransduction in hair cells</p>

<p>I put A, C, C, C as answers…</p>