<p>So I was reviewing for USABO, and stumbled over some of the trickier ones - ones that can't be answered by a thorough reading of Wikipedia and ones that I do not know the answer to. Any help to be had?</p>
<hr>
<p>Kidneys provide osmoregulation for the body. Consumption of which nutrient creates the greatest need for osmoregulation?</p>
<p>Cellulose
Fat
Oil
Protein
Starch</p>
<p>I'm thinking either protein or starch? Cellulose is indigestible, and oils and fats would not produce much need for osmoregulation as they would be immediately stored and/or used for beta-oxidation. My choice would be protein, as it is metabolized to toxic ammonia/urea.</p>
<p>Other questions soon to come, I'm sure. :P</p>
<p>oh shoot, I just realized I've been bumping the thread. I'll stop now.</p>
<p>Which of the following marine communities would be LEAST affected by a volcanic eruption or meteor impact that injected enough debris into the atmosphere to reduce sunlight by 50% for two years?</p>
<p>Benthic community
Coral reef community
Deep sea vent community
Estuary community
Pelagic community</p>
<p>Obvious answer is deep sea vents? None of the others work. However, many deep sea vent communities thrive on organic detrius that falls down from above as well as chemosynthetic bacteria… but this effect would most likely be minor… perhaps I’m overthinking it.</p>
<p>first: I agree protein
second: I agree placenta, marsupials and monotremes are mammals.
third: benthic is ocean floor though, and neither really use sunlight…</p>
<p>The thing that makes me sway towards deep-sea vents is that they actually have producers in the form of chemosynthetic bacteria that can use the sulfur and iron for energy. It actually gets pretty extreme: [Giant</a> tube worm - Wikipedia, the free encyclopedia](<a href=“http://en.wikipedia.org/wiki/Giant_tube_worm]Giant”>Riftia - Wikipedia)</p>
<p>Benthic would be a good answer, though. I’ll read more about it.</p>
<p>edit: it appears that the benthic zone is at the bottom of anything. So the benthic zone of a shallow lake would still depend on photosynthesis and sunlight. I guess that makes the deep-sea vents the best answer?</p>
<p>I edited my last post. I believe it is deep-sea. I just remember reading somewhere that deep-sea depends partially on debris as well. <em>shrug</em></p>
<p>Okay, I don’t think I’m reading this problem correctly.</p>
<p>The Hardy-Weinberg equilibrium principle assumes all of the following statements EXCEPT:</p>
<p>The proportion of alleles in a population tends to remain stable
The frequencies of dominant and recessive alleles for a given trait in a gene pool of a large population can bedetermined mathematically
Genotype frequencies in a large population are unaffected by Mendelian segregation and recombination of alleles
For a given trait the frequency of dominant alleles is greater than that of recessive alleles
For a given trait the frequency of the genotype of the heterozygous population can be determined mathematically</p>
<p>The fourth one? Is it really as obvious as I think it is?</p>
<hr>
<p>You extract RNA from liver cells and then carry out an agarose gel electrophoresis of the liver RNA. The RNAfragments are then transferred to an RNA-binding membrane (nitrocellulose or nylon) using capillary action. Next, youhybridize a probe for gene X to the RNA on the membrane. Which of the following statements regarding yourexperiment is true?</p>
<p>You are trying to determine how many copies of Gene X are in liver cells
You are trying to determine if the Gene X protein is present in liver cells
You are trying to determine if Gene X is expressed in liver cells
You are trying to determine the chromosomal location of Gene X
You are trying to determine whether Gene X has a mutant sequence</p>
<p>Again, the fourth one, yes?</p>
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<p>Which of the following is NOT a second messenger?</p>
<p>Calcium ion
Magnesium ion
Diacyl glycerol
Inositol trisphosphate (IP3)
Cyclic AMP</p>
<ol>
<li>agreed</li>
<li>I’m pretty sure its the 3rd. RNA = expression, and you are probing for RNA levels.</li>
<li>Magnesium, the others are all important 2nd messengers.</li>
</ol>
<p>Secondly, there are papers exploring the effect of Mg2+ as a second messenger that are not from Japan that date back to 1995. I’d expect that CEE would have known about something that happened nine years ago.</p>
<p>“The two most widely used second messengers are cyclic AMP and calcium ions” (215) & “The pathways leading to calcium release involve still other second messengers, inositol trisphosphate (IP3) and diacylglycerol (DAG).” (217)</p>
<p>Quoted directing from Campbells. 2004 means they must have been using what 6th edition? Came out 2001. + 10 years for editing.</p>
<p>In superoxide dismutase 1, a copper ion is bound to the active site and is important for
enzyme activity. In this enzyme, copper most likely functions as a(n)
A. coenzyme<br>
B. allosteric activator<br>
C. allosteric inhibitor
D. cofactor </p>
<p>The answer is apparently cofactor, but isn’t coenzyme the more precise choice?</p>