<p>Also, what is the difference between protein and steroid hormones? That was the only part of the first FRQ that I could not answer…</p>
<p>^ steroid hormones directly diffuse through the plasma membrane, while protein hormones require signal-transduction pathways because of their size and characteristics.</p>
<p>what if you said proteins diffuse across the membrane and steroids need receptor-mediated endocytosis for FRQ #1?</p>
<p>@Notreal-Would not be correct because most proteins are too large to go through the plasma membrane (some can) but they are also, if i remember correctly, hydrophilic so they cannot pass the membrane. Steroid hormones don’t go through receptor-mediated endocytosis, they simply pass through the membrane. I think this information is correct, but if not, someone please correct me. And are we allowed to talk about the frq?</p>
<p>The third FRQ ate my soul. I knew a genetics kind of problem would be coming up, but when I saw it I freaked out, botched my first answer, freaked out some more, and just wrote some key word BS to get a few pity points, haha. The hormone one and enzyme lab were super easy; the fourth one was a bit hard because I didn’t pay as much attention during ecology and crap, but I managed to get an alright answer in.</p>
<p>^I failed miserably at that too. I just stated the obvious on every part and moved on…</p>
<p>On the protein/steroid hormone question, I got the protein part right, but I had no clue on the steroid hormone, so I just spent a paragraph detailing the structure of a steroid :)</p>
<p>wat is the cutoff going to be for a 5? any ideas for the cutoff based on previous years?</p>
<p>80-90 I’m assuming</p>
<p>Damn, I think I just contradicted myself in the first FRQ.</p>
<p>I mentioned the how hydrophilic vs. hydrophoic + diffusion/receptor protein things and how steroids would directly affect transcription facts,etc. Then I kinda panicked because I thought by “Compare” they meant to point out the similarities only.</p>
<p>That’s when everything got convoluted.</p>
<p>The FRQ were pretty easy…
I answered every subquestion of every free response except for one subquestion on number 1 referring to hormone and steroid receptors</p>
<p>xxrunningonempty- I think for the proteins they wanted you to talk about how the proteins are made up of amino acids and amino acids are really long, charged chains and therefore can’t get through the membrane. For starch, they are made of fats and so they are nonpolar and can get through the membrane. I THINK, that’s what I put.</p>
<p>What was the answer to 3B and 4B?</p>
<p>^ They’re discussed either somewhere in this thread, or in this thread: <a href=“http://talk.collegeconfidential.com/ap-tests-preparation/926406-ap-biology-post-exam-discussion.html[/url]”>http://talk.collegeconfidential.com/ap-tests-preparation/926406-ap-biology-post-exam-discussion.html</a></p>
<p>yea i switched protein and steroid for 1c. I mean I had the details, like receptor-mediated endocytosis, but then I said the steroid goes to the nucleus to activate cellular changes, while at the same time mentioning cAMP. Then I said the protein would diffuse across the membrane and stimulate the nucleus to activate certain genes and enzymes. **would they give me points for at least giving the correct details?
**
According to Cliffsnotes AP Biology 3rd Ed pages 201-202:
“1. The hormone (usually a steroid) diffuses through the plasma membrane, through the cytoplasm, and into the nucleus. The hormone binds to a receptor protein in the nucleus. The receptor protein, in turn, activates a portion of the DNA that turns on specific genes.
2. The hormone (usually a peptide) binds to a receptor protein on the plasma membrane of the cell (receptor-mediated endocytosis). The receptor protein, in turn, stimulates the production of one of the following second messengers.
-Cyclic AMP (cAMP) is produced from ATP. Cyclic AMP, in turn, triggers an enzyme that generates specific cellular changes.
-Inositol triphosphate (IP3) is produced from the membrane phospholipids. IP3, in turn, triggers the release of Ca2+ from the endoplasmic reticulum, which, in turn, activates enzymes that generate cellular changes.”</p>
<p>so im just worried bout my score. does anyone know usually what the cutoff is going to be for a 5? last year was 85 and do you guys think it will be higher or lower thi syear?</p>
<p>
It’s probably going to be either higher or lower this year.</p>
<p>:p</p>
<p>probably harsher curve cuz most ppl say the test was easier than last years…><</p>
<p>oops ignore this</p>
<p>anyone took the late test?</p>
<p>so you guys think the curve is going to be harsher or better? haha im getting mixed answers. some people this years mc was easier and essays were harder because they were kind of specific this year.</p>