****AP BIOLOGY - POST-exam discussion*****

<p>^ Okay that’s good.</p>

<p>Ugh - were we supposed to mention the expected ratio? </p>

<p>^ I just said the expected ratio was the same for everything and that all numbers should have been equal so I don’t really know.</p>

<p>Basically…in 3b what happened was exactly what you should have expected…based on test crosses I and II, you could see that bronze eyes and stunted wings were dominant
so when you do a dihybrid cross with them…you’ll get the same results!
SO:
“true breeding” bronze eyes, stunted wings (true breeding means homozygous) which can be written like BBWW since bronze eyes and stunted wings are dominant
“true breeding” red eyes, normal wings would be written as bbww therefore
When you cross those (as it says in cross III) the F1 generation would all be bronze eyes and stunted wings (BbWw)…exactly what you should expect</p>

<p>Then it says you cross those with “true breeding” red eyes, normal winged flies (bbww)</p>

<p>Crossing BbWw with bbww is going to allow the expression of ALL genotypes as the chart shows haha
but since there were a lot more recessive alleles…there were a lot more recessive phenotypes as the chart shows</p>

<p>What did you guys title yours? I just used that trick from chemistry where you do Variable A vs. Variable B. Wasn’t sure what else would be an appropriate title.</p>

<p>What did you guys title yours? I just used that trick from chemistry where you do Variable A vs. Variable B. Wasn’t sure what else would be an appropriate title.</p>

<p>^
I titled mine ____ Reaction Rate. I can’t remember what the reactant/enzyme was called. xD</p>

<p>Another question - what about 2b - for stating reason(s) why the rate was leveling off?</p>

<p>My friend and I had two different things.</p>

<p>if there were more recessive alleles, wouldnt that have shown up in crosses I and II?</p>

<p>and LOL for the title I just wrote “Production of maltose by a-amylase over time”, didn’t know what was an appropriate title >_></p>

<p>…</p>

<p>and i said the rate leveled off because there was no more substrate for amylase to act on to break down.</p>

<p>Dillon, THANK YOU. Since I couldn’t figure out 3b, I just wrote that it confirmed my findings in Cases I and II. LOL That ought to get me a point or so. :stuck_out_tongue: (Because it’s right!.. right?).</p>

<p>I titled my graph the same thing as Artism. Also, I said the rate leveled off because the substrate (starch) was diminishing, and there were less molecules for the amylase to react with, causing the rate to slow down, etc.</p>

<p>what? lol no because you were only crossing homozygous dominant with homozygous recessive…which would make F1 ALL expressing the dominant trait</p>

<p>Basically…in 3b what happened was exactly what you should have expected…based on test crosses I and II, you could see that bronze eyes and stunted wings were dominant</p>

<p>^
I don’t get it. xD
It isn’t what you expected because the results didn’t match?</p>

<p>i meant in the actual first and second crosses. a monohybrid cross for eye color or wing type. If there were so many recessive alleles, why didnt it show up there?</p>

<p>^^ why would it be impossible? lol not at all! haha
if you do the punnet square correctly…you’ll get several (ww) or “ss” genotypes haha</p>

<p>the expected ratio was definitely 9:3:3:1 (crossin WwRrxWwRr)
therefore, they were linked .</p>

<p>

</p>

<p>That’s what my friend put down :(</p>

<p>So, maybe I’m wrong. I put that the enzyme were completely saturated with substrate at that point. Probably doesn’t make much sense come to think of it.</p>

<p>the expected ratio was definitely 9:3:3:1 (crossin WwRrxWwRr)
therefore, they were linked .
^
But you were crossing WwRr x wwrr</p>

<p>You’re so welcome! hahaha I get genetics :D</p>

<p>^^ why are you crossing two heterozygous??
it says the F1 were crossed with true breeding red eyes, normal wings
the F1 generation all had BbWw and true breeding red eyes, normal wings would be bbww
therefore: BbWw x bbww
lol</p>

<p>

Yeah, that doesn’t make any sense. The enzyme does its job, and then is free to bind with another substrate molecule. If you add more substrate, the reaction would occur faster (the opposite of leveling-off).</p>

<p>This is becoming really confusing with everybody posting within 2 seconds of each other. :stuck_out_tongue: For question #3, refer to Dillon’s ingenious post: <a href=“http://talk.collegeconfidential.com/1064860541-post183.html[/url]”>http://talk.collegeconfidential.com/1064860541-post183.html&lt;/a&gt;&lt;/p&gt;

<p>^ why thanks! :smiley:
and true on the multiple posts every two seconds lmao</p>