<p>Is it true that if you get all the MC questions right, or around 90% of them correct, then you are guaranteed a 5 even if you get 0's on all the FRQ's?</p>
<p>Yes that is true. Because if you get most of them correct, you automatically have enough raw points to get a 5 even without the essays.</p>
<p>For the chi-swuare, they will give you the formula. Since no calculators are allowed, they give you easy numbers to work with. I'm sure its the same for Hardy-Weinberg. And to clear things up, the exam is most def. 100 questions in 80 minutes, They changed it a few years back, I believe.</p>
<p>No, the thing with all questions right and no FR is a guaranteed 5 is incorrect. At least with the old format (119 questions on 2002 AP since #61 was not scored).</p>
<p>If you get all MC right and no FR right, then that is an 89.99999. You need a 90 for a 5 on that exam (2002).</p>
<p>Ok guys plzzz.
I don't understand two major concepts currently. I don't understand water pontential AT ALL (no where in the PR book). I don't get chi squares (i read the description someone posted... but I didn't understand much....). Can someone help me?</p>
<p>In genetics, variation may be due to one of the following:
Law of segregation- alleles segregate independently
Law of Independent Assortment- chromosomes assort independently of each other during metaphase I or metaphase II
Random fertilization- which gametes meet to form zygote is a random event
All the above are due to chance.</p>
<p>As we increase the sample size we expect that are observed results approach our expected results (applying the laws of probabilities)</p>
<p>In analyzing results from genetic experiments we need to test the significance of the deviation between the observed and the expected results. (i.e. are they just random events due to chance OR is there something else causing them?)</p>
<p>Chi Square:</p>
<p>1.We define the Null Hypothesis= There is NO significant difference between observed and expected values. Any difference is due to chance.
2.We can either :
a.Reject Null- deviations are NOT due to CHANCE (there is something else causing it)
b.Fail to reject- the deviation is PURE CHANCE</p>
<p>To determine the value of the deviation we do a Chi-Square (2 )
2 = (o-e)2
Σ -----<br>
e
o = observed value
e = expected value
Σ = sum of values
degrees of freedom=
number of categories(number of phenotypes) minus 1.
Example: if have 2 phenotypes ( short and tall) there is only 1 degree of freedom.
If have 4 phenotypes such as in a dihybrid cross then there are 3 degrees of freedom.</p>
<p>We can use a table that gives Chi square values with respect to degrees of freedom and derive the probability that the deviation is due to CHANCE.
Note in Chi Square analysis the probability value is defined as the “probability that the deviation is due to CHANCE)<br>
By Convention: if P is less than 5% we REJECT NULL- the deviation is not due to chance. If P is greater than 5% we fail to reject the Null therefore the deviation is due to chance.</p>
<p><a href="http://rvgs.k12.va.us/statman/Table-C.jpg%5B/url%5D">http://rvgs.k12.va.us/statman/Table-C.jpg</a></p>
<p>Water Potential= Pressure potential + solute potential</p>
<p>The more solute, the more negative solute potential. The more pressure pushing water INTO the area, the more negative pressure potential.</p>
<p>Something with a very negative potential will have water move into it.</p>
<p>So how does this relate to plants intake of water? thanks for this info though. It helped a lot.</p>
<p>In the root of the plant, it needs to obsorb water.
The water potential is negative on the inside compared to the water potential in the soil therefore water moves into the root.</p>
<p>Guys, how deep is the material on the AP Bio test? I have a feeling my teacher really overtaught, i.e. we had to learn every individual step of respiration and photosynthesis and be able to recognize every intermediate compound by their molecular structures.</p>
<p>Also, do we need to know about the respiration of fats and proteins? Or the hexose monophosphate shunt?</p>
<p>Arti: While you do need to know every step of photosynthesis and respiration you will not need to know compounds by molecular structure other than to identify if something is a card, lipid, protein, or nucleic acid. You don't need to know the two things at the bottom, I've never even heard of them!</p>
<p>carb rather than card lol</p>
<p>I think art also meant that his teacher made him memorize the like 9 steps of glycolysis. The answer is no. Just be able to recognize whats going on if you see a diagram like it on the test.</p>
<p>in junctions between cells, which is used for communication?</p>
<p>i always learned that desmosomes were communication and that gap junctions were used for transport of materials, is this correct? because i'm confused on what my review book is saying.</p>
<p>We'd only need to get about 90 mc right to get a 5? That seems like a little too easy for people.</p>
<p>its even less than 90 (out of 100). you need about 60-65% of the total points on the exam to get a 5.</p>
<p>It's probably not less than 90 because you have to multiply a number (ex. .75 to the 120 MC before) to diminish the MC portion for it to account for only 60 percent of the test...</p>
<p>there are only 100 mc.</p>
<p>what raw score mc do you need? 75ish right?</p>
<p>Nobody knows since we only have scoring rubrics from AP exams of previous years which have 120 or 119 MC questions.</p>
<p>To get a 5, you need about 60% of all available points (after subtracting 1/4 for every wrong) on the old exam. Say I got 112 right and 8 wrong, then that's about 82.5 since you multiply by ~0.75. There are 4 FR. Each is out of 10. Add up all the FR points and multiply by 1.5. Add this number to your MC score. 90 and above is a 5.</p>