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AQA BIOL4 ~ 11th June 2013 ~ A2 Biology

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    (Original post by Farid1)
    I wondering whether you have to answer the 5-markers at the end in a certain order. For example, if the 5-marker is about speciation and so to explain and describe geographical isolation does it matter what order you make your 5 points in or does it have to be in the correct order for you to get the 5 marks.
    I'm pretty sure it doesn't - but just make sure it makes sense and points link onto eachother to ensure no confusion. Usually marks are only awarded for stuff in the right context though so just write it as if you're being marked for written communication and you should be okay
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    (Original post by Tikara)
    then start!!! there must just be mainly resits unfortunately so not as much activity

    but it's safe to say I no longer worry about the 6/5 markers at the end of biol4 now I know of the unholy 25 mark essay at the end of biol5

    My main tips would be 1. look at the amount of marks given! It'll indicate how much the question wants and I ran out of time when I did the exam because I gave giant answers for 3 markers

    and 2. read that darn question carefully!!! I know it seems obvious but the wording of every question is specific to get certain bits of information out of you!

    also, how is every one gonna do the questions at the end? are you gonna do them first and then the exam or the other way round?
    definately starting with the 5 markers. My problem last unit was that i left the 5 markers till last, so i had to do all three within about 7 minutes. Not gonna do that again!
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    (Original post by lcj0503)
    Did you firm Bham?


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    haha yes
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    (Original post by Tikara)
    Okay, just had a look at this one and it isn't too hard - I'm not really sure when this is taught in Biol4 though

    but anyway, the growth rate is going to be the gradient in the line, which is change in y / change in x, or change in mass / change in age.

    The maximum growth rate is therefore when the line is the steepest, when there is the greatest rise in mass in the shortest rise in age. Usually with questions like these there will be a two points at nice places just hitting on the grid exactly.

    So I picked the points at 20 and 22.5 days on the dotted line as they're on the steepest part of the curve (you could pick two points at anywhere on this steepest line and get the same answer but I chose these cause they're easier) and the change in mass is 100 so 2.5/100 = 40mg/day

    TL;DR points at 20 and 22.5 days --> 22.5/100 = 40

    hope that helped mate
    That's great! Thanks so much!!!
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    (Original post by sals1234)
    That's great! Thanks so much!!!
    lmao I'm glad it did - but I just need to point out that I was incredibly tired while writing that and I've got the numbers the wrong way round

    change in y / change in x <--- this is correct so I should've written 100/2.5 = 40 :P I did this in my calculator and wrote it down wrong haha (also the tldr should be 100/2.5 aswell)
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    (Original post by Tikara)
    lmao I'm glad it did - but I just need to point out that I was incredibly tired while writing that and I've got the numbers the wrong way round

    change in y / change in x <--- this is correct so I should've written 100/2.5 = 40 :P I did this in my calculator and wrote it down wrong haha (also the tldr should be 100/2.5 aswell)
    please can you help me on Q4b? I thought net prod = gross + resp, therefore net + resp = gross, but i get the wrong answer ... please help!!
    http://filestore.aqa.org.uk/subjects...W-QP-JAN11.PDF
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    (Original post by master y)
    please can you help me on Q4b? I thought net prod = gross + resp, therefore net + resp = gross, but i get the wrong answer ... please help!!
    http://filestore.aqa.org.uk/subjects...W-QP-JAN11.PDF
    It would be net - resp = gross because you take it away from both sides to get gross by itself
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    (Original post by k1rby)
    It would be net - resp = gross because you take it away from both sides to get gross by itself
    oh sorry i wrote it wrong its meant to be net = gross - resp... doesnt work!
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    (Original post by master y)
    please can you help me on Q4b? I thought net prod = gross + resp, therefore net + resp = gross, but i get the wrong answer ... please help!!
    http://filestore.aqa.org.uk/subjects...W-QP-JAN11.PDF
    haha literally just on this question mate, I'll be a sec
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    (Original post by master y)
    oh sorry i wrote it wrong its meant to be net = gross - resp... doesnt work!
    Wait are you linking the right question? 4b on the jan11 is about toads getting more prey to eat as there are less of them
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    (Original post by Tikara)
    Wait are you linking the right question? 4b on the jan11 is about toads getting more prey to eat as there are less of them
    ahh another mistake again... i mean 5b!!
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    Anyone know what the three 5 markers will be on?

    I think eutrophication, light independent reaction and saprobiotic bacteria
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    (Original post by master y)
    ahh another mistake again... i mean 5b!!
    Yeah you have the right idea on this one - I think it's just annoying working out two different graph ranges and noticing that there is only one respiration line.

    anyways, looking at 20oC medium light intensity, the net rate of photosynthesis looks to be just above 2.4 (so like 2.41/2.42)

    and then looking at the dotted photosynthesis line at the same temp, and using the values on the right - the rate of respiration is around 0.35 (little bit above like 0.36)

    using net = gross - resp. losses and rearranging to net + resp. = gross
    you get 2.42 + 0.36 = 2.79

    The answer in the mark scheme allows anything in the range: 2.75 (2.4 + 0.35) to 2.81, so theres a little bit of wiggle room in rounding as the lines aren't nicely hitting the grid.

    Hope that helped mate
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    am I the only one who is beginning to love the 5 markers? No silly aqa HSW or weird ambiguous graphs, just straight forward knowledge
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    (Original post by Tikara)
    Yeah you have the right idea on this one - I think it's just annoying working out two different graph ranges and noticing that there is only one respiration line.

    anyways, looking at 20oC medium light intensity, the net rate of photosynthesis looks to be just above 2.4 (so like 2.41/2.42)

    and then looking at the dotted photosynthesis line at the same temp, and using the values on the right - the rate of respiration is around 0.35 (little bit above like 0.36)

    using net = gross - resp. losses and rearranging to net + resp. = gross
    you get 2.42 + 0.36 = 2.79

    The answer in the mark scheme allows anything in the rante: 2.75 (2.4 + 0.35) to 2.81, so theres a little bit of wiggle room in rounding as the lines aren't nicely hitting the grid.

    Hope that helped mate
    thanks but for the respiration graph... when 20 degrees, the rate seems more like 0.7! am i being stupid here...
    by the way what did you get overall for that paper? i got 53
    edit: ohhhhhh im looking at the wrong axes! thanks aanyway
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    (Original post by Tikara)
    am I the only one who is beginning to love the 5 markers? No silly aqa HSW or weird ambiguous graphs, just straight forward knowledge
    Not posted here before but I'm re-sitting to try and boost my A2 UMS, and yes, I love the 5 markers too, I hate having to try and guess the marks schemes for the HSW questions etc...unfortunately I dropped 6 marks on the three 5 markers in january, but we'll skip over that fact :P
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    (Original post by laser174572)
    Not posted here before but I'm re-sitting to try and boost my A2 UMS, and yes, I love the 5 markers too, I hate having to try and guess the marks schemes for the HSW questions etc...unfortunately I dropped 6 marks on the three 5 markers in january, but we'll skip over that fact :P
    what did you get at a level if you dont mind me asking?
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    (Original post by master y)
    what did you get at a level if you dont mind me asking?
    I've not finished A2 yet, I just need as much UNS as possible to try and get an A* for my offer


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    Question 7 is always the death trap for me, just did the Jan12 paper and got 58 is that any good? (I was losing marks on like every question again on stuff I knew but just didn't know I was supposed to say grr) Whats the boundaries usually like for an A does any one know?
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    (Original post by Tikara)
    Question 7 is always the death trap for me, just did the Jan12 paper and got 58 is that any good? (I was losing marks on like every question again on stuff I knew but just didn't know I was supposed to say grr) Whats the boundaries usually like for an A does any one know?
    just had a look and apparently thats an A* !? lmao thats silly low, losing 21 marks and you can still get an A* - in edexcel exams you can only lose about 4

    well I guess this kinda makes up for the stupid confusing wording of the questions and silly graphs. Anyone know how to get full UMS then?
Updated: November 14, 2013
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