AQA BIOL4 ~ 11th June 2013 ~ A2 Biology

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.

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?

Did you firm Bham?


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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!!!

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/AQA-BIOL4-W-QP-JAN11.PDF

It would be net - resp = gross because you take it away from both sides to get gross by itself

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/AQA-BIOL4-W-QP-JAN11.PDF

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

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 20^oC 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

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

what did you get at a level if you dont mind me asking?

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?