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AQA AS Biology 7401/1 and 7401/2 Exam - 26th May and 7th June 2016 Watch

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    What did you guys put for the question about what would you control in the experiment it was 2 marks.
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    (Original post by rosemondtan)
    Wrote 40:11 because I didn't feel like rounding up haha
    I thought you had to make a ratio to 1 in bio but oh well we have the same ratio just in slightly different forms
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    Anyone got a list of topics or questions that came up? I need reminding to check my answers
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    (Original post by SM-)
    For precautions when measuring FEV I put:
    1 make sure they each either do not take an extra breath in or breath in as much as they can before breathing out
    2 make sure you get people in same health, condition etc
    For HIV why scientists got that conclusion I put that there may be little cases of infection in Europe and little deaths from HIV and AIDS
    What do you guys think?
    I said like find people with an equal mix of male and female and use a large sample size to avoid sampling bias. The thing about health conditions though, you can't actually find people with the same condition because you're looking for smokers and non-smokers and they have different ailments? That's what I thought at least. But first point sounds valid!
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    (Original post by AfcFob)
    I thought you had to make a ratio to 1 in bio but oh well we have the same ratio just in slightly different forms
    I believe that as long as the ratio is the same, there is no reason why _:1 is preferred over whole numbers!
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    (Original post by Abirella)
    What did you guys put for the question about what would you control in the experiment it was 2 marks.
    Size of the disks and how much disinfectant they were soaked in but idk if that is right lol
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    (Original post by Abirella)
    That's true, however at our sixth form if we fail the AS in the subject we cannot take it for A2.
    Ahh I understand. That's the same criteria for us, we have to achieve at least a D. Fingers crossed ayeee
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    (Original post by Salamandastron)
    Size of the disks and how much disinfectant they were soaked in but idk if that is right lol
    OHHH I think I just threw away 2 marks I put temperature and concentration how stupid am I.
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    (Original post by Will_Evans)
    Anyone got a list of topics or questions that came up? I need reminding to check my answers
    •digestion - name one other enzyme that hydrolyses proteins as well as endopetidases and exopeptidases,explain why it is more efficient to used both endopetidases and exopeoptidases instead of just exopeptidases, then there was the question on amino acids and how the respiratory inhibitor can prevent amino acids for being transported

    •hiv and AIDS- how a gene can cause a mutation in the protein receptor and how this mutation can help prevent hiv,how they reached the conclusion about the statement about the mutation and hiv

    •movement in the phloem-about the plant stem and how sugars move around it

    •biological molecules-carbohydrates and how starch and cellulose structure relates to its function

    •lungs-fev and how this drop when a person reached 30 years of age that had to be described by using ventilation ,why you calculated the mean for FEV and why low FEV leads to disability

    •osmosis-about how sea water effects the water potential of the worm

    •Haemoglobin- how the worms saturation and partial pressure of oxygen allowed it to stay alive in polluted waters

    •the cardiac cycle- Working out heart rate and stroke volume

    All the ones I can remember that are not in the correct order can anyone add
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    (Original post by Shaks.smxth)
    Ahh I understand. That's the same criteria for us, we have to achieve at least a D. Fingers crossed ayeee
    Yeah same! I just hope there's an happy end like a fairytale but sadly life is not a fairytale it is real anything could happen lol
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    (Original post by rosemondtan)
    I believe that as long as the ratio is the same, there is no reason why _:1 is preferred over whole numbers!
    True... At the end of the day we have exactly the same numbers so it won't matter that much
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    (Original post by rosemondtan)
    Exact same answer holler!!
    I wrote phosphate bonds contain alot of energy which are broken and down so that energy is realeased...


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    (Original post by rafiuddin)
    people with HIV can still have babies (despite the parent not being naturally selected)
    people with HIV can survive under medical/quarantine conditions (probs wrong)
    I said:

    1. Maybe the data showed there were very few HIV infections in the past, hence very low selection pressure for the CCR5 mutation
    2. Lack of correlation between number of HIV infection and frequency of CCR5 mutation in population

    What do you guys make of that?
    Thanks
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    (Original post by Abirella)
    Oh are you sure? I think we don't have to mention the stomata as it said that other than the stomata explain 2 features .... but you are right I guess with your explanation. I think this could be a seperate point.
    Lol I really am not sure... we all know how fickle biology mark schemes can be, they're unpredictable
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    (Original post by omer_bawa)
    I wrote phosphate bonds contain alot of energy which are broken and down so that energy is realeased...


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    Tf is a phosphate "bond", surely you mean the element

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    (Original post by Hello_246975)
    That's exactly what I put, but it could also be with the sewage that causes the W.P in the rivers to be lowered (more -ve). Therefor in the sea water may enter and cause cells to burst? I'm just wondering about the context we had to answer that question in.
    I said that seawater has a higher water potential so water moves into the worm and causes its cells to burst :/ but everyone on here is saying the opposite
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    My mind went black as soon as I opened the paper - endopeptidase and exopeptidase. :/ my answer was protease, as was most of my classes' >.<
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    (Original post by rosemondtan)
    1. Mutations are completely random and not caused by anything (I think the question didn't suggest that it was random so)

    2. Maybe HIV cases were low so there was in fact little or no selection pressure

    Idk lol I didn't like this question
    HIV only developed about 100 years ago when SIV (HIV for monkeys/simians essentially) jumped species and was transferrable to humans. I wrote how this is not enough time for natural selection to have an effect. It was a weird question and if I'm right, I don't see why they would ask a general knowledge/history question in a biology exam.
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    (Original post by LaurenLovesMaths)
    I said that seawater has a higher water potential so water moves into the worm and causes its cells to burst :/ but everyone on here is saying the opposite

    Tbh your answer would make more sense in the context they provided, because knowing that sea water contains salt is general knowledge ( not something everyone may know), so if people don't know that sea water contains salt they wouldn't know that the water potential is slightly lower (more negative) whereas the question already stated there was sewage in the water, so basically they told us that the river water had a lower water potential (more negative), and asked what would happen to the worm in the sea. So water would move in and burst cells. Water moves from high WP (sea) to low WP (cells)

    But I recon if enough people put both, the markscheme might accept either
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    (Original post by Abirella)
    That's true, however at our sixth form if we fail the AS in the subject we cannot take it for A2.
    Same. but only way youd fail is if you get ALOT of questions wrong. And you could easly tell if you had. Alll my firends who have failed in AS's knew as soon as they came out :lol:
 
 
 
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