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    (Original post by Jitesh)
    I have to agree the questions weren't worded as well as they could have been but that's expected if they've got newer examiners for the new spec if the other ones are doing the resit papers still
    According to the uncompleted unofficial mark scheme, from all the people on here conferring answers and being quite harsh on my marking, I've dropped around 11 marks
    So 59/70, do reckon that'll be an A?
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    (Original post by brodingoson)
    According to the uncompleted unofficial mark scheme, from all the people on here conferring answers and being quite harsh on my marking, I've dropped around 11 marks
    So 59/70, do reckon that'll be an A?
    yeah, haven't heard of a biology AS paper asking for more than 80% for an A regardless of exam board/spec
    But it's hard to be certain as I felt with most of the MCQ you could get them with educated guesses and eliminating ones it couldn't be without much thought
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    (Original post by h3rmit)
    The questions for this one were fine, I think, only the specimens and practice papers were bad. Obviously, there's no official mark scheme, but these questions were pretty nice and specifc, with clear answers required and they jogged your mind well.
    Spoiler:
    Show
    If you'd revised, of course
    Sorry I should have made myself clearer, I did revise but not as extensively as I should have done (due to having so many other exams that were more important).
    I agree, some questions were clear, for example the root hair question clearly indicated an answer with reference to water potential was required, but others were vague (e.g the last question).
    It may just be that the last question has clouded my memory.
    But in my opinion the old system was far better as revision could be more structured and in depth because of the topics being split.
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    is there an unofficial mark scheme?
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    Predictions for depth based on what came up in breadth?
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    Hi what did people write for the respiring tissues question?
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    (Original post by millymolly123)
    Hi what did people write for the respiring tissues question?
    Just saying there was more co2 and outlining the bohr effect
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    (Original post by Jitesh)
    yeah, haven't heard of a biology AS paper asking for more than 80% for an A regardless of exam board/spec
    But it's hard to be certain as I felt with most of the MCQ you could get them with educated guesses and eliminating ones it couldn't be without much thought
    Thanks! and yeah i thought the MCQ's were really easy, the only tricky one was the diffusion of the artificial membrane one but got that in the end
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    (Original post by brodingoson)
    Thanks! and yeah i thought the MCQ's were really easy, the only tricky one was the diffusion of the artificial membrane one but got that in the end
    Which one did yhou go for? The one where the Benedict's was positive for extracellular? (C or B I think it was)
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    (Original post by Jitesh)
    Which one did yhou go for? The one where the Benedict's was positive for extracellular? (C or B I think it was)
    Yeah, I put C. I felt like on some questions towards the end you could put a lot of information down like for e.g. the question that asked why do actively respiring tissues have more oxygen going to them then resting tissues. Bc you've got a steep conc. gradient, oxygen disassociates more due to acidic conditions etc...
    But dunno whether the mark scheme is going to be really specific on they want bc there were a lot of valid answers for the questions
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    (Original post by Jitesh)
    Which one did yhou go for? The one where the Benedict's was positive for extracellular? (C or B I think it was)
    Most of my class think they've failed it completely, I don't know how bc it wasn't a hard paper at all was just a wee bit vague on what they wanted you to put down on some questions
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    (Original post by brodingoson)
    Yeah, I put C. I felt like on some questions towards the end you could put a lot of information down like for e.g. the question that asked why do actively respiring tissues have more oxygen going to them then resting tissues. Bc you've got a steep conc. gradient, oxygen disassociates more due to acidic conditions etc...
    But dunno whether the mark scheme is going to be really specific on they want bc there were a lot of valid answers for the questions
    Yeah I had to do it by a process of elimination for that MCQ because you couldn't confirm there were any sugars in the extracellular solution but you knew there wouldn't be any in the sausage thing

    A lot of questions were vague and it didn't seem like it was wanting something specific near the end
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    (Original post by Jitesh)
    Yeah I had to do it by a process of elimination for that MCQ because you couldn't confirm there were any sugars in the extracellular solution but you knew there wouldn't be any in the sausage thing

    A lot of questions were vague and it didn't seem like it was wanting something specific near the end
    Yeah haha that MCQ was the last question I did
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    (Original post by h3rmit)
    Just saying there was more co2 and outlining the bohr effect
    By outling bohr effect do you mean the release of hydrogencarbonate ions ect?
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    (Original post by Jitesh)
    What did your school give you?
    Did they print the spec off for you at least?
    We got the spec and a different textbook to what most schools got
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    (Original post by Hmb28)
    We got the spec and a different textbook to what most schools got
    Did they recommend buying the new spec. book?
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    (Original post by h3rmit)
    I think T killer cells produce perforin, it makes more sense that the killer cells actively produce substances to kill other cells
    That was just a mistake in my typing, it is the T killer cells that produce perforin
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    what did everyone say for the question that was like 'why don't erythrocytes make oxygen' something like that
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    (Original post by melissa-23)
    what did everyone say for the question that was like 'why don't erythrocytes make oxygen' something like that
    Was this the 'why don't erythrocytes use the oxygen they carry question?'
    I didn't really have a clue about it, but put something about they undergo very little metabolic processes and therefore don't require any energy, don't need to aerobically respire, so don't need oxygen.

    May be well off though! Anyone else got more of an idea?
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    (Original post by maxross)
    Was this the 'why don't erythrocytes use the oxygen they carry question?'
    I didn't really have a clue about it, but put something about they undergo very little metabolic processes and therefore don't require any energy, don't need to aerobically respire, so don't need oxygen.

    May be well off though! Anyone else got more of an idea?
    The question asked why doesn't erythrocytes use oxygen when transporting it, so i put...

    oxygen can only dissociate from the iron ions/haemoglobin sub-units when the haemoglobin is in acidic conditions which only occurs when carbon dioxide enters and causes the reactions with water etc. and the H+ ions diffusing back in, alternating the tertiary structure of haemolgobin (due to the low pH) in which oxygen is then released...
    So basically erythrocytes could not even use oxygen in the first place when carrying it due to low co2 and if they could use it, they'd only be able to use it when it disassociates to respiring tissues

    But i dunno, you're right as well but erythrocytes in fact they actually do use a fraction of the oxygen they carry, but very minuscule

    That's the problem with breadth is that you could say loads for the answer in which all answers would be valid, but they won't accept it
    (kinda rambled lol)
 
 
 
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