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    I personally thought the reaction was limited by the temperature of 20 degrees, seeing as it was a human enzyme (and they normally function at 37 degrees). They wouldn't be bothered by pH seeing as they are adapted for acidic conditions.
    Also, anybody got a legit unofficial markscheme for this or anything? The F321 resit for chemistry already has pics of the paper up haha
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    (Original post by hugo13)
    Hajj Mubarakah!
    I wish I did!!😂 people call me Haj short for Hajra 😂😂
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    Basically nobody seems to have a mark scheme (but if you do post it for god sake haha)
    so I'm just going to write down what I can remember. If I forget a question please feel free to add/ask to this post. Here goes:

    1
    - The mitochondria had circular DNA, similar to prokaryotic calls.
    - The measurement question you had convert your measurement from mm to micrometers then use image/mag to get its size (I wanna say it was 8.2 micrometers but I really don't remember).
    -Mitochondria are the site of aerobic respiration and produce ATP for active transport and protein synthesis.
    -Crista, matrix

    2
    - The human trypsin question. SO you had your stock answer of complimentary, E-S complex, active site structure etc.
    -Fatty acids (COOH) were release by hydrolysis, increasing acidity.
    -Curve sketched dropped less and plateaued further along.
    -I think either the pH change changing the active site causing inhibition, or the fact that a human enzyme was being used at 20 degrees would have been appropriate to explain the curve. All active sites were filled. I can't remember exactly what I wrote.
    -pH meter was more precise because it used quantitative data as opposed to just changing colour.

    3
    -Heart stuff was straight forward. I think it was C & A but again I can't remember the diagram.
    -The hole between the ventricles would have cause O2 to diffuse across ventricles, meaning that less O2 was saturated in the blood which was pumped around the body. I think some people chose to talk about pressure instead which I think would have also been valid.
    (I honestly cannot remember the other hear questions so let me know)

    4
    - During expiration the diaphragm relaxes and domes upwards, reducing the volume of air in the lungs and increasing the pressure in the lungs so that air was forced out (because pressure was less in air outside the body)
    -FEV decrease over 5 years regardless of age but those who smoked exhibited a greater decrease.
    -Alveoli ruptured decreasing surface area for diffusion. Fibrous scar tissue lengthened the diffusion pathway. Reduced elasticity cause lower elastic recoil. All factors reduced conc. gradient between blood and alveoli, reducing diffusion.

    5
    - Lactose (the most ****ing moronic test ever).
    - They consumed the dairy in the morning so they could be awake to score their symptoms.
    - Subjects should've avoided eating dairy as this would've affected results .
    - Avoid bias
    - Lactose-free milk had been treated with lactase.
    - The scoring system was subjective. No repeats. Only small amount of dairy ingested (like 240cl or something **** like that) so symptoms not severe.
    - Data... (I can't remember. Bloating was bad but I can't remember exactly what I wrote.

    6
    -I think it was the liver (or pancreas... **** knows I'm too busy studying for Chemistry).
    Anyway. The protease being inactive withing the cell means it won't hydrolyse the cells own tissues. Something about how the RER being the organelle involved in protein synthesis although I can't remember if ribosomes were actually the right answer.

    7
    - Ebola. This is the one I don't remember most.
    There was mention of antigenic variability so vaccines would be ineffective as the antigens would've changed.

    8
    (I know this was really question 8... so I've mixed stuff up a bit. BUT THIS IS WHY WE NEED A MARKSCHEME HAHA!)

    (Simplified versions of what I wrote).

    -Okay so glucose and sodium bind and move into the epithelial cell from the small intestinal lumen using by co transport via a channel.
    -Sodium is actively transported out using ATP against a conc' gradient, into the blood stream.
    -This maintains the concentration gradient between the lumen and the cell causing more sodium and glucose to enter.
    -Glucose enters the blood via facilitated diffusion.

    -Cl- ions use facilitated diffusion to cross plasma membrane (using water filled channel protein) as Cl- is polar so it is repelled by the phosphate on the phospholipid bilayer. Down a diffusion grad. etc. High to low.
    - O2 is non-polar so PO4 doesn't repel so it can diffuse through the membrane along a conc. grad by simple diffusion.

    Hope this helped. Please if anyone has an actually decent markscheme, potential grade boundaries, remembers questions I can't or wants to share what they answered, please do.

    All the best
    All
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    (Original post by Ordo)
    **THIS IS ONLY FOR ALEVEL BIOLOGY UNIT 1 - RESIT - NOT NEW SPECIFICATION**
    Hi Im new to this and I cannot find any thread for this one so I decided to create one. Anyways how you guys feeling about this exam? Please share revision tips and feel free to ask questions and post whatever you like here as long as it is related to this one.

    Here are some revision notes I find useful:
    - Mr Pollock - YouTube
    - VBiology - http://vbio.weebly.com/aqa-unit-1-revision-pack.html-
    https://docs.google.com/folder/d/0B8...dmd6Mjk3WVRLZw - (I found this somewhere from this website)

    Good luck
    Basically nobody seems to have a mark scheme (but if you do post it for god sake haha)
    so I'm just going to write down what I can remember. If I forget a question please feel free to add/ask to this post. Here goes:

    1
    - The mitochondria had circular DNA, similar to prokaryotic calls.
    - The measurement question you had convert your measurement from mm to micrometers then use image/mag to get its size (I wanna say it was 8.2 micrometers but I really don't remember).
    -Mitochondria are the site of aerobic respiration and produce ATP for active transport and protein synthesis.
    -Crista, matrix

    2
    - The human trypsin question. SO you had your stock answer of complimentary, E-S complex, active site structure etc.
    -Fatty acids (COOH) were release by hydrolysis, increasing acidity.
    -Curve sketched dropped less and plateaued further along.
    -I think either the pH change changing the active site causing inhibition, or the fact that a human enzyme was being used at 20 degrees would have been appropriate to explain the curve. All active sites were filled. I can't remember exactly what I wrote.
    -pH meter was more precise because it used quantitative data as opposed to just changing colour.

    3
    -Heart stuff was straight forward. I think it was C & A but again I can't remember the diagram.
    -The hole between the ventricles would have cause O2 to diffuse across ventricles, meaning that less O2 was saturated in the blood which was pumped around the body. I think some people chose to talk about pressure instead which I think would have also been valid.
    (I honestly cannot remember the other hear questions so let me know)

    4
    - During expiration the diaphragm relaxes and domes upwards, reducing the volume of air in the lungs and increasing the pressure in the lungs so that air was forced out (because pressure was less in air outside the body)
    -FEV decrease over 5 years regardless of age but those who smoked exhibited a greater decrease.
    -Alveoli ruptured decreasing surface area for diffusion. Fibrous scar tissue lengthened the diffusion pathway. Reduced elasticity cause lower elastic recoil. All factors reduced conc. gradient between blood and alveoli, reducing diffusion.

    5
    - Lactose (the most ****ing moronic test ever).
    - They consumed the dairy in the morning so they could be awake to score their symptoms.
    - Subjects should've avoided eating dairy as this would've affected results .
    - Avoid bias
    - Lactose-free milk had been treated with lactase.
    - The scoring system was subjective. No repeats. Only small amount of dairy ingested (like 240cl or something **** like that) so symptoms not severe.
    - Data... (I can't remember. Bloating was bad but I can't remember exactly what I wrote.

    6
    -I think it was the liver (or pancreas... **** knows I'm too busy studying for Chemistry).
    Anyway. The protease being inactive withing the cell means it won't hydrolyse the cells own tissues. Something about how the RER being the organelle involved in protein synthesis although I can't remember if ribosomes were actually the right answer. Peptide bond.

    7
    - Ebola. This is the one I don't remember most.
    There was mention of antigenic variability so vaccines would be ineffective as the antigens would've changed.

    8
    (I know this was really question 8... so I've mixed stuff up a bit. BUT THIS IS WHY WE NEED A MARKSCHEME HAHA!)

    (Simplified versions of what I wrote).

    -Okay so glucose and sodium bind and move into the epithelial cell from the small intestinal lumen using by co transport via a channel.
    -Sodium is actively transported out using ATP against a conc' gradient, into the blood stream.
    -This maintains the concentration gradient between the lumen and the cell causing more sodium and glucose to enter.
    -Glucose enters the blood via facilitated diffusion.

    -Cl- ions use facilitated diffusion to cross plasma membrane (using water filled channel protein) as Cl- is polar so it is repelled by the phosphate on the phospholipid bilayer. Down a diffusion grad. etc. High to low.
    - O2 is non-polar so PO4 doesn't repel so it can diffuse through the membrane along a conc. grad by simple diffusion.

    Hope this helped. Please if anyone has an actually decent markscheme, potential grade boundaries, remembers questions I can't or wants to share what they answered, please do.

    All the best
    • Thread Starter
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    Thanks but i wouldn't worry too much about it. People should able to read all answers in previous pages.

    And move on to unit 2 if you are resitting -
    http://www.thestudentroom.co.uk/show....php?t=4122319
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    (Original post by hugo13)
    They call me Hugo, short for Abdul ofc 😂 Gotta pretend to be a gora on here to be taken seriously ygm! What course u applying for Hajz?
    Aaah okay nice to meet you "Hugo"😂😂 I've applied for Optom 😊
    What have you applied for?
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    (Original post by haj101)
    Aaah okay nice to meet you "Hugo"😂😂 I've applied for Optom 😊
    What have you applied for?
    Pharmacy at Aston what uni? How'd I just know you'd either say Medcine, optom or pharmacy LOL This is my 3rd A level year lmao
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    (Original post by hugo13)
    Pharmacy at Aston what uni? How'd I just know you'd either say Medcine, optom or pharmacy LOL This is my 3rd A level year lmao
    Either Manchester or Bradford- they're closest to home😊 LOOOL maybe because I'm Asian 😂 Aaah same im on a gap year too hopefully all goes well for you iA
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    Does anyone know where I can find the unofficial markschneme?

    Posted from TSR Mobile
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    Posted from TSR Mobile

    What u guys think the grade boundaries will be?
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    (Original post by EmmaHarvard)
    Posted from TSR Mobile

    What u guys think the grade boundaries will be?
    well last year it was like 43 for an A but this year, most candidates who sat the exam were A2 students but not all.
    This paper was a little harder than last years in general but the main thing is that the students who sat it would be either one of two types:

    - People who realised they messed up royally last year, got their act together and performed well in this test

    - Or people who never learn and have left studying for this exam to the last minute yet again and have subsequently done poorly.

    All this in mind. I'm gonna say around 45 minimum, 50 maximum for an A.
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    (Original post by EmmaHarvard)
    Posted from TSR Mobile

    What u guys think the grade boundaries will be?
    Probably 46-47 for an A, 54-55 for full UMS.
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    (Original post by FraserK)
    Would I be punished for referencing glycoproteins rather than antigens? .... as they were referring to glycoproteins on the HIV surface.
    No I don't think you will be, I did the same and referred to glycoproteins. Because i did a past paper and the Q was about proteins on the surface of chlamydia. And in the mark scheme they wrote protein/antigen. Its the June 2011 paper.
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    Was the inhibitor and breathing one three markers?
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    (Original post by EmmaHarvard)
    Was the inhibitor and breathing one three markers?
    Yep, free 6 marks!


    Posted from TSR Mobile
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    (Original post by Bennyab)
    Yep, free 6 marks!


    Posted from TSR Mobile


    Posted from TSR Mobile

    And the first ebola question?
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    For the question where you had to tick boxes, what did you tick for the bacteria? I wasn't sure whether to tick 'cell surface membrane' or not 'cause I know they have membranes but it's not technically on the surface because of the cell wall, right?
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    (Original post by TayaP)
    For the question where you had to tick boxes, what did you tick for the bacteria? I wasn't sure whether to tick 'cell surface membrane' or not 'cause I know they have membranes but it's not technically on the surface because of the cell wall, right?
    You wouldnt tick the cell surface membrane, although i did and realised it was wrong after
    • Thread Starter
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    (Original post by Username_12345)
    You wouldnt tick the cell surface membrane, although i did and realised it was wrong after

    All cells have a cell surface membrane. I think it went like this:
    From Flagellum, cell surface membrane, (nucleus or mitochondria):
    Human cell - no, tick,tick
    Bacteria - tick tick, no
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    (Original post by Ordo)
    All cells have a cell membrane. I think it went like this:
    From Flagellum, cell membrane, (nucleus or mitochondria):
    Human cell - no, tick,tick
    Bacteria - tick tick, no
    I know they have a cell membrane, but it specifically said cell-surface :/
 
 
 
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