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

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    (Original post by LaurenLovesMaths)
    For the question about the carrier protein Y and its other function, did anyone else write about it being an enzyme? I know it sounds weird to have enzymes in the cell surface membranes of cells, but substrate went in to Y and then cellulose came out??
    That question really confused me too. I couldn't tell which direction the cellulose was moving and didn't really understand what they were asking - same for the last question.
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    (Original post by memoriial)
    That question really confused me too. I couldn't tell which direction the cellulose was moving and didn't really understand what they were asking - same for the last question.
    Yeah it was a confusing question, and I completely ran out of time so answered the whole of Q9 in like 5 minutes (I didn't even have time to read the passage )
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    (Original post by LaurenLovesMaths)
    Yeah it was a confusing question, and I completely ran out of time so answered the whole of Q9 in like 5 minutes (I didn't even have time to read the passage )
    I read the passage like ten times and didn't understand any of it. Tbh I think it didn't help I was so exhausted from the first half of the paper plus I had another exam in the morning, and all the exam stress.. urgh.
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    (Original post by memoriial)
    I read the passage like ten times and didn't understand any of it. Tbh I think it didn't help I was so exhausted from the first half of the paper plus I had another exam in the morning, and all the exam stress.. urgh.
    Aw no I'm begging for the grade boundaries to drop, and hopefully they will because it's a new spec
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    Is anyone able to put together an unofficial mark scheme by any chance? Thanks!
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    (Original post by LaurenLovesMaths)
    Is anyone able to put together an unofficial mark scheme by any chance? Thanks!
    i can put one together :s of what i wrote but ill need urm the questions reminder lol :s
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    (Original post by Asad_2015)
    i can put one together :s of what i wrote but ill need urm the questions reminder lol :s
    I don't have the questions I'm afraid
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    (Original post by LaurenLovesMaths)
    For the question about the carrier protein Y and its other function, did anyone else write about it being an enzyme? I know it sounds weird to have enzymes in the cell surface membranes of cells, but substrate went in to Y and then cellulose came out??
    I think it like was also an enzyme and it catalysed the condensation reaction of beta-glucose molecules into cellulose
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    Unoffical Markscheme (can't remember all questions)

    Magnification = x21000
    Matrix was pointing to the cristae.
    Microscopic property was 3D (black and white might not have been a valid answer as this wouldn't be able to differentiate it from TEM)

    Draw a tangent for the gradient and calculate the value, i got something like 13... i think can't remember this.

    Calorimeter question: Measure intensity with colour change and use known concentrations, repeat the experiment and see what intensity is shown, correspond this to time. (not sure)

    Divide values by 60 in table and you get S shape curve with days on x axis and rate on y (x10^-3)

    DNA: Enzyme = HIV, Cell wall = Bacterium, Capsid = HIV, RNA = HIV.

    DNA strand acts as a template stand where free nucleotides in the cell complementary bases join on to due to complementary base paring. Hydrogen bonds are formed and A binds to T, G bind to C.

    The protein in membrane, combines the cellulose chains together to make microfibrils for cell use such as cell wall.

    Endopeptidase is a secretes which breaks them in centre to form smaller peptides (in exam i wrote exo lol XD but its endo)

    using the drug will stop a enzyme working to as of complimentary shape hence dangerous.

    Mutation cause change in base sequence of the enzyme therefore primarry peptide sequence changed therefore the tertiary structure changed therefore enzyme no longer complementry therefore no e-s complex formed.

    90 water, 10 concentration, measuring using volumetric cylinder ( in exam i wrote the other way around as silly error XD)

    drug is competitive inhibitor and has a complementary shape which induce fits and reducs no of e-s complex forming, therefore reduces rate.

    Yes and no. Using 0-10 cont of solution is not helpful as not enough monospidle division seen, 100 is good as 93% is seen however 7% can re replicate and this will still be a potential harm to person. 1000 mol is an overdose and riduculous so the student should redo experiment with value ranging from 100 to 1000 to find perfect amount. He can not be certain with data given.

    Monospindles will not cause identical daugther cells forming as one cell will have full chromosomes and one none, this is due to the fact that the chromessomes will not be split at the centremore and go to each pole of cell, all chromosomes will go to one side only.

    evidence of membrane is due to protein present and phosphate groups pointing in and outwards.

    The girl will take a dead pathogen which will trigger primary immune respose. T cells activate B cells which have presented the pathogen antigen on there surface by forming antigen-antibody complexes, B cells form memory cells, hence secondary immunity next time. I did talk about phagocytes a bit too but thats relevant this question was about the memory cells.

    The sucrose and days interpretation question annihalated me XD

    ADT + Pi --> condensation reaction + atp synthase.

    2 doses of vaccine i wrote ( not sure :s)
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    (Original post by LightAtTheEnd)
    I think it like was also an enzyme and it catalysed the condensation reaction of beta-glucose molecules into cellulose
    I really hope so because that's what I put!! Thank you
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    (Original post by LaurenLovesMaths)
    I don't have the questions I'm afraid
    put answer together for u \ not all right idk XD
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    (Original post by Asad_2015)
    Unoffical Markscheme (can't remember all questions)

    Magnification = x21000
    Matrix was pointing to the cristae.
    Microscopic property was 3D (black and white might not have been a valid answer as this wouldn't be able to differentiate it from TEM)

    Draw a tangent for the gradient and calculate the value, i got something like 13... i think can't remember this.

    Calorimeter question: Measure intensity with colour change and use known concentrations, repeat the experiment and see what intensity is shown, correspond this to time. (not sure)

    Divide values by 60 in table and you get S shape curve with days on x axis and rate on y (x10^-3)

    DNA: Enzyme = HIV, Cell wall = Bacterium, Capsid = HIV, RNA = HIV.

    DNA strand acts as a template stand where free nucleotides in the cell complementary bases join on to due to complementary base paring. Hydrogen bonds are formed and A binds to T, G bind to C.

    The protein in membrane, combines the cellulose chains together to make microfibrils for cell use such as cell wall.

    Endopeptidase is a secretes which breaks them in centre to form smaller peptides (in exam i wrote exo lol XD but its endo)

    using the drug will stop a enzyme working to as of complimentary shape hence dangerous.

    Mutation cause change in base sequence of the enzyme therefore primarry peptide sequence changed therefore the tertiary structure changed therefore enzyme no longer complementry therefore no e-s complex formed.

    90 water, 10 concentration, measuring using volumetric cylinder ( in exam i wrote the other way around as silly error XD)

    drug is competitive inhibitor and has a complementary shape which induce fits and reducs no of e-s complex forming, therefore reduces rate.

    Yes and no. Using 0-10 cont of solution is not helpful as not enough monospidle division seen, 100 is good as 93% is seen however 7% can re replicate and this will still be a potential harm to person. 1000 mol is an overdose and riduculous so the student should redo experiment with value ranging from 100 to 1000 to find perfect amount. He can not be certain with data given.

    Monospindles will not cause identical daugther cells forming as one cell will have full chromosomes and one none, this is due to the fact that the chromessomes will not be split at the centremore and go to each pole of cell, all chromosomes will go to one side only.

    evidence of membrane is due to protein present and phosphate groups pointing in and outwards.

    The girl will take a dead pathogen which will trigger primary immune respose. T cells activate B cells which have presented the pathogen on there surface by forming antigen-antibody complexes, B cells form memory cells, hence secondary immunity next time. I did talk about phagocytes a bit too but thats relevant this question was about the memory cells.

    The sucrose and days interpretation question annihalated me XD

    ADT + Pi --> condensation reaction + atp synthase.
    Thank you!!
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    Thankyou, what was the question about Alzheimer's, and why people were allergic to the vaccine?

    Also, the question about the explanation of the graph. Something like why sucrose affected the growth?
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    (Original post by RIDDHI7)
    Thankyou, what was the question about Alzheimer's, and why people were allergic to the vaccine?

    Also, the question about the explanation of the graph. Something like why sucrose affected the growth?
    you mean why the drug was dangerous? or the graph of which dose was better? i said two doses were better :s not sure
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    (Original post by RIDDHI7)
    Thankyou, what was the question about Alzheimer's, and why people were allergic to the vaccine?

    Also, the question about the explanation of the graph. Something like why sucrose affected the growth?
    About the sucrose graph, it's fairly complicated.
    On the Y-axis, you have your rate of hydrolysis of sucrose and on the X-axis, you have your time.
    So the gradient of this graph tells you the (bear with me here) RATE of the RATE of hydrolysis of sucrose.
    Now just the RATE of hydrolysis of sucrose tells you how fast the sucrose is broken down into its monomer units (glucose and fructose). The glucose is used in the process of photosynthesis I believe. So the if the RATE of the RATE of hydrolysis of sucrose is higher, the rate of production of glucose is higher. Hence more photosynthesis can occur?
    Therefore the gradient of that curve told you the rate of growth.
    Between the first 4 days growth was occuring, but at a relatively slow rate. Between days 4 to 10 the growth was faster. In the final 2 days (10-12) the rate of hydrolysis of sucrose remained constant and therefore there was no growth.
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    any predictions on the grade boundaries?
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    (Original post by dragonblazer11)
    any predictions on the grade boundaries?
    Maybe a little lower than usual as it's a new spec. I'm hoping they drop loads but I doubt it
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    (Original post by memoriial)
    I read the passage like ten times and didn't understand any of it. Tbh I think it didn't help I was so exhausted from the first half of the paper plus I had another exam in the morning, and all the exam stress.. urgh.
    I felt exactly the same like feeling that exhaustion also the fact I had an exam
    In the morning too

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    (Original post by LightAtTheEnd)
    About the sucrose graph, it's fairly complicated.
    On the Y-axis, you have your rate of hydrolysis of sucrose and on the X-axis, you have your time.
    So the gradient of this graph tells you the (bear with me here) RATE of the RATE of hydrolysis of sucrose.
    Now just the RATE of hydrolysis of sucrose tells you how fast the sucrose is broken down into its monomer units (glucose and fructose). The glucose is used in the process of photosynthesis I believe. So the if the RATE of the RATE of hydrolysis of sucrose is higher, the rate of production of glucose is higher. Hence more photosynthesis can occur?
    Therefore the gradient of that curve told you the rate of growth.
    Between the first 4 days growth was occuring, but at a relatively slow rate. Between days 4 to 10 the growth was faster. In the final 2 days (10-12) the rate of hydrolysis of sucrose remained constant and therefore there was no growth.
    Isn't glucose used in respiration and only produced in photosynthesis - thus as less sucrose is hydrolysed, less glucose available for respiration and therefore less growth?
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    Seeing as that paper seemed to focus on a handful of topics, what are everyone's predictions for paper 2?
    I noticed there wasn't anything on gas exchange, digestion & absorption, taxonomy...
 
 
 
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