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Edexcel A2 Biology Unit 5 (6BIO5) - 22/06/2011- OFFICIAL THREAD ! watch

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    Am I right in thinking that Mantyranta's mutation meant epo receptors didn't shut down epo production? But that the gene therapy mentioned in 'Secret Weapon' is talking about inserting the gene for the production of epo?

    I don't fully understand how this would work as if the athlete still had normal epo receptors would this not turn off the production of epo when oxygen levels are normal?
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    Here we are talking about the initiation of the transcription of a gene which makes Epo. So the receptor would be ineffective to stop it. I think it would only inhibit Epo production in normal circumstances....


    J
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    due a mutation his epo receptors did not shut down, which was a good mutation for him!becuase normally when oxgen levels are normal the receptor will shut down the epo production , I think his EPO receptrs remained open all the aim hence the crucial feedback was not truned on, when the level of oxgyen was high or low!
    (Original post by lbavfc)
    Am I right in thinking that Mantyranta's mutation meant epo receptors didn't shut down epo production? But that the gene therapy mentioned in 'Secret Weapon' is talking about inserting the gene for the production of epo?

    I don't fully understand how this would work as if the athlete still had normal epo receptors would this not turn off the production of epo when oxygen levels are normal?
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    June 2010 question paper and marking scheme please?
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    Could someone explain how phytochromes and IAA work and what is the difference?

    thanks
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    (Original post by ethiokid)
    Could someone explain how phytochromes and IAA work and what is the difference?

    thanks
    hey
    u got 2 types of phytocromes
    red and far red
    Pr and Pfr
    Pr absorbs red light and change form to Pfr
    while Pfr absorbs far red light and change form to Pr
    Pr stimulate flowering in Long Day Plant
    inhibits flowering in Short Day Plant
    Pfr stimulate flowering in Short Day Plant
    inhibit flowering in Long Day Plant
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    (Original post by Parthenon93)
    June 2010 question paper and marking scheme please?
    \


    here u go
    mark scheme is too big because it has all papers sorry
    Attached Images
  1. File Type: pdf 6BI05_01_que_20100625.pdf (393.2 KB, 109 views)
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    guys... do we have 2 know all practicals? or just unit 5 ones??
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    Hiya,
    I am only revising the Unit 5 ones....


    JP
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    (Original post by abuelzouz)
    guys... do we have 2 know all practicals? or just unit 5 ones??
    I don't see why we would need the old ones just stick to unit 5, in the past we've never needed the old ones. And I don't see how they could come into the synoptic nature of the exam.
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    Hi guys, if someone has a minute and has done the specimen paper, could you explain why on the radioactive nucleotide question (9bi), that the recognition sequence for EcoRI appeared 3 times in the piece of DNA?


    http://store.aqa.org.uk/qual/gce/pdf...5-W-SQP-07.PDF

    thanks
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    Could someone please answer question 5 c) i) from the Jan 2011 paper? I have been looking at it and just cannot see it... it might just be me being incredibly stupid!!

    Thanks!
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    I haven't even seen the Jan Paper - can't access it - can you send me a link to it please?cheers!
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    Here you go
    Attached Images
  2. File Type: pdf 6BI05_01_que_20110309.pdf (183.6 KB, 87 views)
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    iM ILL AND THE COLD IS DEVELOPING TODAY HOW CAN I TAME THIS COLD AND CRAM FOR THE EXAM TOMORROW?
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    (Original post by xshopoholicx)
    iM ILL AND THE COLD IS DEVELOPING TODAY HOW CAN I TAME THIS COLD AND CRAM FOR THE EXAM TOMORROW?
    Read topic 7's spread on Immune system, those macrophages will be right on it
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    (Original post by Choca Mocha)
    Could someone please answer question 5 c) i) from the Jan 2011 paper? I have been looking at it and just cannot see it... it might just be me being incredibly stupid!!

    Thanks!
    The markscheme says this:
    1. oxygen {to oxidise hydrogen / as hydrogen
    acceptor / as final acceptor of electron transport
    chain} / eq ;
    2. reference to reduced {coenzyme / NAD / FAD /
    eq} ;
    3. (reduced coenzyme) from {glycolysis / Krebs
    Cycle / eq} ;
    4. comparison of two {oxygen uptake /
    respiration rates} from pyruvate, molecules B
    and C e.g. respiration rate faster in pyruvate
    than molecule B ;
    5. reference to uptake of substrate compared
    e.g. uptake of molecule B faster than
    molecule C ;
    6. comparison of diffusion rate / molecular size
    / eq ;
    7. comment on oxidation level of substrate e.g.
    ratio H:O in molecule /eq ;
    8. relative quantity of {reduced coenzyme / eq}
    produced / eq ;
    9. pH effect of pyruvate more favourable for
    {enzyme / reaction} / eq ;
    10. number of carbon atoms of {C lower than B} /
    eq ;
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    (Original post by Choca Mocha)
    Here you go
    Thanks for this

    Looked at the question. It's not easy is it! i think it is to do with the bacteria having to take in more o2 for respiration. With lactic acid they will need max amount of O2 to convert it back to pyruvate.
    Using pyruvate as a substrate they would need less O2 than with the lactic acid as there is no oxygen debt. Seeing as pyruvate immediately enters the krebs cycle and is oxidised in to FAD and NAD. So the molecules B and C could perhaps be Oxygen or water?

    Hope i haven't confused the issue even more...
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    (Original post by katie_katie_katie)
    The markscheme says this:
    1. oxygen {to oxidise hydrogen / as hydrogen
    acceptor / as final acceptor of electron transport
    chain} / eq ;
    2. reference to reduced {coenzyme / NAD / FAD /
    eq} ;
    3. (reduced coenzyme) from {glycolysis / Krebs
    Cycle / eq} ;
    4. comparison of two {oxygen uptake /
    respiration rates} from pyruvate, molecules B
    and C e.g. respiration rate faster in pyruvate
    than molecule B ;
    5. reference to uptake of substrate compared
    e.g. uptake of molecule B faster than
    molecule C ;
    6. comparison of diffusion rate / molecular size
    / eq ;
    7. comment on oxidation level of substrate e.g.
    ratio H:O in molecule /eq ;
    8. relative quantity of {reduced coenzyme / eq}
    produced / eq ;
    9. pH effect of pyruvate more favourable for
    {enzyme / reaction} / eq ;
    10. number of carbon atoms of {C lower than B} /
    eq ;
    OK I think it's safe to say i would have got no marks for that question!!haha
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    (Original post by Jennie_pro)
    Thanks for this

    Looked at the question. It's not easy is it! i think it is to do with the bacteria having to take in more o2 for respiration. With lactic acid they will need max amount of O2 to convert it back to pyruvate.
    Using pyruvate as a substrate they would need less O2 than with the lactic acid as there is no oxygen debt. Seeing as pyruvate immediately enters the krebs cycle and is oxidised in to FAD and NAD. So the molecules B and C could perhaps be Oxygen or water?

    Hope i haven't confused the issue even more...
    ahhh okay thank you!
 
 
 

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