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    Anyone have any idea how much detail we need to know about the bread wheat? One textbook barely mentions it, and the other has a complete diagram of which species were interbred. Which one do we need to know?
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    geeeeee......This thread has some major progression.

    Can anyone tell me which past papers from the old spec are relevent to this unit?
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    (Original post by definite_maybe)
    Anyone have any idea how much detail we need to know about the bread wheat? One textbook barely mentions it, and the other has a complete diagram of which species were interbred. Which one do we need to know?
    With reference to bread wheat, you need to know the general idea that it was a wild species that gave rise to a sterile hybrid due to the homologous pairs unable to form during meiosis so couldnt form gametes. Then a mutation doulbed the chromosome number which allowed it to then breed with another species of wheat. Again sterile hybrid, mutation doubled the number of chromosomes and again leading to a hybrid which is hexaploid (6n chromosomes).

    This then means nuclei have to be bigger to store the extra chromosomes, thus cells are bigger.

    The bread wheat species has a characteristic called polyploidy which allosw it to contain more than one set of diploid chromosomes in its nuclei.

    They are then bred to produce more desirable traits, such as resistance to stem bending due to wind and rain, drought, pest and herbicide resistances etc.

    I dont think you need to know the in-depth species names etc of the wheat itself.
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    Omg just did my F212 resit..
    thank God it's over is all im saying now im back on this thread.. to learn everythign there is to know for F215..

    p.s. anyone know a thread for the F214 exam on 25/06/10 ? please send a link..
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    (Original post by Remarqable M)
    im sure i read somewhere in the book saying a recent research has showing that abscisic acid has nothing to do with abscission of leaves
    6. Abscission

    ABA also promotes abscission of leaves and fruits (in contrast to auxin, which inhibits abscission).


    Found this on http://users.rcn.com/jkimball.ma.ult...ges/A/ABA.html if you want to take a look.

    Seeing as nobody actually knows, I'll probably just go with other functions of it, probably the closure of the stomata in stress.
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    Can someone go through meiosis and meiosis 2 for me.. in like real simple terms. As simple as possible just so I can get my head round it then I can work through textbook on it. I just can't seem to get my head around chromosome numbers and stuff
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    (Original post by Falcon91)
    With reference to bread wheat, you need to know the general idea that it was a wild species that gave rise to a sterile hybrid due to the homologous pairs unable to form during meiosis so couldnt form gametes. Then a mutation doulbed the chromosome number which allowed it to then breed with another species of wheat. Again sterile hybrid, mutation doubled the number of chromosomes and again leading to a hybrid which is hexaploid (6n chromosomes).

    This then means nuclei have to be bigger to store the extra chromosomes, thus cells are bigger.

    The bread wheat species has a characteristic called polyploidy which allosw it to contain more than one set of diploid chromosomes in its nuclei.

    They are then bred to produce more desirable traits, such as resistance to stem bending due to wind and rain, drought, pest and herbicide resistances etc.

    I dont think you need to know the in-depth species names etc of the wheat itself.
    Thank you Was just getting confused between the two books. Trying to do past papers at the moment, but not sure which ones are relevant. Is it the 2804 ones that are similar to this paper?
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    (Original post by Tinkerbelle ♥)
    Can someone go through meiosis and meiosis 2 for me.. in like real simple terms. As simple as possible just so I can get my head round it then I can work through textbook on it. I just can't seem to get my head around chromosome numbers and stuff
    I'm not sure if you've seen these PDFs uploaded by lexafish. They're very clearly presented. Look at F215, pg 3.

    Edit: This website is also pretty useful. Just continue clicking on "Next concept" to go to the next phase.
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    Is pcr and the chain termination method two different things? chain termination involves like the nucleotides being modified and 'throwing off' the polymerase enzyme...do we need to know both?
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    Hey if anyone could answer this it would be a HUGE help!!

    Compare and contrast the action of synapses and neuromuscular junctions

    Can't find it in my textbook or rev guide!
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    For the lac operan do we need to know about its structure, and enzyme induction?
    Or just what happens when lactose is/isn't present?
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    (Original post by zoop)
    Hey if anyone could answer this it would be a HUGE help!!

    Compare and contrast the action of synapses and neuromuscular junctions

    Can't find it in my textbook or rev guide!
    umm normally at neuromuscular joints the neurotransmitter is acetylcholine whereas with neurone to neurone synapses it could e a range of neurotransmitters.
    In neuromuscualr junctions the postsynaptic membrane is the sarcolemma whereas with synapses its the membrane of another neurone.
    At a neuromuscular junction the wave of depolarisation travels deep affecting the t-tubules but with synapses it just depolarises the post synaptic neurone but not to such an extent

    not really sure but thats what I can remember
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    *yawns* thats f212 done...
    aight be back tomorrow
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    (Original post by zoop)
    Hey if anyone could answer this it would be a HUGE help!!

    Compare and contrast the action of synapses and neuromuscular junctions

    Can't find it in my textbook or rev guide!
    From what I can recall:
    In a neuromuscular junction the post synaptic part is the sarcoplasm such that just as in the synapses the post bit gets depolarised after the transmitter substance attaches to the receptors which causes input of NA+ ions into the post-synaptic end same goes here.This depolarization of Sarcoplasmic reticulum causes Ca2+ ions to be released and as we know these ions attach onto the troponin (the ball structure) which was embedded upon the wirey structure (Tropo myosin)
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    (Original post by BHAM!)
    umm normally at neuromuscular joints the neurotransmitter is acetylcholine whereas with neurone to neurone synapses it could e a range of neurotransmitters.
    In neuromuscualr junctions the postsynaptic membrane is the sarcolemma whereas with synapses its the membrane of another neurone.
    At a neuromuscular junction the wave of depolarisation travels deep affecting the t-tubules but with synapses it just depolarises the post synaptic neurone but not to such an extent

    not really sure but thats what I can remember
    [/QUOTE]From what I can recall:
    In a neuromuscular junction the post synaptic part is the sarcoplasm such that just as in the synapses the post bit gets depolarised after the transmitter substance attaches to the receptors which causes input of NA+ ions into the post-synaptic end same goes here.This depolarization of Sarcoplasmic reticulum causes Ca2+ ions to be released and as we know these ions attach onto the troponin (the ball structure) which was embedded upon the wirey structure (Tropo myosin) [/QUOTE]

    Thanks guys, really helps. Also looked at Lexafish's stuff, seriously its amazing would reccommend everyone having a look at it if u have probs with specific points in the syllabus.

    And ibys... what doya mean finished F212? U doing it as a retake or revising it synoptically for this module? I haven't even looked back at AS! EEeeep!
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    From what I can recall:
    In a neuromuscular junction the post synaptic part is the sarcoplasm such that just as in the synapses the post bit gets depolarised after the transmitter substance attaches to the receptors which causes input of NA+ ions into the post-synaptic end same goes here.This depolarization of Sarcoplasmic reticulum causes Ca2+ ions to be released and as we know these ions attach onto the troponin (the ball structure) which was embedded upon the wirey structure (Tropo myosin) [/QUOTE]

    Thanks guys, really helps. Also looked at Lexafish's stuff, seriously its amazing would reccommend everyone having a look at it if u have probs with specific points in the syllabus.

    And ibys... what doya mean finished F212? U doing it as a retake or revising it synoptically for this module? I haven't even looked back at AS! EEeeep![/QUOTE]

    Where are these notes?
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    (Original post by _lynx_)
    I'm not sure if you've seen these PDFs
    Theres the notes by Lexafish.
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    (Original post by zoop)
    Hey if anyone could answer this it would be a HUGE help!!

    Compare and contrast the action of synapses and neuromuscular junctions

    Can't find it in my textbook or rev guide!
    Pg. 270 of the official OCR TB (the one with the brain on) has the answer to this question in the form of a really useful table!
 
 
 
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