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    Differences:

    Synapses: Neurone to neurone, smooth, and round synaptic knob, post synaptic stimulation leads to an action potential in the post synaptic neurone.
    Neuromuscular: Neurone to Sarcomere, motor end plate with 'brush like' microvilli ( I think), flattened up to muscle fibre. Postsynaptic stimulation leads to the depolorisation of the Sarcolemma and eventually muscle contraction.

    Similarities: Both contain vesicles which contain neurotransmitter, both release neurotransmitter into the synaptic cleft, in both this diffuses across the synaptic cleft and binds to a specific receptor on the post-synaptic membrane, and in both neurotransmitter acetylcholine is broken down by acetylcholinesterase at the receptors on the post synaptic membrane to stop the response from continually happening.
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    (Original post by aimz08)
    Also are punnets squares accepted instead of genetic diagrams?
    So for codominance, sex linkage just use parents genotypes? e.g. NN and nn split these to find gametes so N, N, n, n and cross them in a punnet square?
    I use punnet squares if that helps .
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    Do anybody have the specimen paper for this exam........don't think there is a past paper, just need a paper in hand to test myself.........
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    (Original post by Remarqable M)
    what are the differences and similarities between synapses and neuromusclar junctions?
    synapses are neurone to neurone wheras in neuromuscular junctions it is neurone to the sarcomere, In synapses the stimulation leads to an action potential being released wheras in neuromuscular junctions it leads to depolarisation of the sarcolemma which leads to the muscle being contracted.

    Some similarities are such as Neurotransmitters both being located in vesicles in presynaptic membrane, Vesicles both releasing the neurotransmitter into the synaptic cleft, the neurotransmitter diffusing along the synaptic cleft and binding onto the post synaptic receptor and there is also an ezyme preset in both the synapse and neuromuscular junctions which degrades the neurotransmitter to stop a continuous response occuring

    I think thats about it :P
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    (Original post by aimz08)
    Thanks

    Could someone just check I've got the hang of control of protein synthesis please?

    Protein synthesis can be controlled at the genetic level by altering the rate of transcription of genes. (e.g. increase T.R=more mRNA=More protein)
    Protein production in prokaryotes especially bacteria involves operons.
    Operons consist of:
    Structural Gene- code for useful proteins e.g. enzymes
    Control Elements- promoter; DNA sequence before structural gene, RNA polymerase binds to promoter. Operator; Transcription factors bind to this.
    Regulatory Gene- codes for a transcription factor which is a protein that can switch genes on and off by increasing or decreasing rate of transcription. Activators; increase TR and Repressors decrease it.

    Shape of a transcription factor determines whether it can bind to DNA or not; and it's shape may be affected by other molecules such as hormones and sugars.

    One such specific example is the lac operon: E.coli usually respires glucose, however it can also respire lactose when glucose is not present.

    Lactose not present: Repressor protein is synthesised; has two binding sites, one site binds to the operator site, covering part of the promoter region where RNA polymerase usually binds. Hence the RNA polymerase can't bind to the promoter so structural genes can't be transcribed into mRNA, hence genes can't be translated and enzymes can't be synthesised.

    When lactose is present; lactose binds to the other binding site on the repressor protein, changing the shape of the site that binds to operator region so now it can't bind to the operator region, leaving promoter site empty so RNA polymerase can bind to it so transcription of structural gene can begin
    B1: Operons arent limited to prokaryotes. Theyre also found in eukaroytic cells.

    B2: Ive only read about transcription factors in relation to homeobox genes and body plans, so not sure why you've mentioned that here, maybe you're getting the two topics confused? Anyway, the main point about the regulator gene is that it codes for a repressor protein which binds to the operator gene stopping RNA polymerase from transcribing DNA.

    The rest is all okay.
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    (Original post by DR_X)
    Do anybody have the specimen paper for this exam........don't think there is a past paper, just need a paper in hand to test myself.........
    yeah, would be good if someone could post it
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    Could someone offer up a brief explanation of Epistasis? Preferably with an example.
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    (Original post by -F-)
    B1: Operons arent limited to prokaryotes. Theyre also found in eukaroytic cells.

    B2: Ive only read about transcription factors in relation to homeobox genes and body plans, so not sure why you've mentioned that here, maybe you're getting the two topics confused? Anyway, the main point about the regulator gene is that it codes for a repressor protein which binds to the operator gene stopping RNA polymerase from transcribing DNA.

    The rest is all okay.
    B2- I have been using the CGP revision guide and it explains this awfully, thanks that helps me with understanding this a lot better I might just ignore that part...
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    Hey, new to TSR. Hope everyones exams go well!

    Heres the specimen paper for f215

    The mark scheme is at the end of the paper
    Attached Images
  1. File Type: pdf OCR Specimen Paper F215.pdf (730.1 KB, 1671 views)
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    (Original post by aimz08)
    B2- I have been using the CGP revision guide and it explains this awfully, thanks that helps me with understanding this a lot better I might just ignore that part...
    Do you have the OCR textbook? I think lac operons are explained very well in this one:

    http://www.amazon.co.uk/OCR-Biology-...6346922&sr=8-2

    Wish I got this one earlier in the year, it cuts out loadsa waffle, I was using the Mary Jones one until about april.
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    (Original post by Just-Some-Guy)
    Hey, new to TSR. Hope everyones exams go well!

    Heres the specimen paper for f215

    The mark scheme is at the end of the paper
    thanks man!
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    (Original post by -F-)
    thanks man!
    No problem
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    Everything you need e.g. specimen and specification are in the opening post
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    (Original post by skatealexia)
    Differences:

    Synapses: Neurone to neurone, smooth, and round synaptic knob, post synaptic stimulation leads to an action potential in the post synaptic neurone.
    Neuromuscular: Neurone to Sarcomere, motor end plate with 'brush like' microvilli ( I think), flattened up to muscle fibre. Postsynaptic stimulation leads to the depolorisation of the Sarcolemma and eventually muscle contraction.

    Similarities: Both contain vesicles which contain neurotransmitter, both release neurotransmitter into the synaptic cleft, in both this diffuses across the synaptic cleft and binds to a specific receptor on the post-synaptic membrane, and in both neurotransmitter acetylcholine is broken down by acetylcholinesterase at the receptors on the post synaptic membrane to stop the response from continually happening.

    Don't forget that synapses can be inhibitory / excitatory, whilst NMJ are only excitatory! NMJ only uses Acetylcholine (and thus acetylcholinesterase) , synapses may use various neurotransmitters such as Ach or noradrenaline etc (which will require a diffferent respective enzyme to break it down)

    i just want this exam to be overrrrrr!
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    (Original post by Falcon91)
    Reading through my old AS revision guide and reading chucks/lexafish's notes. I dunno if everyone has learnt it off by heart (F211/F212), but i seem to remember a fair bit, just needs refreshing.



    I have the same issue, seems a few others are in the same boat as us too. High marks AS, less good in january. I think when you come to these questions, you have to remember, its not about what you know purely...you have to try and link your knowledge together and understand what its asking of you and come to a reasonable conclusion, you could have worked the seal question from AS knowledge, that CO2 is transported as carbonic acid, and thought the acid could have a buffer so it can be transported, but under pressure many of us didnt remember this i guess. + Agree with chem, at least they say what synoptic stuff they can ask and they build on the concepts, whereas bio it tells you to learn specific points separately (most of the time :P).
    do you know approximately how much of the exam is going to be synoptic :confused: Just that I remember the basics and have read over my revision guide, however I'm wondering whether they're actually going to have a question based entirely on a topic from the other units
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    everyone seems to be really panicking about the synoptic elements..
    the specification says:

    A2 Unit F214: Communication, Homeostasis and Energy
    Candidates answer all questions.
    15% of the total Advanced GCE marks 1 h written paper 60 marks
    This unit contains some synoptic assessment and Stretch and Challenge questions.

    A2 Unit F215: Control, Genomes and Environment
    Candidates answer all questions.
    25% of the total Advanced GCE marks 1 h 45 min written paper 100 marks
    This unit contains some synoptic assessment and Stretch and Challenge questions.

    ^^directly quoted
    this means unit f214 in jan was also synoptic so i assume we can expect the same level/amount of synoptic questions
    (which in january didnt seem to be very much at all)

    so lets all chill out a bit :P
    and focus on f215 spec - where MOST of the marks will be
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    My teacher said they can only ask a maximum of 12 marks on the synoptic stuff. And she's a marker for OCR, so I assume she's correct

    Anyway, how's everyone doing with the plant hormones stuff? I'm having real trouble remembering all the little processes you need to know, like expansins and leaf senescence... it's just so boring! I try to remember it all but I don't feel interested enough

    Everything else isn't too bad though, just seems to be LOADS of remembering to do.
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    (Original post by -F-)
    B2: Ive only read about transcription factors in relation to homeobox genes and body plans, so not sure why you've mentioned that here, maybe you're getting the two topics confused? Anyway, the main point about the regulator gene is that it codes for a repressor protein which binds to the operator gene stopping RNA polymerase from transcribing DNA.
    Transcription factors are proteins that bind to DNA to either facilitate the binding of RNA polymerase, or to inhibit its binding. So i think it's far clearer to refer to this particular transcription factor as a repressor protein, as there will be plenty of other transcription factors involved which allow RNA polymerase to bind at all!
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    my teacher said that synoptic questions are inbedded in question that you wont realise.

    for example, when you talk about maintaining conditions in fermenter you talk about enzyme activity which people talk about naturally, That is like synoptic.
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    (Original post by TX22)
    my teacher said that synoptic questions are inbedded in question that you wont realise.

    for example, when you talk about maintaining conditions in fermenter you talk about enzyme activity which people talk about naturally, That is like synoptic.
    YES :yep:
    agreed big time
    you talk denaturing and stuff which is synoptic
    i hope this is the whole synoptic element lol :p:
 
 
 
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