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AQA BIOL5 Biology Unit 5 Exam - 22nd June 2011 watch

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    hey, why doesnt insulin take part in the second messenger model?
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    (Original post by Stirlo)
    The A band consists of the entire area where myosin filaments are present not just actin and myosin. WHich is why upon contraction the A band width stays the same as the myosin filaments don't contract. You're right with the other 2 though


    thanks a lot
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    (Original post by Tericon)
    Yes

    Two others:

    M-line = middle of H zone, so just myosin

    Z-line = marks boundaries of sarcomere

    I remember AIH

    A bands stay same length during contraction, I bands get shorter, H zone gets shorter. As does sarcomere.
    thanks
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    (Original post by Tericon)
    Thanks, that sounds like a potential nasty question, didn't know that, CGP just says A = actin and myosin.
    The CGP definition is badly worded tbh, but it does actually say what I said (I learnt it from there xD) just takes a couple times to actually see it.

    "Dark (A bands) bands contain the thick myosin filaments and some overlapping thin actin filaments"

    Just badly worded
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    (Original post by angel1992)
    hey, why doesnt insulin take part in the second messenger model?
    Insulin, Adrenaline and Glycagon all work using the 2nd messenger model
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    (Original post by Nadine2010)
    Why is atpase required in muscles? If it for the myosin head to return to it's original position andd to detach the cross bridges or is 'atp' used for that as an energy source?!?!?!
    ATP is hydrolised to form ATP and Pi, this causes a "power stroke", then ATP is needed again which binds to mysosin head, then detaches from the mysoin head, ATP is then hydrolysed, which re-engerizes the mysoin head.
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    Can somebody please be kind enough to summarise the process of genetic fingerprinting. :p:
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    (Original post by angel1992)
    hey, why doesnt insulin take part in the second messenger model?
    all hormones do, that is how they work
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    (Original post by Carpet21)
    The book doesn't really tell us much about troponin does it?
    Troponin is just a protein thats attached to tropmyosin.
    Ca2+ ions attach to troponin, which moves tropomyosin and the actin binding sites are exposed.
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    (Original post by addvic)
    all hormones do, that is how they work
    really so why does it say on glucagon and adrenaline do in all the books, it doesnt say insulin doing this>?
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    (Original post by angel1992)
    really so why does it say on glucagon and adrenaline do in all the books, it doesnt say insulin doing this>?
    Because the example given by the books involves the liver cells. only glucagon and adrenaline stimulate liver cells to release glucose, not insulin.
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    (Original post by angel1992)
    really so why does it say on glucagon and adrenaline do in all the books, it doesnt say insulin doing this>?
    Dependent on whether they are hydrophobic ((Oestrogen)= Lipid) or hydrophillic ((Insulin, Adrenaline, Glycagon) =Non-lipid)
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    (Original post by Master.K)
    Can somebody please be kind enough to summarise the process of genetic fingerprinting. :p:
    DNA contains repetitive sequences of bases which don't code for any protein (the introns i think). These codes are pretty much specific to each individual however they are inherited from the parents, a close to even amount from each however which sequences are random. In fingerprinting you can compare these regions of DNA from two or more individuals. So in finding say a father you could get a sample of both the mother and suspected father and compare it your own. All of the fragments of your introns should pair up with one of your parents if they are both your parents.

    At crime scenes they'll use the DNA evidence there and cross check it with the suspects.

    Sorry hope that helped
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    (Original post by Master.K)
    Can somebody please be kind enough to summarise the process of genetic fingerprinting. :p:
    • Uses non-coding repeated sequences in DNA, these are different lengths in different people.
    • These fragments are isolated, then PCR is used to obtain substantial amount.
    • All the DNA fragments are marked in some way (eg fluorescence).
    • DNA fragments undergo electrophoresis, placed in a conductive gel, and an electrical current flows through the gel. Seen as DNA is negatively charged, they flow towards the positive electrode at end of gel.
    • The distance travelled through gel is related to size of fragments, smaller fragments will travel further.
    • These lengths can then be compared between different people.
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    Hi, I have a couple of questions, firstly,
    say you wanted to insert a gene like the gene for healthy CFPR channel protein, you spray you insert it into harmless adenovirus etc and spray into nostrils, however, they say it would be more effective if the could get it to stem cells, which would provide a more long-term solution, but how? Once stem cells have divided, they're not replaced with new stem cells, so does the treatment have to be repeated for the stem cells? I'm a bit confused with this...can anyone help?
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    (Original post by NRican)
    So in the NT book page 268 (last paragraph) the DNA strand would be AT, GC, CG and so on?
    The bands would be (Primer)+A
    - (Primer)+AG
    - (Primer)+AGC
    -(Primer)+AGCT

    and so on.

    Therefore the sequence would be AGCTTGAC (just take the last base in each band)



    Therefore the sequence on your original DNA sample must be TCGAACTG
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    Jeez is June 2010 the only BIOL5 past paper out there? I need to do a mock test before tomorrow!
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    Can anyone explain replica plating please thank you?
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    ohh so how does insulin act as a second messenger??? what is an example?
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    Who else feels like they're going to get anally raped in this exam?
 
 
 
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