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

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    just finished revising all of unit 5 today since like 2 months ago. now im like 'oh yeah... the essay...'
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    (Original post by sarahlovesleon)
    just finished revising all of unit 5 today since like 2 months ago. now im like 'oh yeah... the essay...'
    youve been revising for 2 months?!?!?!?! :eek::eek::eek::eek::eek::eek::eek:
    that makes me feel like ive done no revision!! aha
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    GENETIC FINGERPRINTING
    ? The genome of an organism contains many repetitive non-coding regions.
    ? The statistical chances of two people carrying the same regions are very low.
    ? The process follows five main processes.

    1. Extraction; DNA is extracted from cells and amplified using PCR.
    GENE CLONING TECHNOLOGIES ALLOW STUDY AND ALTERATION OF GENE
    FUNCTION IN ORDER TO BETTER UNDERSTAND ORGANISM FUNCTION ...
    2. Digestion; Restriction endonuclease enzymes are selected to cut up the DNA into fragments.
    3. Separation: The fragments are separated according to size by gel electrophoresis. The gel is made alkaline to separate the double strands. The single-strands are then transferred to a nylon membrane by Southern blotting (nylon membrane is laid over the gel ... covered with sheets of absorbent paper to draw up the liquid with the DNA which transfers it to the membrane ... Fragments are then fixed with UV light).
    4. Hybridisation: labelled DNA probes then bid o the core sequences. Many different probes are used to ensure all the fragments are recognised.
    5. Development: A photographic sheet is then placed over the sheet and the x-rays emitted by the radioactive probes develop the film and generate bands corresponding to the positions of the DNA fragments.

    Uses of genetic fingerprinting
    ? Forensic science to determine the extent to which an individual is connected to a crime.
    ? Paternity testing (Jeremy Kyle show!)
    ? Genetic variability assessments for conservation purposes.
    ? Selection of breeding pairs for endangered species to ensure the mates are not familiarly related.
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    Can someone please help me with the last two questions on the specimen paper? q10c i and ii?

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

    I know the answers, but don't understand how on earth you can work them out from the graph? Also, what on earth is the heat-killed wild type?
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    (Original post by emmaaa65)
    youve been revising for 2 months?!?!?!?! :eek::eek::eek::eek::eek::eek::eek:
    that makes me feel like ive done no revision!! aha
    yeah started in April half term! but obviously over the last 2 weeks i've been doing less biology because I had all my other exams.

    Anyone doing the essay first?
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    Plasmids contain the bacteria’s genes for antibiotic resistance.
    ? If a restriction enzyme is used which cuts across this gene and a DNA fragment is
    inserted, it follows that the bacteria will no longer be resistant to that antibiotic.
    ? This can be used to identify the bacterial cells that have taken up the target gene.

    1. After transformation, the cells are plated onto a sterile plate containing a
    nutrient agar containing ampicillin and incubated for about 24 hours.
    2. Only those cells which took up plasmids will be resistant to ampicillin and
    survive to grow on as colonies.
    3. A replica plate is made using a velvet cloth and the cells are transferred to a plate containing tetracycline (the antibiotic for which the target gene was inserted across its resistance gene).
    4. Following incubation some colonies remain resistant and some die.
    5. Those colonies which died on the second plate must therefore contain the correctly transformed bacteria which can express the target gene.
    6. These colonies can then be identified on the first plate and then samples removed and cloned in a fermenter
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    (Original post by moniquesungirl)
    Anyone fancies to do a recap of chapter 16? For me is the hardest one :/
    i find synapses and action potentials harder!
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    haha jin, the pikachu in your sig is so distracting! (and cute)
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    Not a lot of practice papers for this exam in fact there is only the one I think which is June 2010. Has anyone else got any links to other papers except the specimen one. Can you please quote me the Jan 2011 paper if you have it. Thanks

    P.S. - Also links to grade boundaries will also be appreciated.
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    how is the PCR used in making probes?
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    (Original post by Boo!xx)
    haha jin, the pikachu in your sig is so distracting! (and cute)
    Haha
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    sorri guys but i do not understand why they use the sanger method and how that helps locate the bases they are lookin got, i mean if they didnt kno the bases they lookin for so then why are primers complemantary to it

    many thanks!!!! :P
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    Think im gonna call it a day for revision now... im EXHAUSTED.

    Ill get up at 6am and revise for a bit in the morning. But i feel like ive took in enough my brain can handle tonight. Think ill just be better off getting some SLEEP.
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    (Original post by mkb230)
    Not a lot of practice papers for this exam in fact there is only the one I think which is June 2010. Has anyone else got any links to other papers except the specimen one. Can you please quote me the Jan 2011 paper if you have it. Thanks

    P.S. - Also links to grade boundaries will also be appreciated.
    There is no Jan 2011 paper, only June 2010 and specimen
    grade boundaries for last June are:

    http://store.aqa.org.uk/over/stat_pd...UND-JUNE10.PDF
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    (Original post by appleschnapps)
    http://www.thestudentroom.co.uk/show...369&highlight=

    Er, hopefully simply enough?
    Your diagram is fantastic, but I'm still a little confused...

    I get that 2 must be nearest the label as its the radioactive fragment, but its the partial digests that confuse me, they add up to more than 10? How can this be?

    How to find the fragment nearest the radioactive label is pretty much the only bit of RM i get
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    (Original post by mkb230)
    Not a lot of practice papers for this exam in fact there is only the one I think which is June 2010. Has anyone else got any links to other papers except the specimen one. Can you please quote me the Jan 2011 paper if you have it. Thanks

    P.S. - Also links to grade boundaries will also be appreciated.
    Unit 5 can't be taken in January so the only papers are the specimen and June 2010. June 2010 grade boundaries:

    A* 69
    A 62
    B 55
    C 49
    D 43
    E 37
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    (Original post by emmaaa65)
    youve been revising for 2 months?!?!?!?! :eek::eek::eek::eek::eek::eek::eek:
    that makes me feel like ive done no revision!! aha
    Don't worry, two days. :five:
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    (Original post by percy93)
    how is the PCR used in making probes?
    The bases on the mutated gene are determines by DNA sequencing and stored in genetic libraries.
    A fragment of DNA that has bases complementary to the mutated portion of the gene is produced.
    The DNA fragment is radioactively labelled to produce a DNA probe (or the nucleotides are radioactively labelled to be more accurate)
    And PCR is used to produce many compies of this DNA probe using radioactive nuclotides rather than normal ones.
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    (Original post by Abby :))
    Think im gonna call it a day for revision now... im EXHAUSTED.

    Ill get up at 6am and revise for a bit in the morning. But i feel like ive took in enough my brain can handle tonight. Think ill just be better off getting some SLEEP.
    Good niiiight and good luck tomorrow!
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    got a really strong feeling the essay will be something about ecology and i've learnt no ecology. i hope to god its proteins or cells or something
 
 
 
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