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    (Original post by tara592)
    umm yeah I think so...
    so only a few plasmids take up the insulin gene. those that do are no longer resistant to ampicillin because the insulin gene is inserted into the plasmid which deactivates its resistance. But not many plasmids take up the human insulin gene, and even less bacteria take up the plasmids. so you grow the bacteria on standard medium to produce colonies. then grow on tetracycline - any bacteria that have taken up plasmid will survive. then grow on ampicillin - only plasmids that havent taken up insulin gene will grow. so recombinant plasmids will die on ampicillin medium as they dont have the resistance gene. then you compare the 2 to identify transformed bacteria

    is that right?
    Actually the insulin gene is inserted into the tetracycline resistance gene, I dunno if you can reverse it by saying its on the ampicillin resistance gene because i dont think the base sequence is present to provide sticky ends for the insulin gene, :confused: im not sure if its a critical point though anyone else know if im right?
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    (Original post by Chelbobalopolus)
    Actually the insulin gene is inserted into the tetracycline resistance gene, I dunno if you can reverse it by saying its on the ampicillin resistance gene because i dont think the base sequence is present to provide sticky ends for the insulin gene, :confused: im not sure if its a critical point though anyone else know if im right?
    ahh no! it says in my book its ampicillin, they must have printed it wrong! okay hopefully Ill remember to put it the other way round now, but hopefully they wont be too mean :P

    Ive been reading a lot of the AS work today, but not the specific details...they wouldnt expect us to remember all the details (like how the heart contracts, differences between B and T lymphocytes etc) would they? Ive just been reading it to jog my memory, but dont know if thats enough...actually cant wait for this week to be over!!
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    (Original post by tara592)
    ahh no! it says in my book its ampicillin, they must have printed it wrong! okay hopefully Ill remember to put it the other way round now, but hopefully they wont be too mean :P

    Ive been reading a lot of the AS work today, but not the specific details...they wouldnt expect us to remember all the details (like how the heart contracts, differences between B and T lymphocytes etc) would they? Ive just been reading it to jog my memory, but dont know if thats enough...actually cant wait for this week to be over!!

    my book says tetracycline *sigh* ocr, i havnt actually had the chance to look over AS ive been making links between this and the january module, deffinatly insulin seems to play a big part and diabetes so id learn them, osmoregulation and the hypothalmus seems like something that could turn up. Im not sure though only guessing
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    What do we have to know about homeobox genes?
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    (Original post by Chelbobalopolus)
    my book says tetracycline *sigh* ocr, i havnt actually had the chance to look over AS ive been making links between this and the january module, deffinatly insulin seems to play a big part and diabetes so id learn them, osmoregulation and the hypothalmus seems like something that could turn up. Im not sure though only guessing
    My book says tetracyline too and that's what I've been learning but look at this from wiki:

    "Bacterial DNA often has two resistancy genes: one for tetracycline and one for ampicillin. The insulin gene can be inserted in the middle of the ampicillin gene after it has been removed using restriction endonucleases. If the gene has been taken up, the bacteria both produces insulin and is also no longer ampicillin resistant. "

    Darn textbook!!!
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    I kinda have a question it may sound silly but im not from a maths background. So the hardy weinberg principle where p(2) = the frequency of homozygous dominant genotype, q(2) = the frequency of the homozygous recessive genotype and 2pq= the heterozygous genotype. Would you ever be given at the start of a question the number of people in a population that have the heterozygous genotype say 2/2000 have Ff, i just wouldnt know where to start with breaking down 2pq. lol that sounds confusing
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    (Original post by InvoluntarySlacker)
    What do we have to know about homeobox genes?
    not too sure but all i know is that the body plan is a structure of an organism. and proteins control the development. they're found in animals and plants too.
    Homeotic gene contains sequences called homeobox sequences, these sequences code for the protein homeodomain.
    the homeodoman acts as like a transcription factor (a similar method to the repressor protein in lac operon), it binds at the start of developmental genes and activates ore represses them.

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    what is everybody here talking about with the ampicillin and tetracycline resistance and deactivation? i know that these are both antibiotics, but the way we were taught it was to simply add the tetracycline or ampicillin resistance gene into the plasmid along with the desired (eg. insulin) gene and just use that as a marker.

    so...?
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    Quick question: could someone summarise the golden rice please? There seem to be mixed messages about the enzymes needed etc and how many.... In the heinemann textbook it just says one gene from daffodils coding for phyotene synthetase but some people are saying two genes are taken from daffodils? And the gene from erwina uredovora, is it Crt-1 or carotene desaturase coz I've heard both names used?? Also, is it agrobacterium used to get the genes into the rice plant?
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    Does anyone have any exam questions for module 4 ?

    If not which biology papers cover all the stuff in module 4?

    Cheers guys
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    For synoptic questions: OCR are kind enough to show us what we need to learn for questions from past modules in the specification. :mmm:

    F211 Module 1, 2, 3
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    I mean F211: Module 1 and F212: 1, 2 and 3
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    i dont have my notes from last year ; _ ; can someone help in anyway ?
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    (Original post by AnniG)
    My book says tetracyline too and that's what I've been learning but look at this from wiki:

    "Bacterial DNA often has two resistancy genes: one for tetracycline and one for ampicillin. The insulin gene can be inserted in the middle of the ampicillin gene after it has been removed using restriction endonucleases. If the gene has been taken up, the bacteria both produces insulin and is also no longer ampicillin resistant. "

    Darn textbook!!!
    oh okay then, so they shouldnt penalise any marks if we put them the other way round, as long as all the key words are there!

    just trying to think of other hefty questions they could ask us for synoptic...plant adaptations: theres all the stuff about them being xerophytic to reduce water loss, xylem and phloem vessels,all the features of a plant cell and then the features of the chloroplast, light dependant/independant stage, limiting factors (temp (enzymes/stomata), CO2 conc (stomata) and light intensity (wavelength) all from the previous modules. and then for this unit there's all the hormones and tropisms.

    URGH!!


    ohh and btw can someone explain all the methods for preserving/conserving an ecosystem? I get confused between the 2, all I seem to remember is coppicing :/
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    (Original post by AnniG)
    Quick question: could someone summarise the golden rice please? There seem to be mixed messages about the enzymes needed etc and how many.... In the heinemann textbook it just says one gene from daffodils coding for phyotene synthetase but some people are saying two genes are taken from daffodils? And the gene from erwina uredovora, is it Crt-1 or carotene desaturase coz I've heard both names used?? Also, is it agrobacterium used to get the genes into the rice plant?
    GOLDEN RICE

    • Vitamin A - forms visual pigment (eyesight), involved in glycoprotein synthesis, maintenance of epithelial cells, and bone growth.
    • Beta-carotene is precursor to vitamin A (retinol), and is eaten when meat isn't available. It's called pro-vitamin A
    • Most enzymes for metabolic pathway for beta-carotene production already present in endosperm. Only 2 genes need to be inserted to activate the metabolic pathway.
    • the genes are psy (Daffodil) and crt1 (soil bacterium)
    • These genes are inserted into a Ti plasmid, forming a recombinant plasmid.
    • The plasmid is taken up by agrobacterium tumefaciens, (transformed bacteria)
    • A. tumefaciens infects rice plant genome with the 2 genes; inserted near specific promoter sequence associated with endosperm development.
    • Gene is transcribed and translated in the endosperm - which produces a protein that synthesises beta-carotene, giving the endosperm a yellow/orange colour, hence golden rice. It is bio fortified (higher conc. of particular nutrient than normal)
    • A marker gene may also be used, so the rice cells only grow on a selective medium.




    name 2 proteins found in the I band - actin and....???:confused:
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    (Original post by mikey_g)
    GOLDEN RICE

    • Vitamin A - forms visual pigment (eyesight), involved in glycoprotein synthesis, maintenance of epithelial cells, and bone growth.
    • Beta-carotene is precursor to vitamin A (retinol), and is eaten when meat isn't available. It's called pro-vitamin A
    • Most enzymes for metabolic pathway for beta-carotene production already present in endosperm. Only 2 genes need to be inserted to activate the metabolic pathway.
    • the genes are psy (Daffodil) and crt1 (soil bacterium)
    • These genes are inserted into a Ti plasmid, forming a recombinant plasmid.
    • The plasmid is taken up by agrobacterium tumefaciens, (transformed bacteria)
    • A. tumefaciens infects rice plant genome with the 2 genes; inserted near specific promoter sequence associated with endosperm development.
    • Gene is transcribed and translated in the endosperm - which produces a protein that synthesises beta-carotene, giving the endosperm a yellow/orange colour, hence golden rice. It is bio fortified (higher conc. of particular nutrient than normal)
    • A marker gene may also be used, so the rice cells only grow on a selective medium.




    name 2 proteins found in the I band - actin and....???:confused:
    troponin or tropomyosin.
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    synoptic will be imbedded in to questions, i wont be obvious. My teacher went to an OCR conference and they said the question will be linked to synoptic and it wont necessarily be obvious.
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    (Original post by skatealexia)
    troponin
    thankss

    in your spoiler, OCR Biology Unit 4- 25th June, thats not f215 your talking about right?cause its the 16thh
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    ... its the resit from jan,I just call it unit 4 :L
 
 
 
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