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    how would you answer this.... outline how genetic markers in plasmid can be used to identify the bacteria that have taken up a recombinant DNA...i know its prob sumthing related to replica plating..jus no clue how to answer it
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    (Original post by lmfw)
    Use pastpapers.org, the paperbank is doggy for ads and virus'
    thankyouuuu :adore: will rep when I have any haha hmmm, it will let me rep others and not you... must have given some to you recently haha x
    (Original post by aquarius00)
    how would you answer this....'outline how genetic markers in plasmid can be used to identify the bacteria that have taken up a recombinant DNA'...i know its prob sumthing related to replica plating..jus no clue how to answer it
    - genetic markers in E.Coli are the genes coding for resistance to 1) ampicillin and 2) tetracycline
    - the restriction markers target on the 'restriction site' that is located right in the middle of the code for tetracycline
    - when the insulin gene/or any gene for that matter is inserted into the plasmid, it is in this location
    - means the bacteria has no resistance to tetracycline anymore

    therefore we know that any bacteria that grows on ampicillin but not one tetracycline has successful taken up a plasmid containing the gene!
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    (Original post by Mally-xo)
    urm that kinda just took me to some random comparison site, and when I tried 'thepaperbank', which I am guessing you meant, it flagged up as a potential threat on my antivirus. so thanks... btw I didn't neg you lol
    the same happened to me
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    Sorry if this has already been asked but has anybody analysed recent papers to have an idea on what is likely to come up tomorrow? I hope not much comes on about gene technology
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    Can I just say this revision has been made a whole lot more bearable due to you guys and gals, and any grade I get is probably down to the time I spent on here (much to the disbelief of my parents :rofl:)
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    (Original post by Mally-xo)
    urm that kinda just took me to some random comparison site, and when I tried 'thepaperbank', which I am guessing you meant, it flagged up as a potential threat on my antivirus. so thanks... btw I didn't neg you lol
    Yaa i meant that! sorry! Eughhh, I seem to get negged by people for trying to help haha

    I use FireFox with adblock plus and it neutralises thepaperbank. But in all honesty, the amount of papers i printed off to find 1 question relevant to the specification was ridiculous :|

    Need more F215 papers
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    (Original post by Srikmeister)
    Sorry if this has already been asked but has anybody analysed recent papers to have an idea on what is likely to come up tomorrow? I hope not much comes on about gene technology
    meiosis hasn't come up as a big question yet and i don't think there's really been anything on it in terms of little questions either so potentially an essay question on that i think, and maybe on the lac operon too. possibly sliding filament but who knows!

    i've been revising for months for this exam, sat down to do a past paper earlier and just forgot EVERYTHING. so much is riding on this exam! :cry:
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    any idea what the answer to this is... 'describe the genetic difference between sister and non-sister chromatids'
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    (Original post by Kidms001)
    Can I just say this revision has been made a whole lot more bearable due to you guys and gals, and any grade I get is probably down to the time I spent on here (much to the disbelief of my parents :rofl:)
    .

    :h:
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    what is a clade and what is cladistic?
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    (Original post by kwindsor)
    meiosis hasn't come up as a big question yet and i don't think there's really been anything on it in terms of little questions either so potentially an essay question on that i think, and maybe on the lac operon too. possibly sliding filament but who knows!

    i've been revising for months for this exam, sat down to do a past paper earlier and just forgot EVERYTHING. so much is riding on this exam! :cry:
    Thanks. That has happened quite a lot this year to me haha! Best of luck to you! I hope everything goes well
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    (Original post by Mally-xo)
    any idea what the answer to this is... 'describe the genetic difference between sister and non-sister chromatids'
    Sister chromatids have the same genetic material.
    Non sister chromosomes have different genetic material, like when two bivalents join by the chiasmata in meiosis (prophase I), the two joined together are non sister
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    (Original post by Luke0011)
    Sister chromatids have the same genetic material.
    Non sister chromosomes have different genetic material, like when two bivalents join by the chiasmata in meiosis (prophase I), the two joined together are non sister
    muchas gracias senor xxx
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    (Original post by Mally-xo)
    muchas gracias senor xxx
    I had JUST gone over it
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    (Original post by Mally-xo)
    any idea what the answer to this is... 'describe the genetic difference between sister and non-sister chromatids'

    (Original post by Luke0011)
    Sister chromatids have the same genetic material.
    Non sister chromosomes have different genetic material, like when two bivalents join by the chiasmata in meiosis (prophase I), the two joined together are non sister
    My teacher says that it is safer to say they contain the same alleles or nucleotide base sequence :holmes: .. Genetic material is a bit ambiguous apparently :dontknow:
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    If there's a question about the sliding filament model would you just talk about the power stroke or would you start from an action potential arriving at a neuromuscular junction?
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    (Original post by Kidms001)
    My teacher says that it is safer to say they contain the same alleles or nucleotide base sequence :holmes: .. Genetic material is a bit ambiguous apparently :dontknow:
    Ah okay, sounds better! Thanks
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    I WAS CONFIDENT FOR DAYS ND THEN REALISIED THAT EVEN IF I DO WELL IN THIS EXAM OR DO OK ... I STILL HAVENT STARTED MY REVISION FOR UNIT 4! i did it in jan and got a High C and all my teachers were saying 2 me 2 get it remarked but i didnt... my friend got the exact same grade and got it remarked and got a A only he told me after the deadline had passed! wish i attempted tht remark! getting an A/A* in bio is freaking annoying work!
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    (Original post by Wor Carroll)
    If there's a question about the sliding filament model would you just talk about the power stroke or would you start from an action potential arriving at a neuromuscular junction?
    this is how I would answer it:
    - impulse arrives at the neuromuscular junction (don't ramble TOO much about this) and releases the neurotransmitter, which binds to receptors on the
    muscle membrane, causing depolarisation down the T tubules
    - this stimulates the release of Calcium 2+ ions from the sarcoplasmic reticulum
    - the Ca ions bind to troponin, which means the tropomyosin shape changes and allows the binding of the myosin filament's head
    - the power stroke occurs where ATP (supplied by aerobic/anaerobic respiration and creatine phosphate transfer) breaks the cross-bridge formed between actin and myosin
    - can then reform further along causing contractions
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    (Original post by Wor Carroll)
    If there's a question about the sliding filament model would you just talk about the power stroke or would you start from an action potential arriving at a neuromuscular junction?
    unless they state 'what happens in the sarcomere' i would start by explaining what happens at the neuromuscular junction with the depolarisation and the calcium ions.
    you may get an extra mark.
 
 
 
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