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    (Original post by Sakujo)
    I think you got that the wrong way round, it should be Yes for replication and No for transcription.
    youve got the wrong idea *Archen, it says NO for DNA rep, yes for transcription.

    I had a mass debate with my teacher about this question, he said in the end the question wasnt clear enough in making the distinction.

    the question says tick where its necessary - the question is the original DNA strand is unchanged by the process.

    NO for DNA rep - It can be argued that it is changed, as the strands produced are newer in replication so each double helix is made from an old and new strand, and thus the answer is YES it is CHANGED, so the answer is a CROSS.

    YES for transcription - because the strand has NOT been changed, just transcribed onto an mRNA. so the answer is TICK.

    Youve misinterpreted i think.
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    (Original post by Archen)
    well the mark scheme says otherwise :ninja:

    so VERY confused
    Sorry I thought it said changed, it says unchanged.:o:

    In that case it is correct. Semi-conservative replication occurs so that original double DNA strand that you had has split and formed two new double strands. Transcription only unwinds the gene needed to be transcribes, it is sealed back together by an enzyme whose name I should know. :hmmmm:
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    (Original post by Falcon91)
    youve got the wrong idea sakujo, it says NO for DNA rep, yes for transcription.

    I had a mass debate with my teacher about this question, he said in the end the question wasnt clear enough in making the distinction.

    the question says tick where its necessary - the question is the original DNA strand is unchanged by the process.

    It can be argued that it is changed, as the strands produced are newer in replication so each double helix is made from an old and new strand, and thus the answer is YES it is CHANGED, so the answer is a CROSS.

    YES for transcription - because the strand has NOT been changed, just transcribed onto an mRNA. so the answer is TICK.

    Youve misinterpreted i think.
    Yes I have see other post.
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    Just getting started on muscle contraction malarky c3 tomorrow aswell
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    (Original post by Sakujo)
    Sorry I thought it said changed, it says unchanged.:o:

    In that case it is correct. Semi-conservative replication occurs so that original double DNA strand that you had has split and formed two new double strands. Transcription only unwinds the gene needed to be transcribes, it is sealed back together by an enzyme whose name I should know. :hmmmm:
    It's not ligase is it? :confused: I really need to look over this topic.
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    (Original post by _lynx_)
    It's not ligase is it? :confused: I really need to look over this topic.

    In transcription only the hydrogen bonds are broken, the sugar-phosphate backbone remains intact. I think the hydrogen bonds form back together without the need for an enzyme, so don't worry!
    DNA ligase is used to reform the sugar phosphate backbone when you're cutting plasmids / genes etc
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    Blergghh!

    I have 3 pages to go for Mod 1 which Ive given up on.
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    (Original post by -F-)
    yes me! im still trying to learn the spec, forget reivsing. some of this stuff is new to me. and im meant to be getting a B :o:
    lol same here..supposed to get a B and I'm learning new stuff!

    Glad I'm not alone in revising til the early hours but still will try to pop into this thread to keep me sane!
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    lynx i tink we only need to know the enzyme involved in unwindin n unzziping of dna double strand which in this case is DNA helicase
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    (Original post by Nixani)
    lynx i tink we only need to know the enzyme involved in unwindin n unzziping of dna double strand which in this case is DNA helicase
    I thought it was the other way around. RNA Polymers and Ligase we need to know mainly?
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    in the process of tissue culture, why are the explants placed in a sterile growth medium containing sucrose? i know its to stimulate mitosis but why sucrose?

    also could someone please give a quick outline of mitosis, have a feeling it will come up...
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    (Original post by _lynx_)
    It's not ligase is it? :confused: I really need to look over this topic.
    its ligase indeed:p:
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    (Original post by mikey_g)
    In transcription only the hydrogen bonds are broken, the sugar-phosphate backbone remains intact. I think the hydrogen bonds form back together without the need for an enzyme, so don't worry!
    DNA ligase is used to reform the sugar phosphate backbone when you're cutting plasmids / genes etc
    Ah of course!! Thanks for clearing that up for me

    Will rep tomorrow when I can.

    Spoiler:
    Show
    if I remember that is :p: Please do remind me.
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    (Original post by Remarqable M)
    its ligase indeed:p:
    Huh?

    I need to get off TSR and just sleep! :eek3:
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    huh?! can someone please define sustainability in simple terms???
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    I'm gonna put it out there and say that f215 is probably the most amount of information i'l ever be asked to retain at any one point in time and that's including my ginormous history exam on the same day. It's just so frustrating. Whenever I learn one thing, the other slips out of my head.
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    (Original post by thekooks)
    in the process of tissue culture, why are the explants placed in a sterile growth medium containing sucrose? i know its to stimulate mitosis but why sucrose?

    also could someone please give a quick outline of mitosis, have a feeling it will come up...
    sucrose can be broken down into glucose which is then used as a respiratory substrate; aerobic respiration which provide energy (ATP) for cellular processes such as cell division, protein synthesis etc etc




    when you look at it, mitosis is so goddamn easy in comparison
    differences include: bivalents do not form in mitosis, there's no crossing over of chromatids, no independent assortment of chromosomes, there's only 1 division, and it produces 2 diploid (as well as genetically identical) cells. JILUSDUIJSDIUJSOIUJO goddamn
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    Arghhhh!!!
    doing the past papers
    i swear, i write the points all given in the text book but they dont seem to be in the mark scheme -.-
    im so gunna fail
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    (Original post by s_a_r_a)
    huh?! can someone please define sustainability in simple terms???
    the definition from my economics is: "to provide for the needs of today without sacrificing the needs of tomorrow"

    I'm not up to it in biology, so it might well be different.
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    anybody????
 
 
 
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