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    (Original post by BiologyF325)
    It showed amino acids in boxes, each attached to a box with three nucleotide bases in it = a codon. In the OCR textbook the diagram for tRNA shows that at one end there are 3 bases which are the anticodon where the tRNA binds to a complementary mRNA codon, and there are 3 bases on the other end of the hairpin shaped molecule where an amino acid binds.
    It is just 100% wrong that an amino acid binds directly to the mRNA! The amino acids form peptide bonds with each other and then the ribosome dissociates. Surely it was tRNA, someone back me up here!
    Oh were the boxes attached? I didn't see that D: I thought it was just 2 rows along side each other.
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    (Original post by Crazydavy)
    What was the grade boundary for the January paper?

    Plus, what did people put to the question, 'what type of mutation is UUG' or whatever that question was? I put neutral since it would have a neutral effect but I'm not sure?
    was it 60/100 for an A raw marks? i think soooo

    i wrote silent mutation because it still coded for the same amino acid? right?
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    Nearly Cried :'(
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    (Original post by Crazydavy)
    What was the grade boundary for the January paper?

    Plus, what did people put to the question, 'what type of mutation is UUG' or whatever that question was? I put neutral since it would have a neutral effect but I'm not sure?
    I think that was point mutation.
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    (Original post by Crazydavy)
    What was the grade boundary for the January paper?

    Plus, what did people put to the question, 'what type of mutation is UUG' or whatever that question was? I put neutral since it would have a neutral effect but I'm not sure?
    I put a point mutation :confused:
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    (Original post by BiologyF325)
    It showed amino acids in boxes, each attached to a box with three nucleotide bases in it = a codon. In the OCR textbook the diagram for tRNA shows that at one end there are 3 bases which are the anticodon where the tRNA binds to a complementary mRNA codon, and there are 3 bases on the other end of the hairpin shaped molecule where an amino acid binds.
    It is just 100% wrong that an amino acid binds directly to the mRNA! The amino acids form peptide bonds with each other and then the ribosome dissociates. Surely it was tRNA, someone back me up here!
    I got tRNA too.

    Paper was pure ecology (the chapter I least revised) what happened to the sliding filament model, neuromuscular junctions, muscle tissue type, brain stuff and the proper gene stuff like PCR & electrophoresis!! and the meiosis question was worth a whopping 2 marks!
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    (Original post by BiologyF325)
    It showed amino acids in boxes, each attached to a box with three nucleotide bases in it = a codon. In the OCR textbook the diagram for tRNA shows that at one end there are 3 bases which are the anticodon where the tRNA binds to a complementary mRNA codon, and there are 3 bases on the other end of the hairpin shaped molecule where an amino acid binds.
    It is just 100% wrong that an amino acid binds directly to the mRNA! The amino acids form peptide bonds with each other and then the ribosome dissociates. Surely it was tRNA, someone back me up here!
    The codons are on the mRNA. The tRNA has the anti-codons that are complementary to the codons on the mRNA.

    I figured the diagram was showing a length of codons, i.e., mRNA.
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    For the question where it asked which 3 codons stop the polypeptide chain, (people have said they were confused about this on the spread) I'm pretty sure it was:
    - The two on the cycle that easily showed us they were stop
    - + AUG for methionine as it would have started the next polypeptide, meaning the last one stopped, as methionine always means start and stops the last one
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    (Original post by Crazydavy)
    Only a good idea if it means they had to make us do another paper or do something else about it, otherwise the grade boundaries would shoot up as some people haven't done it yet?
    Oh right, don't if thats the case, but surely anyone in isolation must have finished by now? Either way if you post the paper it may spread around and hopefully OCR will get annoyed and pissing them off is better than nothing ey?
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    (Original post by susan23)
    Hi bad!!!

    that was a **** paper I'm never going to get into uni...I actually want to burn down every single OCR centre in the country and stab the person who wrote the exam!!! where they at some ****ing farm yard holiday camp when they wrote the exam filling it with sheep and hedgehogs ****!! what are they playing at!! they did the same with unit 4 in january 2011 and now they did it again!! did they not learn their ****ing lesson in january....!! seriously hate the idea of exams,...such a waste of my life...I could be doing something so much more than commit to this bull**** !! you waste so much time and what do you get at the end??? bull****!!!!! The dream for the A* seems tooooooooooooooooooooooooooooooo ooooooooooooo impossible now. and their going to make unit 4 retake liKE tHIs tOo! well you know what im not revising cuz i bet ther gna put some random ambigious bull...like they do.


    for your sake
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    So like 3 marks on genetics?? oh my days what a joke! and then like 3 pages on the nitrogen cycle. they could have balanced it out a bit.
    i hated those questions about the ladybirds and stuff, they're just like ISA questions, not testing your knowledge of the topic you've spent hours revising :/
    For me it was a 'meh' exam - not super hard but not super easy.
    come on low grade boundaries!!!
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    (Original post by mortysteve)
    I don't remember what the question explicitly said, but I was pretty confident that it was mRNA and I didn't second guess myself. Oh well, time will tell.



    Selective pressure sounds like it should get a mark (that's what I said for the second one, in effect). Not sure about directional pressure though, especially seeing as it's directional selection. ;p

    I was half-guessing though, so I'm not sure!

    Ahhhh *******s!

    Such a rookie mistake! And knowing OCR they'll probably not accept that since they're a stickler for keywords :\

    Ah well At least I got one mark.
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    (Original post by Crazydavy)
    What was the grade boundary for the January paper?

    Plus, what did people put to the question, 'what type of mutation is UUG' or whatever that question was? I put neutral since it would have a neutral effect but I'm not sure?
    I put 'silent/synonymous mutation'. (which it was, which is also neutral but im not sure if they'd credit without the word silent?)
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    I just wrote substitution... Judging by the posts, I guess I'm wrong lol. Damn, this is depressing. I think I'll just play games for a few hours and forget about it.
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    (Original post by Crazydavy)
    What was the grade boundary for the January paper?

    Plus, what did people put to the question, 'what type of mutation is UUG' or whatever that question was? I put neutral since it would have a neutral effect but I'm not sure?
    I put substitution/point mutation.. Although many people go 'silent mutation', cos you had to look at the diagram.. and the change would result in the same amino acid.
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    (Original post by BiologyF325)
    For the question where it asked which 3 codons stop the polypeptide chain, (people have said they were confused about this on the spread) I'm pretty sure it was:
    - The two on the cycle that easily showed us they were stop
    - + AUG for methionine as it would have started the next polypeptide, meaning the last one stopped, as methionine always means start and stops the last one
    No. It's UAG, UAA and UGA.
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    I think it was mRNA because mRNA code for methionine is AUG which was what the circle diagram was referring to x
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    (Original post by casiogeek)
    I put a point mutation :confused:
    I wrote silent mutation as it substitutes a base but still codes for the same amino acid.
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    (Original post by BiologyF325)
    For the question where it asked which 3 codons stop the polypeptide chain, (people have said they were confused about this on the spread) I'm pretty sure it was:
    - The two on the cycle that easily showed us they were stop
    - + AUG for methionine as it would have started the next polypeptide, meaning the last one stopped, as methionine always means start and stops the last one
    There were definitely three 'stop' combinations on the diagram. Two shared to the first two letters, so there were only two 'stop' words on the outer ring, but three combinations if you read it correctly.
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    I don't think they asked you to refer to the spinny wheel diagram when they asked what UUC was. So point mutation should be alright.
 
 
 
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