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    (Original post by The TSR Star.)
    I know I'm totally butting in on everyone's questions but eh what the heck....

    I don't really get this question...can someone help me a bit?

    Explain how interspecific competition can impact on pop size and distribution.
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    Interspecific competition is the competition for resources (such as prey, space, water availability) between different species. If two species occupy a niche is that is similar, one species will eventually out compete the other, causing the population of the less adapted species to decrease significantly or even become extinct. The species that has outcompeted its competitor is the one deemed more adapted to the environment and is more likely to survive to reproductive age and will have a much larger population than the outcompeted species........


    Have I completely missed the point?
    No thats right...similar to what ive had said.
    The only thing id have perhaps added on was in certain areas conditions are different, thus one species may out compete the other more due to better adaption to that environment. Both population sizes will be reduced because they are competing for the same resource, and if one is better adapted then you get one species out competed (which you did mention).
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    Hey sorry to go off on a completely different point but im a bit confused about something, so we have to learn transcription and translation processes in detail, and this is to make proteins etc. do we need to know anything about normal cell devision as in mitosis? or is it linked to the transcription stuff? any help would be greatly appreciated!
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    Hi

    Does anyone have a summary on genetic engineering of Golden Rice? or someone could kindly identify the main points, ive got one but its slightly wordy and hard to remember.

    Thanks
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    (Original post by alimurphy)
    Hey sorry to go off on a completely different point but im a bit confused about something, so we have to learn transcription and translation processes in detail, and this is to make proteins etc. do we need to know anything about normal cell devision as in mitosis? or is it linked to the transcription stuff? any help would be greatly appreciated!
    yes to all
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    (Original post by alimurphy)
    Hey sorry to go off on a completely different point but im a bit confused about something, so we have to learn transcription and translation processes in detail, and this is to make proteins etc. do we need to know anything about normal cell devision as in mitosis? or is it linked to the transcription stuff? any help would be greatly appreciated!
    i dont think there is anything in the specification that says we need to know the processes in mitosis - just meiosis
    but of course the synoptic elements could mean that it comes up

    but YES we do need to know about transcription and translation in detail
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    (Original post by Archen)
    i dont think there is anything in the specification that says we need to know the processes in mitosis - just meiosis
    but of course the synoptic elements could mean that it comes up

    but YES we do need to know about transcription and translation in detail
    right thatnks for clearing that one up, you know when you have a really random question that's getting you confused!
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    Is it safe to revise and learn only what the specification asks ? Should I go beyond that ?
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    Anyone have a really challenging question? :P
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    (Original post by uer23)
    Is it safe to revise and learn only what the specification asks ? Should I go beyond that ?
    Well I've only ever learnt from the spec and my lowest score is 86% (unit 1 :sigh:). So....i think its safe.
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    (Original post by ViolinGirl)
    Anyone have a really challenging question? :P
    Gel electrophoresis and chromatography. similarities. go!
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    (Original post by The TSR Star.)
    Well I've only ever learnt from the spec and my lowest score is 86% (unit 1 :sigh:). So....i think its safe.
    So you got that by covering every single point on the spec ? Did you go beyond this to read around the subject areas ? Any other tips, how much past paper revision did you do ?
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    (Original post by mikey_g)
    Gel electrophoresis and chromatography. similarities. go!
    Hmm. I can't immediately think of many similarities but here goes...

    They are both separation techniques that relate to the size of the items present in the sample.
    They both require a medium in which the sample travels through.
    In both cases separation depends on the affinity the sample has for the stationary phase (the phase does not move) and this governs how fast/slow it moves across it (the mobile phase). For example in electrophoresis, the agrarose gel is the medium through which the fragments of DNA travel through. Longer pieces of DNA can be considered to have more affinity for this stationary phase and they will move through the agrarose gel less easily that shorter pieces.
    With both techniques you can conduct further analysis on the sample, in electrophoresis you can transfer sample to paper, by southern blotting, use probes to locate certain genes etc. With Chromatography, values can be looked up, and used to identify the unknown substances, e.g. RF values.

    Lol, I've done this more in terms of chemistry.
    I can't think of more...
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    hey gang, can anyone shed some light on a little thing for me?

    i know the process of BACs and how they're used to sequence the DNA...but can anyone tell me why they are placed in the BACs? what purpose does this do apart from producing loads of copies of it?

    so in other words i am asking: since the DNA is sheared, put into the BACs which is taken up by bacteria and lots of copies are produced...and then the BACS are treated with restriction enzymes and the fragments are cut and electrophoresis is used to seperate before being looked at under a computer...why do we need to make lots of copies? surely we can just take the DNA, use electrophoresis to seperate it and then look at it under a computer???

    any help will be appeciated!!
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    (Original post by uer23)
    So you got that by covering every single point on the spec ? Did you go beyond this to read around the subject areas ? Any other tips, how much past paper revision did you do ?
    As for the last three exams:
    - I knew the specification points
    - Knew basic synoptic
    - Only did past papers in the back of the purple book with the brain on
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    (Original post by aiden1234)
    hey gang, can anyone shed some light on a little thing for me?

    i know the process of BACs and how they're used to sequence the DNA...but can anyone tell me why they are placed in the BACs? what purpose does this do apart from producing loads of copies of it?

    so in other words i am asking: since the DNA is sheared, put into the BACs which is taken up by bacteria and lots of copies are produced...and then the BACS are treated with restriction enzymes and the fragments are cut and electrophoresis is used to seperate before being looked at under a computer...why do we need to make lots of copies? surely we can just take the DNA, use electrophoresis to seperate it and then look at it under a computer???

    any help will be appeciated!!
    But the computer finds the DNA sequence using overlapping fragments of DNA, that's why you need so many copies.
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    (Original post by The TSR Star.)
    But the computer finds the DNA sequence using overlapping fragments of DNA, that's why you need so many copies.
    oh so wait, is the whole genome sheared and then put into plasmids? or is it done in sections? so like one section has this process..see where it overlaps, then another section? :confused:
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    I need help on this one- please explain this dopamine stuff (bullet points would be appreciated)!
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    (Original post by aiden1234)
    oh so wait, is the whole genome sheared and then put into plasmids? or is it done in sections? so like one section has this process..see where it overlaps, then another section? :confused:
    The entire genome is sheared into smaller sections. These individual sections are inserted into separate BACs. So these BACs with different sections of the genome are then put into cells etc and then we get a clone library. After you get lots of them, you take the cells containing specific BACs and then remove DNA from all the cells and cut it into smaller sections using completely different restriction enzymes so you get different types of fragments. So then you use electrophoresis to separate the fragments. Used an automated sequencer (?) and then you compare the overlapping fragments with a computer.

    You never sequence the entire genome (well for this you dont), the computer only sequences the BAC sequence.....
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    (Original post by ViolinGirl)
    I need help on this one- please explain this dopamine stuff (bullet points would be appreciated)!
    OK this is how i think it goes:

    dopamine is a neurotransmitter that has been linked to many activities in the body and has a variety of effects on the body.

    Dopamine has such a variety of activities in the body because of the range of receptors. There are 5 dopamine receptors going from DRD1 to DRD5

    There are many different genes that code for the receptor DRD4. Because of the number of variants, some of the variants have been thought to affect the level and activity of dopamine.

    A number of studies have found the some of the variants of DRD4 have led to an increase in addictive behaviours such as smoking and gambling. A number of other studies have found variants of DRD4 are more likely to have sufferers of Schizophrenia.
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    (Original post by The TSR Star.)
    The entire genome is sheared into smaller sections. These individual sections are inserted into separate BACs. So these BACs with different sections of the genome are then put into cells etc and then we get a clone library. After you get lots of them, you take the cells containing specific BACs and then remove DNA from all the cells and cut it into smaller sections using completely different restriction enzymes so you get different types of fragments. So then you use electrophoresis to separate the fragments. Used an automated sequencer (?) and then you compare the overlapping fragments with a computer.

    You never sequence the entire genome (well for this you dont), the computer only sequences the BAC sequence.....
    aaaah ace thanks i was getting confused with the different BACs i didnt realise they had to be seperate ! thankyou!
 
 
 
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