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    (Original post by heartskippedabeat)
    Selective breeding and evolution by natural selection both change the allele frequencies in the next generation, so the alleles that code for the beneficial or desirable characteristic will be passed on to offspring and become more common in the next generation. If a random mutation produces an allele that is beneficial or desirable, it will be selected for it the next generation, either because it increases the organism's chance of survival, or because it is useful to humans.

    However, in natural selection, the organisms that reproduce are selected for by the environment, whereas in selective breeding this is carried out by humans. Natural selection gives an unpredictable result, but artificial selection aims for predetermined results. Natural selection makes the species better adapted to the environment therefore increasing it's chances of survival, reproduction, and passing on the advantageous allele to the next generation. Artificial selection however, does not benefit the organism, it just makes it more useful to humans.

    It's not very detailed :/ Do you think that's okay?
    Yeah it's pretty detailed included most of the terms needed in markscheme to
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    (Original post by rebeccalouise_92)
    ahh i see, aww im sure u will go up! and it will be good revision for this course seeing as its synaptic? synoptic...or whatever the word is that means they can test us on previously learnt things! have you alraedy done the resit?
    Yeah I thought that, but no the resits next week :/ i wish they'd put it before this module cos it would've made a lot more sense I haven't started revising for it even though i know this ones synoptic but i don't want to get mixed up and this ones the more important one because its 25%

    (Original post by tesha_al)
    Yeah it's pretty detailed included most of the terms needed in markscheme to
    Haha yayy thank you
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    (Original post by heartskippedabeat)
    Haha yayy thank you
    would you like another?
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    whats the definition for transcription factors?
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    (Original post by tesha_al)
    would you like another?
    Yes please if you don't mind haha
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    (Original post by sportycricketer)
    whats the definition for transcription factors?
    what exactly do you mean? the unwinding and unzipping.....
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    (Original post by sportycricketer)
    whats the definition for transcription factors?
    not sure if this is completely right but

    The regulatory gene in an operon codes for a transcription factor – a protein that binds to DNA and switches genes on or off by increasing or decreasing transcription rate. The shape of a transcription factor determines whether it can bind to DNA or not, and can be altered by the binding of some molecules such as hormones and sugars.
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    (Original post by tesha_al)
    what exactly do you mean? the unwinding and unzipping.....
    do we not need to know the definition for transcription factors?
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    (Original post by heartskippedabeat)
    Yes please if you don't mind haha
    explain how knowledge of particular genes can be used in the filed of modern medicine? 4 marks
    outline the formation of recombinant DNA? 3 marks
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    (Original post by sportycricketer)
    do we not need to know the definition for transcription factors?
    maybe what above said ^.. i have no clue. dammit!
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    (Original post by sportycricketer)
    whats the definition for transcription factors?
    aren't they just activators that increase transcription and repressors that decrease transcription?
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    Right guys seriuosly Im so stressed. My dad has been ill lately and I havent been able to find time to revise beause of course family comes first. And anyway the bulk of revison I was going to do tonight and tomorrow as just gone out of the window and found outsome bad news. Anyone got any idea if I can get some consideration? My lifes a mess atm
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    (Original post by slacker07906)
    Right guys seriuosly Im so stressed. My dad has been ill lately and I havent been able to find time to revise beause of course family comes first. And anyway the bulk of revison I was going to do tonight and tomorrow as just gone out of the window and found outsome bad news. Anyone got any idea if I can get some consideration? My lifes a mess atm
    I'm sorry to hear this. Maybe you could contact your uni's and let them know about your circumstances, or ask your school what you or even they could do to help you, because of course, obviously like you said family are priority, but you don't want to miss out on your university place
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    (Original post by tesha_al)
    explain how knowledge of particular genes can be used in the filed of modern medicine? 4 marks
    outline the formation of recombinant DNA? 3 marks
    ahh not sure what to talk about exactly in this one, i tend to just write everything i can think of in exams so i think i'd say this:
    Gene therapy could be used to cure genetic disorders e.g. cystic fibrosis. It involves altering alleles in body cells, particularly those that are most affected by the disorder. Gene therapy could prolong the lives of people with genetics disorders and give them a better quality of life
    DNA probes can be used to identify DNA fragments that contain specific sequences of bases. For example, they can be used to locate genes on chromosomes or see if a person’s DNA contains a mutated gene that causes a genetic disorder.



    The DNA fragment containing the desired gene is isolated using restriction enzymes. The DNA fragment is inserted into vector DNA. The vector DNA is cut open using the same restriction enzyme that was used to isolate the DNA fragment, so the sticky ends of the vector are complementary to those of the fragment. The vector DNA and DNA fragment are mixed together with DNA ligase, which joins them by their sugar-phosphate backbones. The new combination of bases in the DNA (vector DNA and DNA fragment) is called recombinant DNA.

    Not sure about that one either
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    Has anyone else got a summary about the homeobox not sure if what I know about it is sufficient?
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    (Original post by joestevens2092)
    Just did Jan '11...What the hell was with that comparing PCR to in vivo or whatever one. Got 0/8 for that



    Thankfully grade boundaries were super low
    I saw that I was like wtf since they don't tell you anything about invivo in the book. Low grade boundaries will hopefully happen on monday too
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    Does anyone think auxins will come up?
    I'm thinking if they do, they could link it to the plant transport topic in AS because auxins move via phloem over long distances? I really hope they don't
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    (Original post by heartskippedabeat)
    ahh not sure what to talk about exactly in this one, i tend to just write everything i can think of in exams so i think i'd say this:
    Gene therapy could be used to cure genetic disorders e.g. cystic fibrosis. It involves altering alleles in body cells, particularly those that are most affected by the disorder. Gene therapy could prolong the lives of people with genetics disorders and give them a better quality of life
    DNA probes can be used to identify DNA fragments that contain specific sequences of bases. For example, they can be used to locate genes on chromosomes or see if a person’s DNA contains a mutated gene that causes a genetic disorder.



    The DNA fragment containing the desired gene is isolated using restriction enzymes. The DNA fragment is inserted into vector DNA. The vector DNA is cut open using the same restriction enzyme that was used to isolate the DNA fragment, so the sticky ends of the vector are complementary to those of the fragment. The vector DNA and DNA fragment are mixed together with DNA ligase, which joins them by their sugar-phosphate backbones. The new combination of bases in the DNA (vector DNA and DNA fragment) is called recombinant DNA.

    Not sure about that one either
    for second question that is basically it.

    for first 1)genetic testing for inherited diseases to see 2)if individual is a carrier and predict if potential offspring may inherit disease. 3) test for genes that contribute to diseases that may develop later in life and those with genes given advice to limit effects 4) earlier diagnosis so effective drug canbe developed to combat disease.
    I did this question with a mate and we said exactly the same as you
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    (Original post by heartskippedabeat)
    Does anyone think auxins will come up?
    I'm thinking if they do, they could link it to the plant transport topic in AS because auxins move via phloem over long distances? I really hope they don't
    why you gotta say that? I hated plant transport!!!!!!!!!!!!!!!!!!! it can be transported in the xylem too right? all i can remember is plant hormone gets transported by diffusion active transport and mass flow...explain them if you can my knowledge is a bit rusty.....
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    (Original post by Arab_Empress)
    Has anyone else got a summary about the homeobox not sure if what I know about it is sufficient?
    Body Plans – Genetic Control
    • Body plan = order of body parts. Designated in embryo. Controlled by homeotic genes.
    • Homeotic genes include hox genes – master switches, often coding for transcription factors.
    • They are read in the order they appear on the chromosome – if you put a leg gene where the antennae gene should be, you get a whole leg instead of an antenna, even though only one gene was changed.
    • They are conserved in animals – all have them = evidence for evolution. Put a mouse eye gene into a fly chromosome, in the right place and you get a fly eye, not a mouse eye.
    • Study of it uses organisms that:
    - Are similar to us in terms of cells, tissues and genetic make up.
    - Are easy to experiment with – reproduce quickly, cheap to keep, produce lots of embryos at once, have known mutations that we understand, show mutations easily.

    Thats what I've got on my notes hope it helps
 
 
 
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