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    According to my book 'a gene is a length of DNA that codes for one (or more) polypeptides', but then it says that 'the operator and promoter are both genes as they are lengths of DNA, however they do not code for polypeptides'. But then wikipedia says that they're not genes 'Various short sequences that are not genes also affect gene expression, including the lac promoter, lac p, and the lac operator, lac o', so whose right? Or have I misinterpreted?
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    Genes code for proteins. The regulatory elements like promoters and operators are not genes, nor are they transcribed into mRNA.
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    (Original post by JohnnytheFox)
    Genes code for proteins. The regulatory elements like promoters and operators are not genes, nor are they transcribed into mRNA.
    But then why does my book say that they are genes? Or maybe it's trying to say that in one aspect it's a gene as it's a length of DNA but we can't call it that as it doesn't code for polypeptides?
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    anyone?
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    (Original post by celina10)
    But then why does my book say that they are genes? Or maybe it's trying to say that in one aspect it's a gene as it's a length of DNA but we can't call it that as it doesn't code for polypeptides?
    No idea. What book are you using? Each gene will have its own individual promoters, otherwise they won't get transcribed, so in that way you could say a promoter is part of a gene, but to say a promoter IS a gene is just wrong.
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    Operator and promoters are called regulatory sequences, because they regulate the activity of the gene. Proteins called Transcription Factors (TFs) will bind to the DNA at promotes sites and will stimulate transcription. They are not strictly speaking genes, rather regulatory sequences upstream of genes (Degree in Biomed) Just ask if you have more questions
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    (Original post by JohnnytheFox)
    No idea. What book are you using? Each gene will have its own individual promoters, otherwise they won't get transcribed, so in that way you could say a promoter is part of a gene, but to say a promoter IS a gene is just wrong.
    I'm using the OCR A2 textbook, and I agree. They're basically contradicting themselves, because they said that a gene codes for proteins. :confused: But it's in the 'key definitions' bit so I guess I'll just have to accept it and memorise it
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    (Original post by Albio1306)
    Operator and promoters are called regulatory sequences, because they regulate the activity of the gene. Proteins called Transcription Factors (TFs) will bind to the DNA at promotes sites and will stimulate transcription. They are not strictly speaking genes, rather regulatory sequences upstream of genes (Degree in Biomed) Just ask if you have more questions
    But then they said that the operator and promoter 'are both genes as they are lengths of DNA. however, they do not code for polypeptides'. So what are they trying to say in this sentence?

    I have a few more questions, if you don't mind. Is the regulatory gene (the one that codes for the inducer) part of the regulatory sequence? And why isn't the regulatory gene part of the lac operon?
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    What book are you looking at? if I read that somewhere I would disregard it as wrong tbh, but depends what book it is. The inducer I believe is a separate entity, coding for a distinct entity. It was a while since I did the lac operon, remember it confusing the hell out of me .
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    (Original post by Albio1306)
    What book are you looking at? if I read that somewhere I would disregard it as wrong tbh, but depends what book it is. The inducer I believe is a separate entity, coding for a distinct entity. It was a while since I did the lac operon, remember it confusing the hell out of me .
    I'm using the OCR A2 textbook (, the one given by our exam boards). So why isn't the regulatory gene part of the lac operon? And is the regulatory gene considered a regulatory sequence in the operon like the promoter and operator sequences are?
 
 
 
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