Bertybassett
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Hi, so in transcription and mrna production, i was wondering if someone could explain exactly what rna polymerase does. i know that it joins the nucleotides, but how does it do this? also, i know that it unwinds the double helix of the dna, but how does it do this also - by breaking the H bonds between complementary base pairs? many thanks
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Bio 7
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(Original post by Bertybassett)
Hi, so in transcription and mrna production, i was wondering if someone could explain exactly what rna polymerase does. i know that it joins the nucleotides, but how does it do this? also, i know that it unwinds the double helix of the dna, but how does it do this also - by breaking the H bonds between complementary base pairs? many thanks
DNA Helicase, if I remember this right, uncoils and opens the DNA chain so nucleotides can be added and RNA Polymerase acts upon the molecules to cause hydrogen bonds to form between the nucleotides.
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SpicyMemes69
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DNA Helicase is the enzyme that uncoils the double helix, so that RNA polymerase can catalyse the addition of free RNA nucleotides (A,U,G,C) in the 5' to 3' prime direction making a complementary single stranded mRNA molecule. It joins the nucleotides by hydrogen bonding between complementary bases. Hope this might help
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Bertybassett
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(Original post by Bio 7)
DNA Helicase, if I remember this right, uncoils and opens the DNA chain so nucleotides can be added and RNA Polymerase acts upon the molecules to cause hydrogen bonds to form between the nucleotides.
i dont believe this is correct
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Bio 7
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(Original post by Bertybassett)
i dont believe this is correct
It isn't detailed but exactly what is actually wrong since you didn't know it to start with?
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Bio 7
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(Original post by Bio 7)
It isn't detailed but exactly what is actually wrong since you didn't know it to start with?
Wait I'm thinking of DNA Replication. Nevermind me.
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HateOCR
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(Original post by Bertybassett)
Hi, so in transcription and mrna production, i was wondering if someone could explain exactly what rna polymerase does. i know that it joins the nucleotides, but how does it do this? also, i know that it unwinds the double helix of the dna, but how does it do this also - by breaking the H bonds between complementary base pairs? many thanks
RNA polymerase catalysis the reaction for the formation of temporary H-bonds between the RNA nucleotides and the DNA strand (template strand). It doesn’t unwind the DNA strand as far as im aware - gyrase does that.
Helicase breaks the H-bonds between the DNA bases.
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Jpw1097
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(Original post by Bertybassett)
Hi, so in transcription and mrna production, i was wondering if someone could explain exactly what rna polymerase does. i know that it joins the nucleotides, but how does it do this? also, i know that it unwinds the double helix of the dna, but how does it do this also - by breaking the H bonds between complementary base pairs? many thanks
RNA polymerase has intrinsic helicase activity, and so it can unwind DNA by itself - it does not need another enzyme to do this. Yes you are right, it does this by breaking the hydrogen bonds between complementary base pairs in the DNA strands. RNA polymerase II catalyses the formation of phosphodiester bonds - NOT hydrogen bonds - between the free 3'-OH group and the phosphate group on the 5' carbon on the adjacent nucleotide, synthesising a messenger RNA (mRNA) strand in a 5' to 3' direction. Remember, in RNA, uracil replaces thymine.
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Carbon-14
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Hello, RNA polymerase just creates phosphodiester bonds between the RNA nucleotide creating that strand of RNA,
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Bertybassett
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(Original post by Jpw1097)
RNA polymerase has intrinsic helicase activity, and so it can unwind DNA by itself - it does not need another enzyme to do this. Yes you are right, it does this by breaking the hydrogen bonds between complementary base pairs in the DNA strands. RNA polymerase II catalyses the formation of phosphodiester bonds - NOT hydrogen bonds - between the free 3'-OH group and the phosphate group on the 5' carbon on the adjacent nucleotide, synthesising a messenger RNA (mRNA) strand in a 5' to 3' direction. Remember, in RNA, uracil replaces thymine.
thanks for the reply - what does create the hydrogen bonds then? and also, doesn't helicase break the h bonds and unwind the strand?
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Jpw1097
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(Original post by Bertybassett)
thanks for the reply - what does create the hydrogen bonds then? and also, doesn't helicase break the h bonds and unwind the strand?
Helicase is only used to separate the DNA strands during DNA replication. RNA pol II has intrinsic helicase activity. The hydrogen bonds between complementary base pairs form spontaneously.
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username2858058
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Ignore the posts about dna helicase.

In eukaryotic transcription, RNA pol II unwinds the DNA and catalyses the synthesis of mRNA

This is with assistance of a whole load of other things, including various transcription factors, formation of a pre-initiation complex, formation of a transcription bubble, elongation complex etc., but you don't really need to worry about this
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