RNA polymerase or DNA helicase?????? And gene expression??????

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ilovefruit
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So during transcription in the nucleus, the DNA strand is 'unzipped' so the sequence of complementary bases can be copied and mRNA taken out of the nucleus and onto a ribosome. Is it DNA helicase which break the hydrogen bonds within the DNA or is it RNA polymerase? I though it was DNA helicase which break the hydrogen bonds/ or unzip, and the RNA polymerase which gather all the components to form the mRNA strand. Is this right, and please correct anything I've gotten wrong.

ALSO, what is the difference between the operator gene and the promoter region? Is it that: the repressor molecule attaches to the operator gene to prevent the RNA polymerase binding, but if the repressor molecule is absent, the promoter region is where the RNA polymerase will bind? Again please correct anything which is wrong, this kinda confuses me

Thank you
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SANTR
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(Original post by ilovefruit)
So during transcription in the nucleus, the DNA strand is 'unzipped' so the sequence of complementary bases can be copied and mRNA taken out of the nucleus and onto a ribosome. Is it DNA helicase which break the hydrogen bonds within the DNA or is it RNA polymerase? I though it was DNA helicase which break the hydrogen bonds/ or unzip, and the RNA polymerase which gather all the components to form the mRNA strand. Is this right, and please correct anything I've gotten wrong.

ALSO, what is the difference between the operator gene and the promoter region? Is it that: the repressor molecule attaches to the operator gene to prevent the RNA polymerase binding, but if the repressor molecule is absent, the promoter region is where the RNA polymerase will bind? Again please correct anything which is wrong, this kinda confuses me

Thank you
DNA helicase breaks the hydrogen bonds between the complementary nitrogenous base pairs.
RNA polymerase is involved in the formation of the mRNA strand i.e. the sugar phosphate backbone, it joins the nucleotides together.
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Valour10
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I believe in transription, it is actually the RNA polymerase that is responsible for both unwinding the helix and adding nucleotides together.
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macpatgh-Sheldon
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(Original post by Valour10)
I believe in transription, it is actually the RNA polymerase that is responsible for both unwinding the helix and adding nucleotides together.
Hi good to see your username implies courage young man - however, you have got this wrong.

DNA helicase breaks the hydrogen bonds between A and T AND between C and G in the respective chains that form the double helix - so helicase catalyses the unwinding of the helix (helix = spiral therefore helicase builds OR unwinds helix - you know that an enzyme can drive a reaction in either direction depending on the conditions e.g. pH, pressure, temp).

RNA polymerase makes the polymer RNA - hence, it catalyses the bonds between adjacent nucleotides making a polynucleotide = in this case RNA.

For the benefit of everyone, names in biology/medicine are given TO ITEMS FOR A REASON - NOT BECAUSE GRANDMA liked the name as in when baby is born: Michelle OR Kieran OR Holly OR Luke etc.
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awbs
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both break hydrogen bonds, but...
i think RNA polymerase creates transcription bubble...
while DNA helicase creates replication fork.

RNA polymerase also attaches floating nucleotides while moving across the strand. this is called 'elongation' but im not sure you need to know about that.

i think its easier to learn and remember things when looking at pictures/ animations. if you're having trouble there's this youtuber called 'Prof Dave Explains'. he's a great help.
Last edited by awbs; 1 year ago
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Whata
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RNA polymerase forms the phosdiester bonds between the nucleotides, joins them together to form mRNA.
DNA helically unwinds the dna by breaking down the hydrogen bonds
They do not both break hydrogen bonds
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tocka90
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2018 papers: https://www.youtube.com/playlist?lis...zBrc69Yr9zb6d_

All genetic topics for new section 4 and 8 here if you are still confused
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