Introduction to transcription including the role of RNA polymerase, promoters, terminators, introns and exons.
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Question about the 'unzipping' part of transcription:
My biology teacher told me that DNA helicase does this,
however my Chemistry teacher told me that RNA polymerase does this and helicase is only involved in replication.
Who is correct? :'( they're both great teachers.
EDIT: after a lot of googling it seems pretty much 50/50 to either helicase or polymerase - if anyone knows which one it actually is please let me know how you know lol and why lots of people are mistaken.
Any info would be really appreciated!
Can someone please explain to me how mRNA synthesis can begin on 3' end of antisense/template strand if all of the promoting sequences (CAT & TATA) are toward the 5' end of the molecule?
Is RNA polymerase reading both strands of the DNA molecule and only transcribing from the template strand?
thanks in advance!
Colton B polymerases only able to build 5'-3'. Transcription goes only 1 way becase of antiparallel law. Remember how much work must be done to rebuild second chain in DNA replication (Okazaki framents)? Also you can see he put operator on the left side, RNA polymerase doesn't care which chain is it, it only recognize the start (3' in this case). If it was upper chain polymerase would have to start at 5' and build 3'-5'.
Great video - thank you. I liked the very clear explanation of Ribosomal RNA (that it doesn't need anything else to code, compared to the DNA where it needs Helicase, RNA Primers, Ligase, etc.) I also really enjoyed learning about the difference between the mRNA in prokaryotes vs. Eukaryotes. It's interesing that the Introns do not have a specific purpose, so the mRNA, is made up of what's left over after the splicing takes place (exons) of that "pre- mRNA".
Again - I greatly enjoyed this video, thank you!
Do you ever just study cellular biology and think about how little we actually know about this shit...
like when you said, "the RNA complex changes" to let go of the strand, i thought, wow...
things don't just change but hes right cause that's what is taught because that's just how we perceive what is occurring under a microscope
In reality, the RNA polymerase is a holoenzyme that is located in a large pre-initiation complex (made up of RNA polymerase and 6 transcription factors). DNA helicase activity is found in TF2H. For simplicity, it is easier to say that in DNA replication there are distinct enzymes, like DNA helicase and topoisomerase that cause positive supercoiling and relieve that supercoiling via the introduction of negative supercoils, respectively. In transcription, it's easier to conceptualize that the RNA polymerase does it all itself, when in reality its a concerted effort by a variety of TFs in that complex. For the MCAT, which is the context of this video, the preinitiation complex is far too in-depth; however, in an upper-division biochemistry class, this is how it will be taught.
Another example of this is the TATA binding protein included in the pre-initiation complex which positions RNA poly II on the DNA template strand which is also left out of this video.
Hope this helps.
Based on theory you believe. In replication, if you believe conservative nor the semiconservative, there's no need helicase. But the fact that In transcription, it need halicase to separate that double helix. It's still intra-nucleus. So, helicase can be used in replication nor the transcription.
But basically, polymerase is the enzyme for copying mirror that nucleotide.
hi. just a question because i got confused. I am currently reading Harper's Medical Biochemistry. i usually watch your videos when i can't understand the book. According to Harper, the strand that is transcribed or copied into and RNA molecule is referred to as the template strand, and the other DNA strand, the non coding strand, is frequently referred to as the coding strand. I think you interchanged the terms in your video. Can you please clarify these things. Thank you so much!
i can a little bit speak Englisch . And very good german but you dont speak german i think. i write to you that you say me if you know it, with help which program i can create biology Pictures like in genetik? i mean Polymerases, Enzme, Proteine, and so on.
I wanna to know the name of this programm with help you create the video also. Please send me the download link.
The RNA being transcripted has the same sequence as the coding strand (with the Uracil replacing Thymine), BUT they don't have "the same information".
If the coding strand were being transcribed here, it'll give a different RNA sequence, therefore a different order of codons, which eventually gives different amino acids (different protein). So yeah, not the same information =)
thanks for the video, such a very good video :))
but just realized that all cromosome or nucleus or enzyme or even protein picture we see in our textbooks or internet just an animation, so it's must be very very complicated in the real life. yet that's all are fascinating things to know about
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