The Trp operon demystified

Since VCAA told Victorian teachers that attenuation in the Trp operon was examinable - there has been a lot of discussion about the Trp operon and many questions raised about how attenuation actually works. The answers to some of these questions are elusive. All the videos and texts gloss over them (For example, how many ribosomes are involved? Does the ribosome need to get past the stop codon in the Leader, and the anti-attenuator loop? Are the structural genes translated into a single polypeptide and then cleaved into separate chains, or is each structural gene translated separately - and if so what is the mechanism for that? These are questions that go deeper than VCE students will need (I think) - but they are the sort of questions that keep us awake at night. Well, they keep me awake at night, anyway. This video answers those questions and more. It's detailed - but that's the purpose this time around... to make all those hard-to-make connections.

[steveholmes]

This is the best explanation of the tryptophan operon I have ever seen! There are no textbooks, there are no videos, there’s simply nowhere else we’re such a clear, concise and understandable explanation of the tryptophan operation is given. Please make more videos.

[oliverhair]

Crazy that I did this in Year 11 and now coming back to this video as a first year Biomedical Science student, this video is so detailed and clear! So helpful, thank you!!

[saramr-ingur]

You, kind sir, are absolutely saving my degree!

[DamithaSaththiyananthan]

I was looking for a video explaining the trp attenuation. Other videos were too short to explain everything in detail. With your explanation every step makes sense. Thank you so much!!

[katenicholls]

Your joy in this matches mine. I love your classes, and I'm so happy to have found your mega-helpful site. Thank you.

[cosdogy]

Andrew the legend! Thanks so much for helping me with VCE bio!

[hashifahizzatinadifan]

Thank you so much for explaining why the ribosome doesn't need to pass the hairpin!

[TheBrandedAffiliate]

Love this!!! Your edrolo lessons have helped me develop a love for biology and helped me enjoy school more thank you so much! Keep making this awesome content!

[raymorr_]

Coming from the online presentation you did recently, this was great to cement that information, thank you!

[malikbenmoumen]

I'm a biotechnology student, 3rd year Licence (frome Algeria). I'm having an exam of a module called Genetics éléments of micro organisms. This video really helped me to understand trp operon regulation. Thank you!

[midotah]

I have just one question, how is it possible that an explanation of such clearness and wonderfullness cant reach 182 million likes, if not more, in the same time other videos in youtube reach more than that, I rearly admire the way you explain this topic, I am saying this because I spent all the moorining looking for a video that explain TRP operon and atenuation process, and yours was so.... thank you

[sampatel]

exams are around the corner and this helped a lot... thanks 😶‍🌫🤩

[resonancerecordings]

Best explanation for this mechanism on YouTube! Thanks a lot!

[sophiedahlenburg]

Hello! Year 12 biology student here, quick question - just wondering why the stop triplet in the dna of the leader section does not cause RNA polymerase to stop transcription? because the stop codon causes the ribosome to stop translation, so how come the RNA polymerase can continue transcribing the mRNA past this? hope this makes sense, and thank you for all your awesome resources throughout the year :)

[farhanjamil]

Damn it! This is just awesome. Thanks man.

[gabrielazimbron]

Great video-- thank you!
I've got a follow-up question: If there are ribosome binding sites and start codons at the start of the structural genes, doesn't that make the attenuation part of this whole thing meaningless? The way my textbook explains it is that the whole point of the attenuator is to stop the ribosome from being able to continue on from the 5' UTR to the structural genes and translate them. It has no mention of the stop codon after region 1.
Thanks!

[joranerobert]

Wow! Amazing explanation! I hate memorizing steps in biology, there is a reason behind each steps and you were able to fill the missing information! Now, on the test, i will go based on logic, rather than relying on my fish brain!

[manashpratimdutta]

Please make more videos... you are amazing

[paddyobrien]

Hey Andrew, was wondering whether or not the trpL sequence (region 1) encodes mRNA that becomes useful in the cell? If so, then what does it do?

[HảiAnhTrần-xv]

i hav a question
Why does the ribosome not leave even though has met the stop codon