Biochemistry MCAT Chapter 6: RNA (1/2)

Hello Future Doctors! This video is part of a series for a course based on Kaplan MCAT resources. For each lecture video, you will be able to download the blank and completed notes.
To find the notes, click on the following link:
drive.google.c...
If you have any questions or have specific problems that you would like to see in a problem set video, feel free to leave a comment below or email me at:
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I will reply as soon as possible since I am a busy graduate student. But ultimately, I would still like to be a resource for you to use. I only wish for your success.
Good luck. You got this. Happy studying!

[@niaallen4952]

Omg you are a lifesaver I definitely understand this a whole lot more since I’m more of a visual learner

[@professoreman2289]

I am so happy to hear that!!!

[@niaallen4952]

@@professoreman2289 do you have a playlist explaining organic chemistry for MCAT

[@elisasaenz7116]

so good!!

[@professoreman2289]

❤️❤️🥰

[@ismaelrosales5094]

Thank you so much professor Eman! Last video for tonight see you tomorrow!

[@professoreman2289]

Hope you enjoyed it!

[@A1T6J]

Thank You!

[@professoreman2289]

No problem!!

[@RP13433]

I thought that UAG was a stop codon not TAG? at 14:29

[@professoreman2289]

Hi! You ask a great question! Both are correct, depending on the context. TAG is the stop codon in DNA, while UAG is the corresponding stop codon in mRNA. During transcription, Thymine (T) in DNA is transcribed as Uracil (U) in RNA. So, while TAG is the sequence you'll find in DNA, UAG is what you'll see in the mRNA transcript. Both represent the same stop signal, just in different nucleic acid contexts. I hope that clarifies things :)

[@emanalasadi2835]

Notes and transcript are up!

[@professoreman2289]

!

[@ss-nu8xx]

Control of gene expression was so rushed. Way too much time spent on basic school level material like transcription and translation that are very basic. Should have put time instead on means to modify rna and the impact and the concept of operons

[@professoreman2289]

I'm sorry you feel that way, I try to focus more time on content that's higher yield while still covering everything in a digestible manner. Nevertheless, I could provide you more information on your suggestions:
There are more than 100 different types of chemical modifications that can be added to RNA after it's made, such as methylation (the addition of a methyl group, -CH3), pseudouridylation (conversion of uridine into pseudouridine), and adenylation (the addition of adenosine at the 3’ end, mostly seen in microRNAs).
These modifications can impact how the RNA molecule functions. For instance, modifications in messenger RNA (mRNA) can alter the rate of translation, the protein sequence, and mRNA stability. In tRNA and rRNA, modifications are crucial for their proper folding and function.
RNA modifications are involved in the regulation of various biological processes and can play roles in diseases. For example, a lack of certain modifications or the enzymes that catalyze these modifications can lead to neurological disorders and cancer.
Operons are functional units of DNA containing clustered genes regulated by a single promoter. They are common in prokaryotes but rare in eukaryotes. An operon is composed of structural genes, an operator gene, and a promoter gene. The structural genes are responsible for producing the protein. The operator is the region of DNA to which a repressor can bind. The promoter is a nucleotide sequence that enables a gene to be transcribed.
There are two main types of operons: inducible and repressible. An inducible operon, such as the lac operon in E. coli, is usually off but can be turned on when the specific inducer molecule is present. In the case of the lac operon, the presence of lactose induces the operon.
On the other hand, a repressible operon, like the trp operon also found in E. coli, is usually on and produces a product, but it can be turned off when the specific repressor molecule is present. In the trp operon, the presence of tryptophan, a product of the pathway, leads to repression of the operon.
The concept of the operon allows a bacterium to adapt to its environment. By coupling a specific environmental signal to the control of gene transcription, the bacterium can produce certain proteins only when they are necessary. This helps to conserve resources and increase efficiency.
RNA modifications and operons are both mechanisms used by cells to control gene expression and adapt to their environment. They highlight the complexity of genetic regulation and show that understanding these processes can provide insights into the basic biology, disease states, and potential therapeutic strategies.

[@rachelkurz7150]

thank you!

[@professoreman2289]

My pleasure friend 💕