Translation (mRNA to protein) | Biomolecules | MCAT | Khan Academy

Translation (mRNA to protein) | Biomolecules | MCAT | Khan Academy

100 Replies to “Translation (mRNA to protein) | Biomolecules | MCAT | Khan Academy”

  1. Good old Sal! Love his voice. These vids got me through my nursing prerequisites. Couldn't have done it without him. This is gold.

  2. This stuff blew my mind when I started my biochemistry studies. It still does. The deeper you go to the mechanics, more impressive it becomes.

  3. Nice video. Some people may not know but proteins make up the majority of the biopharmaceutical market for use as a therapeutic

  4. why there's no subtitles on your website?? please put subs on your website too, it's would helpful so much
    btw love your vids 🙂

  5. you are such a honorable teacher. you have made a student like me have the opportunity to all this beautiful knowledge. you sound so passionate! i really admire how you digest the information!

  6. Hi.
     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. Thanks

  7. This is wonderful. Thank you for a simplified version of translation. Sometimes i prefer watching these summarized videos than reading a book..But i got a question in relation to the 'E, P, A' sites how is it possible that we have an Exit on the 5' yet the mRNA is run thru the ribosome from 5' 3' direction ..Can you assist on that maybe i missed it

  8. at 12:11, I think you meant to say "then the A-site will be open for another tRNA carrying an amino acid" instead of "for another amino acid carrying tRNA"!

  9. it's such a well made video, thanks for the hard work! but gooooooooooosh this is so musch to handle for high school! XD

  10. Beings there can be 64 possible combinations of codons but there are only 22 amino acids does that mean that life on earth is still early on in its evolution and more complex organisms with more amino acids could exist in the future or on other planets?

  11. God bless Khan. I literally felt like i was on heroin during my lecture today when the prof was going on about transcription/translaition

  12. Had to write a 1 page summary of this for my biology teacher. A simple 14 minute video, will be the reason I'm not getting any sleep tonight.

  13. This is the most clearly explained video on translation I have watched. Simplifies the complex concept. Thank you Khan Academy and the tutor.

  14. So if of the 3 billion (500m?) base pairs in DNA, only 25k (2%) gets coded by RNA.. what determines what sections of the dna are genes? Non-coding micro-RNA? Is there any theory as to what the remaining junk/satellite dna was/is used for?

    On the recent After-On Podcast, Floyd Romesberg mentions how even though DNA has only 4 letters to work with, and therefore has a maximum 64 instructions (3 letter LUT)… of the 500 hundred naturally occurring amino acids, all life forms as we know it, draw upon only ~20 of these amino acids to make proteins! Plus, some of these amino acids are similar to each other, so the basic building blocks for life on earth isn't very diverse as one might expect. I assume the 37 genes in the mitochondrial DNA (mtDNA) also select from these same 20 to make it's 2 rRNAs, 22 tRNAs and 13 polypeptides? BTW, the reason different codons map to the same amino, could be to slow-down the rate at which the protein exits the ribosome factory!

    Incidentally, what I didn't understand from that podcast, is that if Floyd's lab has already developed special Transfer-RNAs that re-assigns a couple of the redundant STOP instructions (amber, ochre, opal) to fetch a new amino instead, then why isn't this enough to synthesize a new protein? Why did Floyd's lab also need to expand the DNA alphabet with 2 new Nucleobases (X, Y)?

    What about the processes that control the expression of genes, specifically "epigenetic inheritance". Is it possible mother-nature lifts some of the natural selection burden placed on a species, by allowing acquired traits to be passed in the germ line (sperm/egg), ala Lamarckian, like Nessa Carey suggests. Or is the idea a little half-baked like Steven Pinker says? BTW, Radiolab had a good epigenetic episode that talks about the 1836 famine data in Norway.

    Also, how does RNAi/RISC complex (microrna , smallrna, etc ) fit into all this.. is that what is considered to be responsible for germline epigenetic changes?

  15. Great video, explains tRNA and mRNA interactions so well. My mind can visualize it smoothly now. Also, super interesting fact about the antibiotics at the end!

  16. This Teacher's voice is super cool and he clears all my doubts and bdw the only reason I love Khan academy's biology part is due to this Teacher's voice

  17. I love that every video he does he is as fascinated with the complexities of these structures and processes. Now I pick up plants, give them to friends, and ask, what do you see? If they aren't as passionate and appreciative as this man, I cut them off.
    What is your name Sir? You are amazing!!

  18. Video starts at 9:00 for me, too long of an intro for very basic information that anyone browsing this video already knows. Just get to the point.

  19. Perfect explanation. My biochemistry book has a terrible depiction of this. And this visual is perfect that I understand exactly what is happening. Thank you!

  20. Thank u soo much… Ur explanation nd teaching method is awesome…. I loved it… Nd I'm never gonna forget this…😉

  21. God bless khan academy T.T I'm a visual learner and this is just beyond awesome!! I'm understanding, learning, AND I'm inspired by the passion of this teacher!

  22. I've always had this problem with these sites in ribosome, like what are they exactly and what are they for?- and now it's clear. Sal you are a blessing ♥

  23. Great video. When I was studying biology at the University of South Florida in 1967 as part of the pre-dental curriculum we learned the basics of which to build upon. Dr. Jerome Krivanck was the best teacher I ever had the pleasure of meeting. Advances in molecular biology will continue to improve the human condition. Congratulations to the professors and teachers who contribute to our understanding.

  24. In prokaryotes and eukaryotes, the basics of elongation of translation are the same. In E. coli, the binding of the 50S ribosomal subunit to produce the intact ribosome forms three functionally important ribosomal sites: The A (aminoacyl) site binds incoming charged aminoacyl tRNAs. The P (peptidyl) site binds charged tRNAs carrying amino acids that have formed peptide bonds with the growing polypeptide chain but have not yet dissociated from their corresponding tRNA. The E (exit) site releases dissociated tRNAs so that they can be recharged with free amino acids. There is one notable exception to this assembly line of tRNAs: During initiation complex formation, bacterial fMet−tRNAfMet or eukaryotic Met-tRNAi enters the P site directly without first entering the A site, providing a free A site ready to accept the tRNA corresponding to the first codon after the AUG.

    Elongation proceeds with single-codon movements of the ribosome each called a translocation event. During each translocation event, the charged tRNAs enter at the A site, then shift to the P site, and then finally to the E site for removal. Ribosomal movements, or steps, are induced by conformational changes that advance the ribosome by three bases in the 3′ direction. Peptide bonds form between the amino group of the amino acid attached to the A-site tRNA and the carboxyl group of the amino acid attached to the P-site tRNA. The formation of each peptide bond is catalyzed by peptidyl transferase, an RNA-based ribozyme that is integrated into the 50S ribosomal subunit. The amino acid bound to the P-site tRNA is also linked to the growing polypeptide chain. As the ribosome steps across the mRNA, the former P-site tRNA enters the E site, detaches from the amino acid, and is expelled. Several of the steps during elongation, including binding of a charged aminoacyl tRNA to the A site and translocation, requires energy derived from GTP hydrolysis, which is catalyzed by specific elongation factors. Amazingly, the E. coli translation apparatus takes only 0.05 seconds to add each amino acid, meaning that a 200 amino-acid protein can be translated in just 10 seconds.

    The termination of translation occurs when a nonsense codon (UAA, UAG, or UGA) is encountered for which there is no complementary tRNA. On aligning with the A site, these nonsense codons are recognized by release factors in prokaryotes and eukaryotes that result in the P-site amino acid detaching from its tRNA, releasing the newly made polypeptide. The small and large ribosomal subunits dissociate from the mRNA and from each other; they are recruited almost immediately into another translation init iation complex.

  25. During and after translation, polypeptides may need to be modified before they are biologically active. Post-translational modifications include:

    removal of translated signal sequences—short tails of amino acids that aid in directing a protein to a specific cellular compartment

    proper “folding” of the polypeptide and association of multiple polypeptide subunits, often facilitated by chaperone proteins, into a distinct three-dimensional structure

    proteolytic processing of an inactive polypeptide to release an active protein component, and

    various chemical modifications (e.g., phosphorylation, methylation, or glycosylation) of individual amino acids.

  26. Guys, I am still puzzled with one question: So we have Chromosomes -> DNA in a nucleus of the cell. Then, we have Translation phase where we get Proteins, but where do Proteins live? Do they live inside the cell (cytoplasm) ? So each cell creates it's own Proteins or each cell creates different proteins and they leave the cell and work 'outside' the cell? And in this case, what is 'outside' the cell? Any material/video, explaining this are more then welcome!

  27. so where does the trna come from? I understand the mrna is synthesized from the dna via polymerase. but it seems like the trna just comes in out of nowhere.

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