Translation (mRNA to protein) | Biomolecules | MCAT | Khan Academy December 2, 2019 100 By Kody Olson Related posts: Khan Academy’s 100&Change proposal: World-class diplomas for anyone, anywhere Transcription and mRNA processing | Biomolecules | MCAT | Khan Academy Terms of Trade and the Gains from Trade | AP Macroeconomics | Khan Academy Khan Academy Live: SAT Math CategoryArticles BlogTagseducation learning lessons online learning 100 Comments Sairy Demesa says: September 27, 2016 at 7:38 am thanks for making this feel simple 🙂 the book gets real wordy. Reply icaa ss says: November 1, 2016 at 5:21 am why there's no subtitles on your website?? please put subs on your website too, it's would helpful so muchbtw love your vids 🙂 Reply Kika Sousa says: November 7, 2016 at 9:53 am Not gonna fail molecular bio thanks to this 🙏 Reply john tindell says: November 7, 2016 at 6:18 pm 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! Reply Grace Gable says: November 8, 2016 at 8:55 pm Great video, I will definitely pass my Cell Bio exam tomorrow! Reply Nutsa Tskip says: November 11, 2016 at 5:00 am i love you for making these videos. such a life saver Reply Music today says: December 5, 2016 at 1:07 am this lesson needs more explanation and a lot of reactions are not mentionned thank you any way 🙂 Reply Kalkidan Semere says: December 12, 2016 at 4:46 pm Life saver as always. Thanks Sal khan!!! Reply JJ says: December 16, 2016 at 10:24 pm Thank you so much!!!! Reply Rana Yasser says: December 24, 2016 at 3:24 pm Thanks alot.. that's so helpfull 👌👍👍 Reply Zainab Al Radi says: December 29, 2016 at 4:44 pm if I passed my premedical year I would dedicate my certificate to you <3 Reply Dina Saad says: January 6, 2017 at 4:50 pm THANK U! My brain was frying up trying to understand this by myself. Reply AB says: January 14, 2017 at 1:30 pm Good job Reply Theek. Weerasinghe says: February 3, 2017 at 1:07 pm Thnk u so ok much… Reply Keegan Andersen says: February 17, 2017 at 5:43 am Super helpful! Reply Aashi Thapa says: March 6, 2017 at 4:14 am You are Amazing. Thank you so much 😊 Reply Sourav Ghosh says: March 26, 2017 at 2:58 pm nice Reply Kevin Lin says: April 10, 2017 at 2:57 pm No mention of tRNA synthatase or initiation factors? Reply Leyla Abdullayeva says: April 14, 2017 at 4:43 pm 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 Reply omarreza420 says: April 16, 2017 at 9:10 am complicated process it's a whole process how does it know to do that its amazing Reply Kumbirai Deon says: April 22, 2017 at 4:59 am 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 Reply Kinley Tenzin says: April 24, 2017 at 1:47 pm Can you do the termination too 😉 Reply Study everyday says: May 17, 2017 at 10:14 am Proofreading? 🙁 Reply Valery Rose says: May 20, 2017 at 6:35 pm awesome Reply Miko Jiang says: May 25, 2017 at 12:01 am Than you SO MUCH for making this video!!! This helps a lot!!! Reply Marco Ferreira says: June 4, 2017 at 10:21 pm you can call the A-site as the arrival site Reply Yuser Alhaj says: July 4, 2017 at 9:10 pm Thanks man, really helpful Reply Raina Sajid says: July 9, 2017 at 5:55 pm Best! Reply Biruk Amare says: July 30, 2017 at 6:49 pm brillant explaination! Reply Isabella Kim says: August 4, 2017 at 11:48 pm 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"! Reply Aiza Saed says: August 15, 2017 at 1:02 am thank you!! finally get it Reply heey pal says: September 2, 2017 at 11:13 pm thank you so much!!! so so much!! ps. i love your voice 😀 Reply WATCH SNSD-I GOT A BOY ! says: October 6, 2017 at 11:55 am it's such a well made video, thanks for the hard work! but gooooooooooosh this is so musch to handle for high school! XD Reply Ali Hassan says: October 29, 2017 at 1:23 pm You are a great teacher😍 Reply Gaurav Karna says: October 29, 2017 at 4:21 pm make a nobel prize for education, and give it to this man. Reply Dude's Disciple says: October 31, 2017 at 1:51 pm You guys make it all so much more beautiful. Thanks Khan Academy, I'll do well thanks to you. Reply Anuj Verma says: November 13, 2017 at 11:20 am thank you sir Reply P Begum says: November 15, 2017 at 12:44 pm awesome. i really got it now perfectly. Reply Ivy Zhang says: November 26, 2017 at 2:36 am He is so cute! Reply Pavel Lambracht says: November 26, 2017 at 10:59 pm So, theoretically all proteins start with Methionine? Reply riggidy rickt says: December 1, 2017 at 6:30 pm You teach a lot better than my biochemistry professor! Class is pretty much useless for me Reply LuvElaYay says: December 14, 2017 at 8:15 pm brilliant Reply Tree Sprout says: December 18, 2017 at 2:13 pm Love it, science is simply amazing Reply wali zurmati says: December 28, 2017 at 2:34 pm Thanks a lot, you are the real teacher. Reply TankP0wnz says: January 18, 2018 at 5:56 pm That part at the end about how abx work blew my mind Reply S. P. Majumder says: January 20, 2018 at 12:56 pm Too much confusing in the last 3 minutes.hafazard.. Reply Vivixxjhobie says: January 25, 2018 at 2:57 am passed thanks to you .. Reply keeperofthegrove says: January 26, 2018 at 8:08 pm 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? Reply Petros Lazanis says: February 10, 2018 at 11:09 pm God bless Khan. I literally felt like i was on heroin during my lecture today when the prof was going on about transcription/translaition Reply Damein D'souza says: February 23, 2018 at 1:09 pm Many things missing as per NEET syllabus. But still helped me. Thanks. Reply Danger Girl says: March 25, 2018 at 5:53 pm thank you soooo much i like your videos Reply Sachit Koirala says: April 18, 2018 at 12:45 pm This is the most clearly explained video on translation I have watched. Simplifies the complex concept. Thank you Khan Academy and the tutor. Reply Maranda Martinez says: April 29, 2018 at 11:15 pm 5:06 LOL Reply Sofia Izaguirre says: May 3, 2018 at 6:17 am i owe you my degree. thank you. Reply Violin Santhosh says: May 20, 2018 at 6:43 am Thanks lots it really helped! Reply David C. says: May 23, 2018 at 5:15 pm we can do this fellow learners! Reply johnkevin1104 says: June 27, 2018 at 4:33 am what about specific steps for initiation, elongation, and termination Reply Ben Nguyen says: June 30, 2018 at 4:48 am 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?http://principlesofmolecularvirology.blogspot.com/2013/11/the-great-rna-confusion-rnai-mirna.html Reply Payal Rathod says: July 9, 2018 at 7:01 am taught very nicely…really😀😁😁💕 Reply Jennifer Allison says: July 25, 2018 at 12:56 pm Sal Khan you are a magnificent human being. Reply Fatema El Zahraa Said Mahmoud says: September 5, 2018 at 11:13 pm Thank you for teaching us how to love and appreciate biology ❤❤❤ Reply Luckyboy Oke says: September 16, 2018 at 12:10 am when an mRNA is expressed does that mean the encoded gene products have been expressed? Reply 马可小波罗 says: September 21, 2018 at 2:35 am Thank you. Reply Maaz Haji says: September 26, 2018 at 4:24 am 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! Reply BingBing BongBong says: September 29, 2018 at 8:40 am You’re cute :3 Reply Stefanie Belinda says: October 7, 2018 at 1:45 pm thank you so much it really helps me! Reply Najmah Chant says: October 10, 2018 at 2:37 pm AUA and UAU kinda look like cute emoticons Reply Yash sONi says: October 16, 2018 at 11:26 am 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 Reply Mohammed Burhan Uddin says: October 21, 2018 at 6:49 pm Brilliant sir Salman khan😍From Bangladesh! Reply Anonymous says: October 30, 2018 at 4:51 pm Who is the narrator? Reply Mahmod Samir says: November 2, 2018 at 4:27 pm how antibiotics differntiate between ribosomes of human and bacteria ? Reply JourniFar says: November 23, 2018 at 8:40 pm 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!! Reply Sam Ryan says: November 28, 2018 at 8:13 pm There's only 20 amino acids!!! not 22… Reply techforever1970 says: December 4, 2018 at 12:16 pm 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. Reply Morgan Alston says: December 7, 2018 at 4:25 am 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! Reply Roger gr says: January 6, 2019 at 5:37 pm so how would the t-RNA dettach its bond with the amino accid before it will shfit to the E site? Reply Joe V says: January 12, 2019 at 1:11 am Hands down the best possible explanation I have ever heard. You are a blessing to mankind. Thank you. Reply Dimple Reddy says: January 21, 2019 at 2:28 pm Thank u soo much… Ur explanation nd teaching method is awesome…. I loved it… Nd I'm never gonna forget this…😉 Reply Kon Chittavong says: February 11, 2019 at 12:23 pm You are so good! Thank you for making this video. Reply Kani Navy3 says: February 25, 2019 at 8:31 pm This is so helpful Reply Josselyn Ramirez says: March 22, 2019 at 4:40 am Super helpful I now fully understand Reply Simren Jeon JKook says: April 1, 2019 at 1:19 pm Very nice Video…Thank you so much for This Reply Azizul Hakim says: April 8, 2019 at 10:32 am Thank Reply zaid anmar says: April 9, 2019 at 8:04 pm i wish you go to heaven man wherever its is love from iraq ❤ medicine university Reply Ruth Nicolas says: April 11, 2019 at 4:56 am 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! Reply Tasfia Jaman says: April 23, 2019 at 5:50 pm 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 ♥ Reply David Vine says: April 25, 2019 at 7:28 pm 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. Reply dana z says: May 8, 2019 at 1:16 pm thank you daddy sal Reply Rabea Ahsan says: May 17, 2019 at 4:07 am 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. Reply Rabea Ahsan says: May 17, 2019 at 4:15 am 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. Reply Tubhyam Roy says: June 7, 2019 at 4:19 am The best possible explanation u gave Hands up to this Reply M Wal says: June 22, 2019 at 12:59 pm Thank you! 🙂 Reply rebelCoder says: July 3, 2019 at 5:51 pm 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! Reply Haroon Tariq says: July 24, 2019 at 1:14 am Thank you Sir.You are always a Life Saver in Exam Reply YE'S TUITION says: August 3, 2019 at 12:09 am So useful Reply Zane Berry says: August 16, 2019 at 1:25 am 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. Reply Nimrada Silva says: September 17, 2019 at 4:24 am Saving my life yet again 🙂 Reply Moosiin says: September 17, 2019 at 7:53 pm I love you Reply Mim mim says: September 25, 2019 at 3:39 pm Wow cant believe i actually enjoyed science😂 great teaching Reply Farida Burenbeiya says: October 8, 2019 at 7:09 am This is so awesome and so clear!! You made this fascinating process come to life and this video wasn’t even animated!! Thank you sir for all you do!! Reply Leave a Reply Cancel reply Your email address will not be published. Required fields are marked *Comment Name * Email * Save my name, email, and website in this browser for the next time I comment.