It should be noted that citrate does not contain acetyl-CoA, but simply acetyl. So the CoA-group is added to the citrate in the cytosol by the means of ATP-citrate lyase after the citrate is transported into the cytosol.
Like, you're right but it's irrelevant and ruins someone's understanding of the pathway. Acetyl-CoA makes citrate, and that's an important part of understanding where citrate comes from and why it is a good regulatory molecule for FA synthesis.
Requiring a citrate shuttle in order to get the acetyl-coA from mitochondria out into the cytoplasm seemed like a waste until we realized that once it breaks down to OAA and then to pyruvate, we get NADPH, which is essential to FA synthesis. The cell is such a well oiled machine!
This was so helpful, thanks! I agree with the small already made suggestions of clarifying that citrate doesn't actually contain acetyl-CoA but acetyl itself and also that the pdh is a complexe. also i've never heard of the nadph // oxalacetat --> pyruvat conversion. Instead I was taught that there is an exchange between malat and oxalacetat? Anyways, those are just minor things - and your voice is not annoying at all! I personally think it's super important for these rather long videos to not be to monotone. Without proper enunciation, which you clearly delivered, it just get's lenghty. Keep it up!
2:05....post meal.insulin drops and glucagon rises 1-2hours after a meal (thats correct) BUT glucagon's main effect is on liver not on adipose..Epinephrine and cortisol are the ones that mainly stimulate HSL in adipose(lipolysis) :-)
OAA is not converted directly to pyruvate, but first converted to malate which is the converted to pyruvate through malate dehydrogenase, and only in this reaction we earn that nadph you were talking about.
So when you consume fat from your diet, it eventually gets into your blood stream via chylomicrons. Can the triglycerides be then stored directly as fat in your adipose tissue? Or does it have to first go through glycolysis and turn into Acetyl-CoA and then back to Triglycerides via Fatty Acid Synthesis?
Thanks for your excellent videos. Can you very kindly clarify the following. Can dietary fat only be burnt by mitochondria if it has first been ‘processed through’ fat cells and released as FFA? Or can mitochondria also burn dietary fat that hasn’t come from a fat cell? Thanks for any comments.
Hi Kyle, you say: "all Fat will be burned in the mitochondria, however yours is more of a question of Fatty acid transport. Basically your mitochondria will burn fatty acid chains from whatever source they can get them from if the hormone Glucagon is present. whereas if insulin is present it will be stored in adipose. Bear in mind that a small amount of fatty acids will travel around in the blood as part of your VLDL and also attached to Albumin." You seem to be saying that mitochondria can burn fatty acids even if they have not been released by (come from) fat cells as 'free fatty acids'. Please clarify. My question is simple: apart from glucose, can mitochondria only burn FFA's released by fat cells, or can mitochondria also burn fatty acids that have not been processed through fat cells?
Didn't we just lose an OAA from the Kreb Cycle? OAA gets combined with Acetyl-co-A to form Citrate, which is moved out of the mitrochondria. How can it cycle, if it loses one of the key components of the cycle?
+Allan Kirk acetyl CoA carboxylase (ACC) is the enzyme that "activates" mitochondrial acetyl CoA so that the acetyl portion is transported into the cytosol in the shape of citrate. ACC is allosterically activated by citrate, and a high mitochondrial concentration of citrate comes from the inactivation of citrate dehydrogenase (TCA). ... So I think that citrate is in excess in the TCA. The cell puts this to good use by committing to fatty acid synthesis (which requires lots of energy, so it makes sense that citrate dehydrogenase is inactivated by high levels of ATP).
There's a cytosolic isoform of malate dehydrogenase that catalyzes the reduction OAA back to malate (the precursor for OAA in the TCA cycle). This malate is then oxidized to pyruvate via an enzyme called malic enzyme (the NADP+ dependent step), releasing a CO2. (Malic enzyme and the PPP are the two sources of NADPH production in our bodies).
Pyruvate Dehydrogenase complex is to produce AcetylCoA. While Pyruvate Carboxylase is to produce Oxaloacetate. Too much AcetylCoA inhibits Pyruvate Dehydrogenase, so that the continuous production of Oxaloacetate through Pyruvate Carboxylase can produce a lot of Oxaloacetate which will combine with the many AcetylCoA to form Citrates so that they can traverse the mitochondrial membrane and proceed with the Fatty acid synthesis. Pyruvate decarboxylase is something else.
you'd better not keep the pen moving without any indication which could bother us, because we are always concentrating on your voice and the pen all the time. anyway the video is still great! thanks!
This comment section is divided between people who absolutely despise her voice and people who are wayyy too seduced by it.... get it together people lmao
I can't get past the first 30 seconds... so when I find that Khan's not doing these videos, I just go back the way I came in. It would be fine if I wasn't so damn sure she's faking it. Stop slurring and get it together woman!
"Jasmine Rana is a MD Candidate at Harvard Medical School, Boston" - you go girl!!!!!
Jaat!!
It should be noted that citrate does not contain acetyl-CoA, but simply acetyl. So the CoA-group is added to the citrate in the cytosol by the means of ATP-citrate lyase after the citrate is transported into the cytosol.
Like, you're right but it's irrelevant and ruins someone's understanding of the pathway. Acetyl-CoA makes citrate, and that's an important part of understanding where citrate comes from and why it is a good regulatory molecule for FA synthesis.
Well acetyl CoA and Oxaloacetate form to make citrate so just a slight difference
I'm always so impressed by your videos. Thanks!
What a GREAT video and explanation! Thank you very much!
Thank you for this video! I am studying for a Metabolic Pathways final exam and this video was very helpful!
Great video, thanks now its so much clearer!
I LOVE her voice!! its so soothing and adorable and for once i didn't feel sleepy and could get through the whole video
This just connected everything together thank you!
It is not pyruvate dehydrogenase but it is pyruvate dehydrogenase complex, because it is made from 3 enzymes subunits.
Very detailed information and well understood. I love your teaching.God bless you.
Great explanation with simplified and enthusiastic way of teaching . Keep it up
awesome lectures. thank you so much. regards, chary
i'm in love with the voice of yours
absolutely amazing.
OMG! Such a perfect video!
this is aesthetic and informative, i love it
Wonderful explanation. Thanks
What really floats my boat is when people use the singular, mitochondrion. Surely mitochondria don't always need to be plural.
amazingly well explained!
Thank you very much indeed ❤
your voice is like a barbie it's so cute
It's perfect! I wish all my professors had this kind of voice.
@@skippythesupercat so that all of them will sound friendly
Very helpful, in deed!
This is tremendously helpful
You're so awesome! Thank you so much. You just summarized everything i've been learning for the past 4 days :)
Helpful , thanks !
Who gives a shit about what her voice sounds like. Don't like it, watch a different one. Thank you for making it easy to understand.
your voice make the lesson understandable
really great, thank you!
Requiring a citrate shuttle in order to get the acetyl-coA from mitochondria out into the cytoplasm seemed like a waste until we realized that once it breaks down to OAA and then to pyruvate, we get NADPH, which is essential to FA synthesis. The cell is such a well oiled machine!
your voice is very special, very baby. very clear explanation. Pls do more. Very helpful to many people in the world
Great lecture
thank you so much
This was so helpful, thanks! I agree with the small already made suggestions of clarifying that citrate doesn't actually contain acetyl-CoA but acetyl itself and also that the pdh is a complexe. also i've never heard of the nadph // oxalacetat --> pyruvat conversion. Instead I was taught that there is an exchange between malat and oxalacetat?
Anyways, those are just minor things - and your voice is not annoying at all! I personally think it's super important for these rather long videos to not be to monotone. Without proper enunciation, which you clearly delivered, it just get's lenghty. Keep it up!
Same i was also taught that it is converted into malate, i'm a little confused on this part
Great explanation :)
thank you!
very well explained
Your voice is so soothing😍
nooo where them subtitles at tho
Since you mentioned that fatty acids can be obtained from the 3 sources, so why does the body still need to make fatty acids?
Thanks .
2:05....post meal.insulin drops and glucagon rises 1-2hours after a meal (thats correct)
BUT glucagon's main effect is on liver not on adipose..Epinephrine and cortisol are the ones that mainly stimulate HSL in adipose(lipolysis) :-)
Thanks for the video Khan Academy
Your voice literally shreds my soul into pieces.
thank you madam ji
Such a cute video
OAA is not converted directly to pyruvate, but first converted to malate which is the converted to pyruvate through malate dehydrogenase, and only in this reaction we earn that nadph you were talking about.
That's why there are 2 arrows between OAA and Pyruvate...
amazingly helpful and a pleasing voice to hear :) thnx a lot !
I know right.. :) the voice is so clear.
It's perfect!! Whoever disliked this video, I got news for you: You're not going to simplify this very complicated topic any better than this already.
Perfect
So when you consume fat from your diet, it eventually gets into your blood stream via chylomicrons. Can the triglycerides be then stored directly as fat in your adipose tissue? Or does it have to first go through glycolysis and turn into Acetyl-CoA and then back to Triglycerides via Fatty Acid Synthesis?
thanks girl
thanks for the awesome videos, I have one question though; what's the enzyme that breaks the citrate into OAA and Acetyl-coA?
+Steve MeMc citrate lyase
lei Alcalde thanks :)
That voice though.. really helpful though girl thanks
i jz hv to be strong, listening to the voice.
whatever man her voice is amazing
I didn't realize that Marcel the Shell knew so much about FA synthesis...
For anyone that doesn't like her voice: change the speed to 1.25. It sounds different.
U must be kidden Idont get any thing her voice was like plapla plaplapla
@@user-kn6eb7qn4v im watching her on ×1.5 and i didnt realize how good her voice was till i read the comments
So fatty acid synthesis is similar to lipid metabolism?
What is the software that they use!?🤔
Heading over to moofuniversity. Better explanation without all the drama.
+RockyCycle :]
Damn! Talk about jilting
She has Khardashian voice.
Thanks for your excellent videos. Can you very kindly clarify the following. Can dietary fat only be burnt by mitochondria if it has first been ‘processed through’ fat cells and released as FFA? Or can mitochondria also burn dietary fat that hasn’t come from a fat cell? Thanks for any comments.
Hi Kyle, you say:
"all Fat will be burned in the mitochondria, however yours is more of a question of Fatty acid transport. Basically your mitochondria will burn fatty acid chains from whatever source they can get them from if the hormone Glucagon is present. whereas if insulin is present it will be stored in adipose. Bear in mind that a small amount of fatty acids will travel around in the blood as part of your VLDL and also attached to Albumin."
You seem to be saying that mitochondria can burn fatty acids even if they have not been released by (come from) fat cells as 'free fatty acids'. Please clarify. My question is simple: apart from glucose, can mitochondria only burn FFA's released by fat cells, or can mitochondria also burn fatty acids that have not been processed through fat cells?
Why is it that when lipogenesis occurs in liver we lack serum-free fatty acids?
❤
should we concentrate on her voice or on FA synthesis :|
I can’t seem to find what type of fat the liver makes from glucose? Saturated?
Wow talk about vocal fryyyyyy!!!! If you speed it up she just sounds like she's got a slight lisp, without the fry :)
the pyrovate molecules convert to AcetylcoA before entering the mitochondria
and thank you it was such a good video
Didn't we just lose an OAA from the Kreb Cycle? OAA gets combined with Acetyl-co-A to form Citrate, which is moved out of the mitrochondria.
How can it cycle, if it loses one of the key components of the cycle?
+Allan Kirk
acetyl CoA carboxylase (ACC) is the enzyme that "activates" mitochondrial acetyl CoA so that the acetyl portion is transported into the cytosol in the shape of citrate.
ACC is allosterically activated by citrate, and a high mitochondrial concentration of citrate comes from the inactivation of citrate dehydrogenase (TCA).
...
So I think that citrate is in excess in the TCA. The cell puts this to good use by committing to fatty acid synthesis (which requires lots of energy, so it makes sense that citrate dehydrogenase is inactivated by high levels of ATP).
That voice omg!
Yo thats an amazing cheeseburger.
If you blink the red part of the capillaries move
It would be so helpful if there was also a transcript that I could read alongside to watching the video
turn subtitles on.
Such a great teacher :) thank you alot ☆☆☆☆☆☆
I thought the reaction of converting pyruvate to OAA is irreversible. How do we make pyruvate from OAA? using a different pathway I reckon?
There's a cytosolic isoform of malate dehydrogenase that catalyzes the reduction OAA back to malate (the precursor for OAA in the TCA cycle). This malate is then oxidized to pyruvate via an enzyme called malic enzyme (the NADP+ dependent step), releasing a CO2. (Malic enzyme and the PPP are the two sources of NADPH production in our bodies).
Where's the dude gone?
is it PyrivateDH or Pyruvate Decarboxylase?
Pyruvate Dehydrogenase complex is to produce AcetylCoA. While Pyruvate Carboxylase is to produce Oxaloacetate. Too much AcetylCoA inhibits Pyruvate Dehydrogenase, so that the continuous production of Oxaloacetate through Pyruvate Carboxylase can produce a lot of Oxaloacetate which will combine with the many AcetylCoA to form Citrates so that they can traverse the mitochondrial membrane and proceed with the Fatty acid synthesis. Pyruvate decarboxylase is something else.
I love how she refers to 'space' as 'realm'. XD
Felia Sunarga she says ‘room’, not realm for space
I was feeling super good about my understanding of these processes, and then she says NADPH and, well... I suppose it's back to studying. :/
I mean.
Huh?
you'd better not keep the pen moving without any indication which could bother us, because we are always concentrating on your voice and the pen all the time. anyway the video is still great! thanks!
I thought glucose is converted into glycerol, where glycerol with fatty acids can form TAGs.
that's the second source of glycerol. (Krebs' cycle)
Thank you so much!! BTW I love your voice! ;)
go to point directly ,it was boooring really more insufficent info
Thanks a lot khan academy this was such a good lecture ! :)
I'm definitely gonna fail out of Biochemistry :S
Hope you passed:) .I'm scared too
@@fatima546 Going through my old comments, and I did pass. I graduated! I hope you passed as well. :)
Thank you but mam little loud voice
I came here to learn about F.A. synthesis not be seduced .___.
Can relate.
What's better than science mixed with seduction? Sapiosexuals approve.
LMAO!
: 3
Ha ha ^.^
Vocal Fry
mumet lur
This comment section is divided between people who absolutely despise her voice and people who are wayyy too seduced by it.... get it together people lmao
lowkey she sounds like ruby from max and ruby
overall its a good video but u r speaking really fast so its difficult for me to get some words..overall nice experience
If you click the options in the corner you can change the playback speed to 0.75 or 0.5 to make it easier to listen to
great job on the video! very well explained.
I really hate how sexist all these stupid comments are
Her voice is interesting.....
I don't think her voice is annoying.
I can't get past the first 30 seconds... so when I find that Khan's not doing these videos, I just go back the way I came in. It would be fine if I wasn't so damn sure she's faking it. Stop slurring and get it together woman!
How can u fake a lisp?
ngomonge kecepeten
The way she pronounces "capillary bed" makes me angry.
So informative but that voice hurts.
someone climaxed at @9:12 for sure.