Viruses

[mhmcupcakes]

mmmmmmm virusesssss

[Gmudi]

In pluralis it's ''Vira'' and not ''Viruses.''

[DarkenIsGod]

@Gmudi

No, it's 'viruses'.

[vtattis]

@Gmudi you're soooo wrong. look it up before you make statements. :)

[TheUnchainedMind]

Amazing video, very interesting.

Thank you so much, I will probably be watching a couple of these every day on a multitude of subjects :)

[padlockd]

13:12 poovirus? =P

[TheLegendaryGibbie]

I have a test on viruses tomorrow for my AP Biology class. Thank you so much, this helped me understand viruses a lot more

[WIlmylife]

I have a question:If viruses remain detached from living cells for long periods of time,what happens?Do they just remain there?

[MultiAxian]

@WIlmylife i imagine the protein components would eventually denature and the virus "dies"

[TheUnchainedMind]

@WIlmylife

They are destroyed after a while, at least most viruses are.

If I remember correctly, the HIV virus is especially fragile to the environment, hence why it can only, or almost only, be contracted through bodily fluid exchange.

[swagsism]

"My genes I take very personally!"  haha love these videos!

[ferdlrv]

Exelent! , you help me a lot!! :D

[GollaGandaLova]

Osmosis Jones baby!! lol

[Germaan117]

i think this video was great thanks (: im 15 and i understood it and learnt heeeaps

[Orenotter]

"Interesting" said the disembodied voice of Narnax. "Our scientists and philosophers have long pondered the question of whether cells and the organisms they construct can truly be considered alive."

John raised what he considered an eyebrow. "Ours have puzzled the same question about viruses."

from john Anderson's conversation with an Alkari virus in "The Virus"

[EnigmaHood]

Excellent video!

[iRandomNezzy]

i had homework about this but this guy talks too much >.<

[LittleNinjaWarrior]

endocylosis :)

[xxxdatxxx]

I think this guy knows everything.

[cpmc1]

1) What program are you using for the video?

2) I very much so appreciate you educational videos. I find them quite interesting, and you explain them efficiently.

I have Aspergers and I am "into" Science and Mathematics. I subscribed because your videos is exactly the stuff that I am looking for, education wise.

[sherif529]

how can viruses with ss"single strand"DNA replicate??????

please answer my question if u r sure

[nilorac123321]

@sherif529 Via lytic replication?

[sherif529]

@nilorac123321 thx very much

[ashtongrist]

But do bacteria and thier biproducts play a role in epigenetics and where can II learn about that?

[xqube]

Quoting agent smith. WOAH

[GhostTownLeader]

00:01 look at that dick lol

[GhostTownLeader]

They are like demons. They possess the poor cell :(

[dudecoolname]

KHAN for President 2012

[prangwirong]

thank you very much this is very useful

[vickiormindyb]

The doctor who taught us told us the difference between bacteria, one of them anyway, is that a virus copies information from the cell it attacks by trying to become part of the cell. Bacteria invade the cell differently. They don't try to attach themselves to the cell and take over in the way that a virus does.

[sullivanseven]

I want to give you a criticism khan. Your videos are so lengthy, I guess you don't have to draw and write every thing from scratch and erase them 16 times. be more prepared and make short videos and don't move your cursor so much

[freeskier99]

@sullivanseven What a stupid comment

[aswayb]

@sullivanseven hahaha shutup brah

[deyan1231]

hay u inspired me alot.....i wish i can meet u once in my life

[deyan1231]

hay u inspired me alot.....i wish i can meet u once in my life

[99Argh]

If cell are made of atoms which are non living things, the cells are also non living things and they operate by chemical reactions. Then we are non living thing? im confused

[infinteXetnifni]

so the retro virus changes you into a big, huge virus?

[infinteXetnifni]

if we were viruses we would think humans had no life

[bomberfun1]

Viruses exist until humans exist, they keep populations in balance, otherwise the planet will explode from PEOPLE. Its nature's way to cleanse the planet from humans.

[Nauarattaa]

@bomberfun1 There are actually many different types of viruses for many different types of animals. Viruses aren't specifically designed to kill humans any more then they are designed to kill birds.

[BustaBeet]

u were sick? can't tell by ur voice

[tombafan]

this guys a genius

[GameLover755]

blah blah blah blah XD Nice video tho ;D

[props4peeps]

Retroviruses. . . HOW RUDE!! lol

[ema1171224]

Once viruses are in the body, they are difficult to kill. That is why prevention is so critical. The bloodborne pathogens of primary concern to professional rescuers are the hepatitis B virus, hepatitis C virus and human immunodeficiency virus (HIV).

[papillon2468]

I have an exam tomorrow,

this is a life saver!

[BITTER0N]

Hey man that's the most interesting educational topic I listened too in years.Sweet!!! But can you do an in deep one about HIV cause I still don't understand how the HIV retrovirus kills n decreases t cells,since I read that the t cells reproduce 5 times faster than the HIV retrovirus.So basically that would mean HIV is out gunned drastically.So how our cd4 cells decrease? One more thing I've learned that some people don't have ccr5 in their bodies,so shouldn't this actually be a giant leap tow

[ShevvyTastic]

Brilliant video. Brilliant. :-)

[gemrose12]

I am a sophomore in college at a competitive university studying nursing. I am studying for my final microbiology exam and I came across your videos and website. I think that what you're doing it extremely admirable, not to mention SO HELPFUL. thankyou.

[gemrose12]

I am a sophomore in college at a competitive university studying nursing. I am studying for my final microbiology exam and I came across your videos and website. I think that what you're doing it extremely admirable, not to mention SO HELPFUL. thankyou.

[mill4ever10]

tyvm

[bandgeek551]

Hehe, I have a test on this tomorrow...this video is a great summary of all we've learned about viruses! Thanks!

[josefa1212]

YOUR GAY!!

[awesomeness30000000]

IN KHAN WE TRUST!!!!!!!!

[TheBEATLESMania100]

0.0 thought this was computer viruses

[243734ope]

Thank you

[xxshikki]

I was assigned to report about viruses. I was assigned alone . Good thing i saw this! It helped much! :) thanks~~

[muttamthottil]

hahaha..I luv the way u say 'This is creepy' at 20:00..

Im a proud student of KhanAcademy

[iicox]

How did the first viruses get DNA inside them?

This also means that the question "What is the meaning of life?" must now

be accompanied by the question "What is the meaning of non-life?"

Seriously, why are there packets of DNA just floating around out there?

[busybuzzbuzz]

Viruses blur the boundry between reality and fiction. Not one relevant virus has ever been isolated. "HIV" has never been isolated by Gallo or anyone. Retroviruses were invented when it was discovered that RNA ALWAYS transcribes to DNA. This was a huge embarassement so they conjured up "retroviruses" to cover up for it. Reverse transcriptase is found everywhere in the body that you look for it. The body does not incorporate anything that would interfere with it's homeostatasis. .

[LunchAnderson]

@busybuzzbuzz Piss off, you HIV denialist scumbag.

[1122callie]

AWSOMEE i have an exam tmrw and this stuff is actually helping me

[MsKatie2525]

I'm currently taking a Virology class and it's confusing as heck! This was a good summary of what we've covered so far. THANK YOU!!

[baferdice]

i liked it!!!! :D it helped me out with some lil doubt to explain this subject in easy way...so, TNX!!!!!!!!!! u gr8!

[ArchAngelProducts]

How did I get from Minecraft to this? :S

Anyways, very helpful videos... Love them. ^_^

[runemashta]

To quote Star Trek, "It's life Jim, but not as we know it."

[leprosyliz]

also from 19 onwards the little red thing sitting on the white blood cell looks like a happy little octopus with a virus smiley-face.

You can probably tell i'm a zoology student, we're all a bit simple like that

[leprosyliz]

i think i've been studying for too long and my brain has become fried - but I couldn't stop giggling when you wrote up "poovirus"

[BOBandBILLrock]

@leprosyliz i' m such a dork, i laughed too

[Adamus70]

@BOBandBILLrock Fight against Cancer or AIDS with the help of your personal computer?

And use the Computer just as before at the same time?

Not possible?

Possible.

Give worldcommunitygrid in Youtube search field or any search machine. Installing BOINC is safe and for free.

The Programm runs without problems for years already.

Thanks, in the name of severly ill people, for your attention.

Please do not only watch videos, make the world a more beautiful place helping ill people with your PC

[Roshid2008]

Very helpful, thank you sal!

[TheDodgersAreTrash]

Viruses = amazing at trolling

[TheDodgersAreTrash]

"Every mammal on this planet instinctively develops a natural equilibrium with its surrounding environment, but you humans do not. You move to an area and you multiply, and multiply until every natural resource is consumed. The only way you can survive is to spread to another area. There is another organism on this planet that follows the same pattern. Do you know what it is? A virus. Human beings are a disease, a cancer of this planet. You are a plague, and we... are the cure." - Agent Smith

[Drsandshark]

@TheDodgersAreTrash The only problem with that is viruses are classified as biotic, we are biotic. We grow, we change we adapt, viruses do not. Suck it Smith.

[averinhotmailcom]

@TheDodgersAreTrash just as the viruses have made themselves part of us we have made ourselves part of the earth we have affected just by succeeding in life as does any organism if you say you love earth your saying you love humans because we've made it the way it is and you what i like it this way and it could stand to be a little warmer polar bears can swim so fuck u and fuck ur mom

[vietkrazygyrl]

thank you soo much, this was really really helpful!

[iamipula]

what program is this you're writing in?

[annakareninarose]

thank you!!!!!!!!!!!

[brucemurraywills]

Sal, these vids are fantastic I use them for all my exams. Just wondering where you get one of those black screens with the diff colours from? would love to use one just to practice my exam stuff on. Thanks

[rktguy]

@brucemurraywills dude its just paint. every windows computer has it

[whisper012]

@rktguy No it's not just paint, paint is nothing like this. If you watch his CBS video you can see the pad that he uses with I imagine some sort of wonderful software program.

[rktguy]

@whisper012 this dudes on cbs??

[whisper012]

@rktguy apologies, it was PBS search "Kahn academy on PBS" should find a short clip of a segment that PBS did on his work

[rktguy]

@whisper012 oh ok lol. k thanks ill look into it

[yoyofargo]

When we have our at-home-replication printers, (think reprap) I can see viruses becoming an issue. Little robots/viruses/rootkits that embed code into the item-to-be-printed's code will produce little spy-bots that will invade all of our privacy... P-_-

[floopy312]

@khanacademy I think viruses are alive because even when they don't move or do something. Think of those animals and insects that "HIBERNATE" and dont't move for months but then all of a sudden they come back to live again and start moving again... so is the same thing as viruses. They do have life but they're just hibernating most of the time.

[Lonely401]

@floopy312 virus aint alive until they get a host to take over

[mstodaker]

@floopy312 Viruses aren't living organisms. They don't grow and develop, they don't reproduce on their own, they don't do many things. It's only when they get host cells do they "reproduce."

[Greenwood007]

Well done

[Judicial78]

Life itself is the coding in DNA, much like a program in a computer is binary code. The computer or the body is the shell that carries it. The code in DNA can produce anything possible in biological terms and thus if the way a virus works is effective biologically in our ecological system (earth) it is to be expected to be encountered. Biology can be as complex as an entire body, or as simple as a virus. Its all about the coding.

[TeddCIII]

Hey Sal,

Make a MCAT playlist! You are a great teacher.

[josefgiven]

I've watched all of Sal's biology vids so far. This is by far the most mind-blowing. So 5-8% of me is freeloading viral DNA? Get it out! OUT!

[dalcde]

It's weird. At the beginning when Sal asked whether viruses are living, I couldn't quite decide. During the video, when I am digesting the information, I think viruses as living things that could do a lot of different things, since they do a lot of fascinating things.

[zZTheEvilTeddyBearZz]

omg ur good at writing on cp or pc i forgot lol but yea... O.O

[Ravoliable]

could you make a video on immune and levels of defence in our body like three levels of defences..and information related to all that..........

[Tonyhack1]

Do you have a video of junior biology. I'm starting 10th grade in a couple of weeks.

[cazzist]

wow!!!

[jontan7]

As an engineer studying for the MCAT (with little college level bio), I'm very thankful for your videos! They're a great way to understand the big picture. Keep it up! :)

[Tonty53]

Complimenti veramente istruttivo.

BRAVO !!

[montenegrin2010]

WHY DO THEY EXIST????

[hackster360]

this guy must have one s-levels or something

[EthioOz]

Thanks sir. you explained it in a very fantastic way!

[MrBipBipp]

Could all complex life be machines whose only purpose is to replicate DNA? That sure is an inspiring meaning of life... However, it must be true. If we look at irrational animals, who are not capable of "disobeying" their instincts, we can see that all they do is eat and dominate both the environment and other species (preserve the DNA), and reproduce (replicate the DNA). They are merely DNA's tools. How can we be sure that humans are not the same?

[Rigelcentauri58]

Congratulations!! You have a great capacity to transmit knowledge. Also your diction is very good, and for us, english-as-a-second-language people the way you speak is completely understandable. Gracias amigo.

[isastruve]

greattt

[qwertyboy1234567899]

this sounds like collin cunningham from make magazine

[oehieze]

Lame and Boring

[85beautifulbutterfly]

Thanks this will help me so much for my test = )

[CaptainFluffy6644]

sal:

MY GENES, I TAKE VERY PERSONALLY

[MRincorperated]

were all being used by viruses to get around like big cars

[tenshi789]

very very helpful thank you so much!

[lacasini]

Viruses creep me out. They have no reason exist other than living in people and making them sick. At least bacteria are trying to survive.

[jabiv25]

Damn, Sal! That is so cool. I always suspected that evolution wasn't so vertical. Thanks for giving us some facts on the this fascinating phenomenon.

[XHUMBITO1]

thanx a lot.

[DrJr7]

thaaaaanx alot

this is very useful for me and I think for all

[pamauz91]

This is going to be really helpful for my background info for my poster assignment dued in 2 weeks on herpes.

Thanks. :)

[lyingstudent]

Biology in education is by far the most boring science subject, however your video and explanations are incredibly interesting

[CuppaS00p]

Viruses are probably the most interesting subject in biology, which is probably why.

[monstermac77]

Fantastic, your videos will act as a valuable resource to me now. Thank You.

[Lawless7777]

nice video thanks man!

[ebonyamberjade]

Another excellent video

[xenoepist]

Are you a college teacher? If not, you should be! Your explanations are awesome, a 10 minute video is more informative than a 2 hour lecture.

[YersiniaPestisNPO]

Sal your the man.

[brianberes]

Bravo! Excellent explanation of viruses. It helped me tremendously and you explained it better than my instructor.

[crucialconflict02]

very useful and informative. thanks alot.

[Jakez98]

Now they should make a horror film about viruses!

[Hockey14scorer]

God. This is amazing. It's as if your right next to me telling me what the teacher is telling the class, but what I don't understand.

Thank you so much.

[StrawberriHearts]

your writing is getting nicer and more legible by each video

lol

[angelinghaven]

haha. this guy actually makes me laugh during his lectures. :)

[eillz01]

Great vid, this'll help with my Biology exams coming up :)

[meemz05]

great video! :)

[XxShiaAfghanxX]

very good Sal

[ad2181]

Sal,

This is spooky stuff.

I 'm going to dress up as a virus for halloween.

[landovida]

Wow! I thought about the same thing! :D

[SilenceBeGolden]

Viruses are the featured article on Wikipedia today.

o.O

[Ormaaj]

IIRC horizontal gene transfer refers to plasmids swapping between and integrating themselves into the genomes of single-celled organisms. Its horizontal because it affects the genome of the entire organism between reproductive iterations.

Its hard to do that in a multi-celled organism because you need to affect a lot of cells, hence the difficulty in gene therapy. Also in order for the changes to propagate, it must affect gametes rather than somatic cells, and isn't technically horizontal.

[pongman]

Tamiflu. Sal ask your wife to get you a package.

[Mercuriousss]

Good video. If anyone is interested in learning more about Endrogenous Retroviruses (ERV's) just google "ERV". One of the top results will be a blog on Scienceblogs (dot) com. Abbie Smith, the blogger, is a HIV researcher at the Univ of Oklahoma. She is a great read, and able to communicate her knowledge in a very easily understood way.

[MSI2k]

5-8% eh? Well it must've been beneficial for us as Humans, since any adverse diversification would've had that particular pool be discarded.

[rinwhr]

Wow the words are more readable now lol

[ChewyWiener]

oooo . . . scary.

Just in time for Halloween!

[Academicsandmusic]

I wonder if we were viruses once?

[CreepNarrator]

we were not

[Academicsandmusic]

Well, that's a very elaborate answer. I mean what If all life came from viruses, and evolution picked out the ones who could think?

[CreepNarrator]

The fact that you don't see how what you're saying doesn't make sense, means you need to research what you are trying to talk about more. I mean I don't really know how to answer what you are saying because it's kinda asinine.

[Academicsandmusic]

The fact that I'm only 16 and live in the free-world might explain why I would like to learn something I might not quite know. You on the other-hand do not have the right to called me "asinine", which I do take into offence!

[Academicsandmusic]

Maybe because of this I will prove you wrong or die trying. Which is probably more of a significance of what you're capable of achieving from what I've had observed from your attitude, work-ethic, and a strong distaste of someone you don't know a thing about. To conclude, I won't sink to your level by calling a person a name. So, I will give you this quote: "A rose by any other name is just as sweet."- I hoped you learned something!

[CreepNarrator]

I didn't call you asinine I said the premise behind the idea you presented was. And thats why I can't give a more coherent answer other than We weren't viruses. Its hard to explain why this is true, and would take longer than I have. I also didn't mean to offend. I'm sure your question can be answered if you watch this entire playlist all the way through because this is the last video in this playlist and thus more complicated. if you start here it can get confusing.

[GetModernWarfare]

Yeah ur right khan they are fascinating

[CogitoErgoCogitoSum]

I found your bit on proviruses quite interesting, and entirely new to me. 5-8%, you say? Im wondering how these viruses continue to spread their kind? To they manufacture copies of themselves in your cells? If so, they would have to release those copies without killing the host. Or are they content with just incorporation into another being, to carry on as a part of the host species?

[iydsysstole101]

Why not make a virus and than inject it in the heart which reproduces tissue? Through stamcell, or is that not possible hhaha?

[StevenZB1]

Well, stem-cell researchers are trying to achieve just that. Unfortunately they are running into many obstacles because of the law.

[idricool]

People if you don't know anything about biology or if you're not asking any questions don't comment please.

[afdhalatifftan92]

Eeerr, I believe it's wont hurt to ask, right?

[Chitownboy1023]

Are you implying that god is a virus and that the real party is down at the molecular level?

[blackdranfire]

Maybe you can do one on Swine Flu

[WhosAlex]

He said orgasm.

[WhosAlex]

IT JUST

FUCKING

SITS THERE.

[irmb5teS]

viruses are thinking for themselves :/

[GDATERRY]

Also, at the ending you should have mentioned how Viruses can cause cancer. I'm not too sure about it, but I'm guessing their insertion of genetic material can damage yours?

[GDATERRY]

Khan, at this rate you'll really, really need to make a more organized layout for your site. O.O It's just hard to find stuff.

Love the video, keep doing what you're doing.

[Riverdale270]

everybody has a cold this weekend... its creepy :P

[clerlic]

While viruses use humans to replicate themselves, humans are beginning to use viruses for awesome things like nanotechnology. Which will assist in the battle against viruses.

[IIKruZerII]

Get well from your cold!

[ClintfromNYtoVA]

very fascinating stuff. can you show recombinomics and how it occurs.

The more people know about this the better.

[boratilike]

please continue to make more

[Palaflax]

lol pacman at 9:04

awesome video as always Sal, keep up the good work!

[alique087]

Birdflu

[ViraIVideos]

I agree with you, They are the most fascinated things :)

I'm working to become a Virologist.

[GetModernWarfare]

Why??

[khanacademy]

Probably because they're fascinating :)

[xraidedlok]

@GetModernWarfare shut up go play your modern warfare you brain washed child