Mitosis, Meiosis and Sexual Reproduction

[@w.k7866]

Your are God's gift to BIO students

[@kristinakaraivanova1705]

COVERUР ЕХРОSЕD: ЕD wаs сurеd 300 уеаrs BЕFОRE Viаgrаааа => twitter.com/69d21b393ddb1d94e/status/804602507225808896 Мitosis Меiоsis and Sехuаl Rеprоооduсtiоn

[@crystalheresy7812]

LOL my high school biology teacher is really bad so I've had to watch Khan Academy to learn the entire course.

[@nicholasalexander4621]

It’s okay our school system is only built around money and not teaching people what they need to know. Glad to see another critical thinker

[@llll-lk2mm]

@@nicholasalexander4621 same here!

[@rebelgurl182008]

You made my night. You are more interesting and informative than my bio professor.. I learned more from you and did not fall asleep. I love bright colorful pictures. Thanks a bunch.

[@Appledog01]

Thankyou so much for the video. Great explanation❤️

[@cococure3392]

Awesome video.

[@Luvisill]

Here am I after 12 years.

[@strawssurfer13]

How the hell could you dislike this?

[@kipling1957]

This is a why question, which I know scientists hate. But why is meiosis configured to produce 4 gametes? What is the evolutionary predicate? For example, if the germ cell was to forego DNA replication, not produce sister chromatids, but simply divide up the paternal and maternal chromosomes into two cells, your could still have 2 haploid gametes. So, why did the process evolve the way it did? I'm not asking for wild uninformed speculation. But surely some prominent evolutionary biologists must have considered this question over previous decades and come up with feasible scenarios? I just can't seem to find anything out there. Lots of "whats" and no "whys" - which is kind of boring. Show less

[@ACB487]

kipling1957 Look into crossing over that occurs in prophase 1 of meiosis. This essentially mixes up the chromosomes from your mother and father, which helps to further increase genetic diversity. These mixed sister chromatids are then randomly assorted into each of 4 haploid cells. Look up crossing-over and Holliday junctions.

[@suptigupta9113]

cn u give d whole explaination of the full chapter?

[@soupinacup]

why is he talking about society and predators i just wanna finish my homework

[@yazlinne50]

Is this guy a genius? He knows every subject there is to know!

[@daivdninjabiomech7888]

no, he just reads books right before doing the lessons.

[@brettbrzycki6845]

Bye books you mean Wikipedia, right? @@daivdninjabiomech7888 ?

[@daivdninjabiomech7888]

@@brettbrzycki6845 wikipedia sucks for learning things

[@brettbrzycki6845]

@@daivdninjabiomech7888 yeah but he uses it... He even says it himself in another video

[@reezis1619]

+Brett Brzycki I seriously doubt he uses Wikipedia, in order to explain a subject as good as khan academy does you have to understand a subject profoundly yourself. His videos are so simplified even a 6 year old can understand any subject from advanced physics to biology. He takes abstract formulas / processes in physics, biology, chemistry and explains it so anyone can understand through relating the topics to every-day life things and to the foundation of the topic itself. For example, back in high school I watched his videos on circuits and he explained how every single electron interacted and how it lead to the formula Ohms Law, he even related the electrons in a circuit to water flowing and he used analogies that made it so easy to understand. My teacher just explained the formula abstractly without explaining why the formula is U=I*R. He is an insanely intelligent man, don't discredit his accomplishment by saying he copy pastes Wikipedia.

[@eliudtejada9867]

Who else thought his drawing of the human being was splendid? Cause I did.

[@tanyachong2801]

+eliud tejada Me! I was thinking the same and came into the comments to see if anyone else did:)

[@eliudtejada9867]

LOL great minds think alike! Tanya Morales

[@pranabsaha683]

Really good 😳😳

[@amberriley7633]

When science finally makes sense Khan Academy Thank you so much, I never thought I would ever be able to understand this but now i feel ready for my exam.

[@senthilkarpagam4460]

My textbooks made no sense for some 7 long months and here goes a 20 minute video explaining almost more than what I wanted!! Kudos to you man

[@katali4122]

I learned more in these 18 minutes than I did in my biology class all semester. Mitosis, meiosis test tomorrow and this should definitely help. Thank you!

[@savethestick8609]

8 years later and i’m in the exact same situation 😂 this stuff will never get old, this guys is gonna live forever through these videos

[@ryn006]

wow..total "aha moment" for me. after i don't know how many times this was taught to me, it actually makes sense now. its the same information, but the way that you explain it....bravo, good sir, bravo.

[@fatgoaly]

i love it, but im ocd about how if you just did two more chromosomes from your mother you would've have all 23... just TWO more chromosomes!

[@esjcollins]

Great video. Nice positioning of the 'arrow' on the human!

[@MS-zr8wj]

Haha

[@sball95]

My mom, a doctor from back home, was amazed at how clearly Sal explained the concepts of mitosis and meiosis. Keep up the good work Sal!

[@emon3851]

Wow

[@ChiragSonne]

@@emon3851 wow

[@michaelsaez7162]

@@ChiragSonne wow

[@alyaziahamadalaryani7409]

@@michaelsaez7162wow😂

[@ashamccall3821]

I want to know how he learned all this...

[@MonokumasSlave]

Sperm cells basically does this battle royale for the egg. remember, you were the one who got the victory royale.

[@CaptainUrielVentris7]

One problem I found, the first sperm does not usually fertilise the egg, the first often tires and dies (not quite so inspiring I know). The cumulus oophorus surrounding the egg requires the efforts of many sperm for one to penetrate. So in reality rather than the sprinter we are actually the sperm who finished the marathon and through using others nabbed the ultimate prize.

[@Livinglifehigh]

please please dont delete these biology videos! and please make more of them!

[@karlabingol5314]

14 years wow

[@Swift326x]

Z he still alive 🥺​@@karlabingol5314

[@TheAfricancats]

its easy but my teacher just makes it seem so darn difficult but hopefully this will help me pass my test tommorow. fingers crossed

[@henrygreaves8983]

how’d u go

[@FlowerOFpeace1]

It's amazing!! just we have to imagine how our god (Allah) is great, we were just one cell in our mothers womb!! then we became a full human with millions of cells and a complex organs systems !! just say "SUBHAN ALLAH" , the GOD who created us is very great, so we have to be MUSLIMS and obey ALLAH and worship him as he want. Because the creature should obey his creator. thank you for those benefits videos.

[@dxStevenS]

No, you can't. It's always one egg and one sperm. Fraternal twins come about by having the egg split into two, and having two sperms fertilize them (therefore they are not identical). Identical twins arise from one fertilize egg (or zygote) that for some reason splits in half, which then both develop into two identical twins.

[@radhhpatel]

thank you, a day before final exam!

[@Linda-oc7ve]

That “I believe I am a human” didn’t sound too convincing Sal

[@WantedBabe95]

wow I actually understand this, I think I'm going to cry.

[@witcher4769]

Hello, thanks for your videos helps a lot. It might be a stupid question, but why cant life start with just 23 chromosomes, what is the reason for having diploid number of chromosomes, since each homologous pair have similar genes that can code for a protein. So why cant an egg cell just start to divide?

[@madkatt333]

Witcher47 I am not an expert but from my knowledge some species do and our cells continuously decide our body to replace old ones (think dead skin). We just reproduce needed both.

[@tannerhanks5353]

unless u want ur kids to look exactly like you hahaha

[@sday813]

EVERYTHING MAKES SENSE NOW

[@kareehudock34]

I seriously learned more in this 18 minutes then my last 7 weeks in class.. Thank you!!!

[@jagadishpatil823]

very useful no need of classes

[@XxAlessiaxX1]

exam tomorrow:((((

[@bknisha120]

started from a zaygote now im here!!!!

[@NOKUT0]

wheres the battlefield videos im lost

[@NextGenAge]

I haven't had biology in highschool and this is so useful for my intro courses on the university. Thanks alot!

[@joekeaveny4459]

thank you very much for teaching more about biology in a few hours than my teacher in 4 months!!!!!!!!!!!

[@khanacademy]

If they are not in a germ cell, how do they end up in the DNA of the offspring?

[@ChiragSonne]

Cool

[@DimondAtlas]

People here 80% People that have a test tomorrow 15% People that are doing homework 5% people who are interested

[@jenc9653]

😂😂😂

[@Ree_Spec]

@HigherPlanes Yeah but by that logic, so were they.

[@Swetlana0]

I suddenly started to like Biology Wow keep up the good work Sal!!!

[@cosmagramma]

i learned more from this than from 4 biology lessons, thank you

[@dr.paddlesmack2054]

holy cow, this is inspiring how well u teach

[@ixlandb]

Can I just say that I love you? I hate biology!! But you make it easy to understand!

[@nauleh8006]

watch me still fail this bio tedt

[@marcadams440]

I was under the impression that gender is a social construct and sex is non binary.

[@baguettegott3409]

And that is true, but they're apparently simplifying stuff here.

[@marcadams440]

@@baguettegott3409 Biologists love to simplify biology. Idiots

[@alauc]

God blessed you, dear Sal Khan

[@foziarani1531]

Great awesome video,,, i swear no one could explain it like you,,,

[@95TurboSol]

13:08 the arrow LOL, it is a black guy though! Sorry I couldn't resist.

[@weirdzfully]

They turned into your amazinng brain

[@danielterburg6881]

I got a question. How can hereditary diseases be passed over to your child without mutations? Like for example, autism is a hereditary disease, but it's still caused by mutations, right?? Then how does that work?

[@baguettegott3409]

0:46 I hate to be THAT person, but it'd be cool if you said "sex" there instead of "gender", since it's chromosomal sex that you're discussing.

[@kawsexpo281]

The capable shield happily film because garage naturalistically walk aboard a observant william. voracious, fanatical french

[@YBenjamin1996]

people say that the internet is harmful andthat it damages young peoples minds. This proves all those people wrong. Thank you.

[@edensavril1082]

Hi, you talked about 280 millions sperm in competition and 4 daughter cells. What do they have to see in common and the differences?

[@SamanthaBrown2010]

Thank you for making this amazing video. I learned a lot more this video than what my Bio teacher is teaching me .

[@chocho153]

your mother looks very nice =]

[@542pixie1]

omg thankyou :) this is so mindfucking in my book

[@carminecancro3488]

pov day before test

[@ainsalleh]

8:11 the r r r hahaa this is funny. Anyway thanks a lot!!! It helps

[@ibikimorino2415]

I am definitely gonna bring 💯 on tomorrow's test

[@brainwise8592]

Sir,it would be very kind of you , if you answer to a question of mine.Are the 4sperms or male gametes formed are in a race of fertile the female gametes or ova

[@wholovessongs1596]

I don't understand in school because of the kids but in this video I just understood every everything thank you so much

[@TheRebekah1967]

Thanks so much! This has helped me prepare for a test.

[@rayan2620]

I’m in grade 7 and I’m taking this help me I understand mitosis but barely understand meosis

[@OpenComments]

"Approximately 1 1/2 years before I left, a new rule came out stating that if you got pregnant, you had to either get an abortion, which was heavily pushed, or leave. The rule had previously been that if you got pregnant, you had to get an abortion or be sent to a small and failing lower organization where you had to fend for yourself and your baby." - Declaration of Astra Woodcraft, ex-scientologist, former Sea Org member, and owner of exscientologykids(.)com, 24 January 2001.

[@zguitarmaster]

Why isn't this video on the official Khan Academy page anymore?

[@NeutralExistence]

Couldn't mutations in your body effect the way your germ cells/gametes are produced? For example a mutation of the liver, which causes it to no longer detoxify, wouldn't that end up effecting the gamete production, and possibly leading to hereditary damage? Seems like its illogical to state that there is no way it could effect your children, if one has mutations of the body, they usually effect the whole system.

[@ABooleanEarth]

Germ cells are not somatic cells in that sense. So, if a mutation affects your germ cells or is the result of underlying genes in all your cells, then it will be passed on. If, however, radiation or a fault of genetic reproduction during mitosis or something causes a local mutation in your somatic cells that aren't the ones that will produce reproductive cells, the mutation won't be passed on. Does that make sense?

[@Greensky02]

@TheJohannamurray Kornkornkorn (brilliant username by the way...) started off by saying that he believes in science but not in Natural Selection or Evolution. You can't selectively agree with one aspect of proven fact and not another. That's called denial. So yes, I do get heated when it comes to plain stupidity. I have no problem with religions as a whole. Go on and believe whatever you want to believe, as long as it's not hurting society. Telling everyone that evolution is silly, harms society

[@rjay0195]

@jeanpeup There can be a link, but it is complex and difficult to generalize about. There are many genes, and not all are equally important at all times. Life as a sperm cell and life as a human being are quite different. The gene complement that make a sperm swim fast or an egg viable may are not necessarily related to the gene complement that would make you develop normally versus a trisomic complement, or some other pathological/syndrome. In this case genes for sperm speed are selected for.

[@jeanpeup]

Can the 'sperm cells race' can really be assimilated to natural selection ? What is the link between the sperm cell 'speed' and the 'quality' of the chromosomes that are inside ? I don't think there is a link at all, I think down syndrome or other chromosomal condition would not exist is ther were a link. I'm a noob in biology but this part of sal's speech bother me, can someone enlighten me ?

[@Greensky02]

@TheKornkornkorn You don't have to love all mankind just because someone told you that you should. Some people truly are just assholes.You don't believe in being good for Santa Clause so that you'll get presents from him when the time comes, do you? Of course not. Because that's just silly. In this case getting into "heaven" is like expecting presents for being a good person.

[@jamesusespivot]

@Brendand0n in which case weird will be wiped out however, sometimes weired is good, then it will be encourage and cherised until it is no longer weird, how else did we come about, we are very "weird" compared to other animals.

[@Pinkpenguin1013]

What the hell is your problem? This is a video for learning, not for criticizing other people. You have no idea who I am. Why are you picking on me? Do you have nothing better to do then sit at home and get off on being mean to other people for no reason whatsoever...

[@BigMacForce]

except technically it did not have to be the first spermatocyte to the egg because it takes hundreds of sperm's enzymes (stored in the acrosome or head of the sperm) in order to breakdown the outter layer of the ovum. so instead of the fastest, it is the smartest sperm

[@callummacfarlane]

While TheInvalidInput is correct, Cancer requires multiple mutations in your genes for the cells to become cancerous. So you can inherit mutated genes that predispose you to cancer but in the end these inherited genetic mutations require additional mutations for the cell to become cancerous.

[@DimondAtlas]

Excuse me...I don't mean to but in...but you've lost the argument....every comment u put has been hidden due to negative reviews...his has not, as well as 2 of his comments have been top comment so I think I speak for everyone when I say: Go away :)

[@evilslig]

So the sperm and egg cells consist of 23 chromosomes: 22 individual chromosomes plus 1 X or Y chromosome, but since the X and Y chromosomes consist of two chromosomes joined by a centremer - isn't that technically 24 chromosomes?

[@pumbus1]

no cancer cells THAT I KNOW OF, but there are some cells that are known to cause cancer or to be present in people with certain types of cancers that can be passed on, for types of ovarian cancer i think , if that makes any sense

[@phoneylala90]

@cockywatchman1976 You shouldn't classify holy texts as novels. I'm not a Christian and I think what he said is absolutely ignorant. I just think that a real religion has the truth. Natural selection isn't something you choose to believe or not.

[@guitarzilla]

well I suppose that would be correct assuming that said mutation would impair mobility or the ability for it to fertilize. I think that is what some of the explanation was about though and that is why I was lead to the conclusion I made.

[@Pinkpenguin1013]

Excuse me? I am not a loser. In fact, I do know that half of my genetic material came from my mother. Let me clarify it for you then.. the haploid I received from my father made me a winner.

[@Constans69able]

@LalalusciousMacy18 i actually bough a book but my professor doesn't teach shit and you need a dictionary to understand the book. This is so much better, I'm no longer freaking out over biology class.

[@guitarzilla]

sure, more cells, more chance of a mutation, but if the genetic aberration is carried by the female chromosomes, then the likely hood would be greater in the female.

[@foziarani1531]

Live long

[@Greensky02]

@TheKornkornkorn Oh wow! You must have heard something convincing enough to ignore scientific facts! What is it? A new study? I would be curious to know!

[@ZehMagster]

If your mutation doesn't affect what you pass on to your children. Then what's genetics for? I have scoliosis. My doctor says that it was from my father

[@RMLLcrazy]

Sure as hell this is more than obvious... And its over explained. You repeted yourself more than 50 times. It just annoyed the hell out of me.

[@Greensky02]

@TheKornkornkorn Well, in the future, for your sake, I hope you also love using your mind and questioning things. Even just a little bit!

[@horse433]

The sperm race to the egg was your battle royal win. Congrats

[@naveedlalkhan]

@khanacademy, i heard that X and Y fusion = male boys on and X X = female daughter? and does masturbation effect sperm count?

[@MercurialSwerve]

i started watching this video thinking im going to fuck up my bio test tomorrow but god damnet this shit seems so easy thanks to you

[@kreme341]

wtf man, why would you comment in the first place for a pretty obvious statement and then go on about how stupid THEY are? beats me

[@werewolf7789]

when he drew the little person after the cell splitting at 11: 43 it kinda reminds me of a super badass maniac from BORDERLANDS2.

[@Ibahz]

I wonder if a malfunction in the sperm machinery would be correlated with a visible human mutation (down's, cri du chat, etc....)

[@GokuHyperbeam69]

6:14 "...these are both EGGS-amples..."

[@jpatrone98]

thanks so much i been doing good with mitois,meiosis and sexual reproduction thanks to this video thanks you help me alot.

[@pareku]

i have a question about the "passing on". Is there any type of cancer that could be passed on genetically through family?