small part of lecture is wrong, two sister chromatids are exactly same and this is why we consider each centeromere as one chromosome even when it is on the one chromatid strain. In fact, pair chromosomes are 2 different chromosomes (each one has one centromere) that come from two parents.
yes I agree even when he talks about haploid and diploid they have both 2n = 4 and it's wrong ! the diploid cell must have 4 chromosomes while the haploid cell has just 2 chromosomes
7:03 might help as a time stamp, as this is the first time he goes wrong, as far as I can tell. When he points to the left part of the chromosome, that would rather be sister chromatid number 1. When he points to the right half of the chromosome, that is sister chromatid number 2. Both chromatids are identical copies of one another (made during mitosis for instance). These two halves are not however from two different parents.
can you differentiate homologous chromosome and sister chromatid.i think you are calling chromatid as homologous chromosome.may be I m wrong please clear my confusion.otherwise it was really helpfull and I m your big fan.
I wish I could have watched all these videos when I was a Biology major. I bet my GPA would be a 3.4 instead of a 2.9. Your conviction and clarification of these topics are impressive sir!
While your videos are 99.9% awesome and I can never acquire as mich knowledge as you, I believe that you've made a mistake with regards to what a homologous chromosome means and what a diploid and haploid chromosome mean.
Great explanation of the relationship between DNA, Chromatin, and Chromosomes.. I did not realize they were all the same thing - - just different coil levels...
Hello, thanks for your great lectures! At 6:40 you said that one chromosome comes from the mother while the other comes from the father. However it looks like that the representation of the chromosome in the board is a single duplicate chromose with two sister chromatides. Am I right? Is it possibile, naturally, two homologus chromosomes (one from the father and other from the mother) joined by a centromere? Thanks.
Could you please clear up the sister chromatid, chromosome thing? Feel like you got it wrong in the video and have confused a lot of people including me.
During cell division, a chromosome basically replicates its information thus creating two sister chromatids that are conjoined by a centromere. When it comes to chromosomes, in a homologous pair, one comes from the mother while the other one - from the father.
Ur lectures are amazing... I am confused though now. Whenever its in x shape, it should be 2 sister chromatids, meaning its an exact copy ,, meaning its already passed the S stage where each chromatide is copied and then paired using a centromere? Is it!!
Unfortunately some aspects of this lecture are wrong. This channel is still my favorite overall for studying science. Every educational channel I have looked at has an error once in awhile, nobody's perfect.
Sir, I think that the DNA molecule is not wrapped around individual histones(H-2A, H-2B, H-3 and H-4) in a nucleosome. But instead it is wrapped around the core which is made of the above histones.
In a homologous pair of chromosomes, one comes from the mom and the other from the dad. So is each chromosome in the pair made of a different DNA molecule (one from the mom and one from the dad)? Might be a dumb question but I am trying to self-learn genetics as I haven't taken the course yet :/
I had one question, the two chromosomes joined together through the centromere is called homologous chromosomes in this lecture; but in the next lecture (Cell cycle and interphase), you called them sister chromatids. which one is correct? Im very confused, I need answer please....
:eerrrr.... problem (7'10'') a chromosome is all the "X form", not only the half ! The half is a chromatid and the other is a copy of it (the exact copy of the other except in some cases like the crossing over...). One chromosome of the pair is inherited from the father and the other (the over X composed also of two chromatids) is inherited from the mother. Warning.
the depiction of histones and nucleosomes is wrong. A nucleosome is not 8 Histones wrapped with DNA. A Nucleosome is 1 histone wrapped with DNA and a Histone is made up of in total 8 Peptide chains that are called histone molecules!!!
Just watched this video and that chromosome your showing on the left is a single chromosome after replicating it's DNA. Those are sister chromatids connected at the centromere, not two separate chromosomes. Also, the two cells on the right your showing as haploid and diploid have the same number of chromosomes, the only difference is that the cell on the left has replicated it's DNA, thus has completed S phase of the cell cycle, and the cell on the right has not yet replicated it's DNA, thus has not yet entered S phase of the cell cycle. So in the case above both cells on the right have the same number of chromosomes.
i m confused here you said single chromosome is two chromatids each from different parent. isn t the homologous chromosomes that are each from each parent and that a single chromosome is duplicated chromatid from the same parent.?
Yes, you are correct. In each pair of homologous chromosomes, one comes from the mother and the other one - from the father. Chromatids are just a copy of each chromosome that is created and used during cell division.
If I keep thanking God until tomorrow because I found you, it will not be enough ... I prefer not to praise anyone until I make sure that he really deserves it but you always prove yourself worthily, I do not know whether you have a mind in your head or an encyclopedia because I always search for different topics and watch a lot of videos but Surprised that you have explained it too, and in fact, almost these videos Consider as a waste of time in front of your videos,…I am not sure what is the reason that does not make you much more famous!
Question about maternal and paternal chromosomes - in the diagram of the chromosome you pointed out that one was from the maternal and the other from the paternal. I thought that there was two homologous pairs and that the diagram you presented is one of them. I understood that the chromosomes are as you displayed on the whiteboard during replication and the the two parts are the sister chromatids. Could you please explain for me or maybe link me to a video that explains. I am learning about this for my job. Thank you so very much. LA
Sister chromatids are not from different parents..its the 2 chromosomes of the homologous pair that are from different parents and have different genes
I think that chromosomes are counted by number of centromeres. So here we have one chromosome with two chromatids. But you are equating one chromatid with one chromosome. I need clarification
I love biology but I ain't in biology class stuck in physical science its alright but I love DNA and RNA it's fascinating. Now i am planning on a expirement but i only know one. But i want to know another expirement to preform.
Thank you for your great job, I really do appreciate your channel. But I must give reason to some people below: "small part of lecture is wrong, two sister chromatids are exactly same..." @Sina Nouraei Further more the two sister chromatids of one prophase chromosome are the product of the semiconservative Replikation of one DNA Molecule which occurs during the S-Phase of the cell cycle. Do you agree with me? Have you ever consider to change the picture behind you? The "haploid" cell on the right isn't the haploid counterpart of the cell on the left. This cell is diploid - if we consider the two cells of the same exemplary organism - The cell on the right seams much more to be one of the daughter cells of the cell on the left after mitosis. or?
Wow amazing .every time I got confused about any thing in bio chemistry just listen to ur videos that confustion absolutely goes away .may god bless u &award u PROF 😍😍😍
small part of lecture is wrong, two sister chromatids are exactly same and this is why we consider each centeromere as one chromosome even when it is on the one chromatid strain. In fact, pair chromosomes are 2 different chromosomes (each one has one centromere) that come from two parents.
yes I agree even when he talks about haploid and diploid they have both 2n = 4 and it's wrong ! the diploid cell must have 4 chromosomes while the haploid cell has just 2 chromosomes
Actually a diploid cell has 2pairs of each chromosome and a haploid contains only one of the of each chromosomes
Thank you. That perplexed me as I got another information from different sources.
Some portion of lecture is wrong.
7:03 might help as a time stamp, as this is the first time he goes wrong, as far as I can tell.
When he points to the left part of the chromosome, that would rather be sister chromatid number 1. When he points to the right half of the chromosome, that is sister chromatid number 2. Both chromatids are identical copies of one another (made during mitosis for instance). These two halves are not however from two different parents.
can you differentiate homologous chromosome and sister chromatid.i think you are calling chromatid as homologous chromosome.may be I m wrong please clear my confusion.otherwise it was really helpfull and I m your big fan.
DNA doesn't wrap around one histone , it wrap around octamer , isn't it ? Thank you for this helpfull lecture .
Yes you're right
wooooow this guy is crazy clever he also does chem
I wish I could have watched all these videos when I was a Biology major. I bet my GPA would be a 3.4 instead of a 2.9. Your conviction and clarification of these topics are impressive sir!
Obsessed with his accent
While your videos are 99.9% awesome and I can never acquire as mich knowledge as you, I believe that you've made a mistake with regards to what a homologous chromosome means and what a diploid and haploid chromosome mean.
Great explanation of the relationship between DNA, Chromatin, and Chromosomes.. I did not realize they were all the same thing - - just different coil levels...
Hello,
thanks for your great lectures!
At 6:40 you said that one chromosome comes from the mother while the other comes from the father. However it looks like that the representation of the chromosome in the board is a single duplicate chromose with two sister chromatides. Am I right?
Is it possibile, naturally, two homologus chromosomes (one from the father and other from the mother) joined by a centromere?
Thanks.
Could you please clear up the sister chromatid, chromosome thing? Feel like you got it wrong in the video and have confused a lot of people including me.
Exactly
During cell division, a chromosome basically replicates its information thus creating two sister chromatids that are conjoined by a centromere. When it comes to chromosomes, in a homologous pair, one comes from the mother while the other one - from the father.
Yes. It's a pity they didn't corrent it. I started this course and now I am not sure whether to trust it or not.
Marry me
+Jasmine Thorson :-)
Lmao, This is AK's way of saying no politely... Trust me im from NY as well :)... haha
does he ?? hhhhhh ater 2 years of the comment ?
Ur lectures are amazing...
I am confused though now. Whenever its in x shape, it should be 2 sister chromatids, meaning its an exact copy ,, meaning its already passed the S stage where each chromatide is copied and then paired using a centromere? Is it!!
+Mo Faraz yes... thanx Mo
Unfortunately some aspects of this lecture are wrong.
This channel is still my favorite overall for studying science. Every educational channel I have looked at has an error once in awhile, nobody's perfect.
Sir, I think that the DNA molecule is not wrapped around individual histones(H-2A, H-2B, H-3 and H-4) in a nucleosome. But instead it is wrapped around the core which is made of the above histones.
I'm so glad I stumbled upon these videos... Thanks!
In a homologous pair of chromosomes, one comes from the mom and the other from the dad. So is each chromosome in the pair made of a different DNA molecule (one from the mom and one from the dad)? Might be a dumb question but I am trying to self-learn genetics as I haven't taken the course yet :/
yes
I had one question, the two chromosomes joined together through the centromere is called homologous chromosomes in this lecture; but in the next lecture (Cell cycle and interphase), you called them sister chromatids. which one is correct? Im very confused, I need answer please....
No, 2 chromosomes joined together through centromere are not homologous but are sister chromatids
way better than my genetics professor. thank you so much! youre amazing.
:eerrrr.... problem (7'10'') a chromosome is all the "X form", not only the half ! The half is a chromatid and the other is a copy of it (the exact copy of the other except in some cases like the crossing over...). One chromosome of the pair is inherited from the father and the other (the over X composed also of two chromatids) is inherited from the mother. Warning.
Andrey the drawings of diploid and haploid cells are wrong.
Thank you
the depiction of histones and nucleosomes is wrong. A nucleosome is not 8 Histones wrapped with DNA. A Nucleosome is 1 histone wrapped with DNA and a Histone is made up of in total 8 Peptide chains that are called histone molecules!!!
YOU'RE THE G.O.A.T AND THE REASON I UNDERSTAND ANYTHING IN BIO THANK YOU!!!
thanks for sharing us your knowledge... i learned a lots from your videos
Your Videos Really Helps Me A Lot
Thank You
Warning...this lecture has to be corrected!!
Just watched this video and that chromosome your showing on the left is a single chromosome after replicating it's DNA. Those are sister chromatids connected at the centromere, not two separate chromosomes. Also, the two cells on the right your showing as haploid and diploid have the same number of chromosomes, the only difference is that the cell on the left has replicated it's DNA, thus has completed S phase of the cell cycle, and the cell on the right has not yet replicated it's DNA, thus has not yet entered S phase of the cell cycle. So in the case above both cells on the right have the same number of chromosomes.
Aren’t you calling a “chromatid” a chromosome?
Oh my God, I am studying this now in school and I would like to travel to Mars or hope that a meteorite will fall to Earth.
Professor Andrey please could you show me where the genes fit into the picture?
For me UA-cam is ak lecture. Lots and lots of wishes for you Andy. :)
Loving the videos so far , Thank you ! :)
i love ypur manner!! of explain biology!!!
The way he delivered his lectures are amazing..save my biochemistry exams
Do you have a video on polytene chromosomes? :)
i m confused here you said single chromosome is two chromatids each from different parent. isn t the homologous chromosomes that are each from each parent and that a single chromosome is duplicated chromatid from the same parent.?
Yes, you are correct. In each pair of homologous chromosomes, one comes from the mother and the other one - from the father. Chromatids are just a copy of each chromosome that is created and used during cell division.
If I keep thanking God until tomorrow because I found you, it will not be enough ... I prefer not to praise anyone until I make sure that he really deserves it but you always prove yourself worthily, I do not know whether you have a mind in your head or an encyclopedia because I always search for different topics and watch a lot of videos but Surprised that you have explained it too, and in fact, almost these videos Consider as a waste of time in front of your videos,…I am not sure what is the reason that does not make you much more famous!
It's quite Confusing My Knowledge
...sister Chromatids r from 2 different parents ? ?
Question about maternal and paternal chromosomes - in the diagram of the chromosome you pointed out that one was from the maternal and the other from the paternal. I thought that there was two homologous pairs and that the diagram you presented is one of them. I understood that the chromosomes are as you displayed on the whiteboard during replication and the the two parts are the sister chromatids. Could you please explain for me or maybe link me to a video that explains. I am learning about this for my job. Thank you so very much. LA
Sister chromatids are not from different parents..its the 2 chromosomes of the homologous pair that are from different parents and have different genes
I'm so happy for this lectures, thank you sooo much!!!
I think that chromosomes are counted by number of centromeres. So here we have one chromosome with two chromatids. But you are equating one chromatid with one chromosome. I need clarification
Yet again, Andrey to the rescue.
I love biology but I ain't in biology class stuck in physical science its alright but I love DNA and RNA it's fascinating. Now i am planning on a expirement but i only know one. But i want to know another expirement to preform.
Sir,i trust your videos so whenever you make a mistake try to make it right by commenting or explaining the correction in the description.
You’re wrong about histones ... The dna coil around 8 histones not each histone
best teacher i have ever seen
one of my top 2 favorite bio teachers
How do you can explain all the subjects of so many areas? congrats
Sir you're the best teacher, a true science pedagogy. You're lectures are short yet very well explained
Respect & love from India🇮🇳🇮🇳
You are so amazing! Thank you for this, keep doing what you do!!
Why do we need protein to wrap around the double helix DNA molecule and to form centromere?
i have my biology finals today doing a complete marathon or your videos #mylastdaywithbiology.
btw this makes me sad.
I think there is an error in your lecture, centromer binds two chromatid which both of them identical not mix from father and mother
if ii hear basically one more time
I got a question so 1 chromosome contains 2 different DNA molecule ?
@ nidhish gautam.. thanks! but please.. I hate the name andy ... ;-)
+AK LECTURES (Andrey K) Why hate the name Andy? Is adorable...
It was a joke :)
+AK LECTURES (Andrey K) sir did u look at the figure and call the sister chromatids as homologous chromosomes ??
I noticed the same mistake...
there is no any difference between sister chromatids and homologus chromosomes
Thank you for your great job, I really do appreciate your channel.
But I must give reason to some people below: "small part of lecture is wrong, two sister chromatids are exactly same..." @Sina Nouraei Further more the two sister chromatids of one prophase chromosome are the product of the semiconservative Replikation of one DNA Molecule which occurs during the S-Phase of the cell cycle. Do you agree with me?
Have you ever consider to change the picture behind you? The "haploid" cell on the right isn't the haploid counterpart of the cell on the left. This cell is diploid - if we consider the two cells of the same exemplary organism -
The cell on the right seams much more to be one of the daughter cells of the cell on the left after mitosis. or?
why does he call one chromatid of a chromosome an individual chromosome?
I think he is wrong here
#abmebiosciences Chromosome consist of two chromatids
But only during division, right?
Best online Lectures on youtube in my opinion! Keep it up!
Sir you amazing... I'm from Tripura (India)
has increase my dimensions continue ...
Where do Chromatids fit in? Could anyone help me?
Very nice.👌👏👍..thanks sir.
☺☺☺ ...
This guy is a great teacher
Very very very well explained thank you sir
you are of great help for my medicine admission test, some things about miosis just were very hard to understand
amazing videos. thanks a lot sir
-love from india
Why does the chromosome condense during meiosis?
Please tell me about the reference of this vidio
Thanks
You have cleared my doubt tqqq sir
you're the goat
Hell yeah man. You're almost single-handedly getting me through my bio/nursing majors.
Thank you about these information
Brilliant!, I’ve subscribed
n loads of good wishes for you from india
What playlist is that part of? Thank you
Homologous chromosomes≠sister chromatids
you remind me of sheldon copper somehow
you are incredible really thank u u r awsome
Awesome ... learned so much!
Nice
his homologous concept is wrong
Excellent Explanation. Thank you!!
very good explanation (y)
Do u teach in college? ...
Please provide pdf too
Sir your lecture are very helpful
الرجاء الترجمه للعربيه
These lectures are really useful ....thank u..
the GOAT of MCAT prep does it again! haha
You Hero
You're amazing.
Хорошие лекции. Единственно мешает много basically. Извини.
:-) ya soglasen
very clear explanation
in love with your lectures
you saved my semester
Wow amazing .every time I got confused about any thing in bio chemistry just listen to ur videos that confustion absolutely goes away .may god bless u &award u
PROF 😍😍😍
you are very beautiful 😁
thanx
amazing explanation
This videos are helpful. Thanks
+samuel muma you're welcome!