MEIOSIS explained in Tamil | Reduction division
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MEIOSIS explained in Tamil | Reduction division

Hi friends In this video we are going to see about meiosis Please don’t confuse it with mitosis Both are different processes Let me give a small overview about mitosis and then we will see meiosis Mitosis is the normal cell division that takes place in our body During mitosis one cell divide into two cell These two cells will looks exactly identical to each other Every human cell has 46 chromosomes for example skin cells,liver cells,muscle cells Mitosis takes place in all of these cells When mitosis takes place Two cells are produced Both have same number of chromosomes ie)46 These cells will be exactly same Please watch our Mitosis video for more information Now lets get into Meiosis I had already said that all of our cells has 46 chromosomes But there is a small change in that statement Male sperms and female eggs have only 23 chromosomes So that during reproduction 23 chromosomes from male and 23 chromosome from female combines to form a cell which we call ZYGOTE which has 46 chromosome This cell that has 46 chromosomes starts developing into a baby Then this baby develops into a full sized human Every cell on this human has 46 chromosomes but the sperm which he produces has 23 chromosomes whether it is a sperm nor egg which carry only 23 chromosomes both of them has to be developed from a normal cell which carry 46 chromosomes It looks simple right cells that carry 46 chromosomes split into two cells each with 23 chromosomes but the trick here is, there are actually four cells produced each carry 23 chromosomes So in Male there are four sperms produced from a single cell In female four eggs are produced As the cells goes from 46 to 23 during this division It is called as Reduction Division Did you ever had this question How a children born to same parents looks different The answer for all of these is Meiosis Our cells has 46 chromosomes It is found on our cells as 23 pairs Just look at this pair One of the chromosome of this pair may be came from a father another chromosome will came from mother In this pair this may be came from mother this may be came from the father So 23 chromosomes came from father and 23 chromosomes came from mother So there will be 46 chromosomes in total These two chromosomes looks identical These two chromosomes looks identical which means two chromosomes in every pair is identical to each other so it is called homologous chromosomes but when we compare one pair with another pair there will be a difference is size,structure and sequence I think you got an idea about the chromosomal pair now the cell that carry this chromosome is going to divide whether it is mitosis or meiosis there should be DNA replication takes place before the cell has to be divide now this chromosome has one DNA strand in it DNA replication takes place and a new strand is produced, so an another chromosome Both of these chromosomes will be joined like this It is a single chromosome only but there are two chromatids. It is same to all other chromosomes So in a cell that has 46 chromosomes, DNA replication takes place and it forms 46 chromosomes but 92 chromatids please watch our video on chromosomes for more detailed explanation Both Mitosis and Meiosis has same four steps they are Prophase, Metaphase, Anaphase, Telophase but in meiosis
this four steps takes place once again so we name the first cycle in meiosis as prophase | metaphase | Anaphase | Telophase | and the second cycle is called Prophase ||, metaphase ||,Anaphase ||,Telophase || I am going to focus only four chromosome in a cell where meiosis takes place but it is same to all other chromosomes As we taught earlier DNA replication takes place and two two chromatids are produced on each chromosome In prophase | chromosomes starts thickening before entering into the meiosis DNA will look like this it is uncoiled During Prophase | this uncoiled DNA tightens and comes to the chromosome structure also nuclear membrane disappeared during prophase | then the homologous chromosomes starts meeting each other when they meet each other there is a process called crossing over takes place During crossing over, segments in the chromosomes starts exchanging between each other reason for the crossing over will be discussed later. Now the next step Metaphase | During Metaphase | chromosomes align in the middle in two lines one line has 23 chromosomes and the other line 23 chromosomes during all of these process the organelle called centromere starts moving towards the two ends while it is moving it organize a structure called spindle fibers like this When the metaphase | finishes both of these centrosomes will be at the both ends and the spindle fibres from the centrosomes joined with the centromere and the portion of the chromosome is centromere The name of the organelle is called centrosome please don’t confuse between both of them Now Anaphase | centrosomes starts pulling the chromosomes via spindle fibres two lines will move to opposite directions Now the last step of first cycle
Telophase | during Telophase | chromosomes reaches the ends of the cell nuclear membrane forms again cell starts to split into two
this process of splitting is called cytokinesis now two cells has been formed each cell has 23 chromosomes but both of them 46 chromatids now both of these cells enter into Meiosis || during prophase || nuclear membrane disappears again There is no process like crossing over takes place here during metaphase || chromosomes lined in the middle chromosomes lined in a single line in the middle As like Meiosis |,centrosomes come to both the ends of the cells and the spindle fibres from the centrosomes will joined with centromere during Anaphase || centrosomes starts pulling the chromosomes here the chromatids has been splited At last Telophase chromosomes moved to the end nuclear membrane forms again cytokinesis takes place and the cell seperated into two cells so totally four identical cells Now each one of these four cells has 23 chromosomes and 23 chromatids So when we see an overview cell before entering into the meiosis has 46 chromosomes and 46 chromatids( 46 DNA strands) After the Meiosis four cells are produced each carry 23 chromosomes and 23 chromatids (23 DNA strands) Now lets try to answe the question which we discussed earlier How children born to the same parents differs each other The answer for that is Crossing over That takes place during Prophase | During crossing over As the segments in DNA is exchanged new DNA sequence may be formed So each person will looks different Also note that there is no crossing over takes place during Mitosis this is because In Mitosis the identical cells should be produced Please SUBSCRIBE For more educational content Thank you

31 thoughts on “MEIOSIS explained in Tamil | Reduction division

  1. சூப்பர் சகோ அருமையான பதிவு மிக்க மகிழ்ச்சி 👍👍👍👍👍👍👍👍🙏🙏🙏🙏🙏

  2. Brother tnpsc prepare pandren ..unga way of teaching and content semmaaa..nega yen full cell division concept video va poda kudathu yen na ungala romba clear ah explain panna mudiyum nu ninaigeran so please it's my request..please upload cell division fully…

  3. Vera level… Neenga niruthaadhinga… Tamil Nadu la rombbaa remote places la ellaam irukrava students Ku… Sila subjects Ku teachers eyy Vara maatanga! Avangala maathri irukravangalkum sari.. subjects onnumeyy puriyathavangalkum sari.. unga videos ellaam pakkaava puriyudhu.. language um rombbaa simple aah irukku… Cheers!! Very veryyy helpful!! We need more videos from you bro!!😊😊😊

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