AIIMS / NEET 2019 – XI Biology: Cell cycle and Cell division Lecture – 7 - Videos

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1. Review of Leptotene & zygotene
2. Pachytene
3. Crossing over
4. Diplotene
5. Chiasmata
6. Diakinesis
7. Terminalization

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44 COMMENTS

  1. Sir telomere chromosome me two arm long hoti hai and centromere centre me nahi Hota hai is liye repulsion more
    Hone ke Vajah se cross ing over more honga aur more chiasmeta produce honge

  2. Sir I think that telomere chromosomes have only one terminal end and one centromere so there is less repulsion compared to other chromosomes (metacentric,submetaceentric,acrocentric)
    If less repulsion more chances of crossing over so more chance of maximum no. Of chiasmata formation

  3. since at telocentric chromosomes centromeres are at the terminal position, each chromatid has no discontinuation for centromere… incase of other chromosome centromere is present in between position of the chromatid so discontinuation of chromatid occurs here, whereas in telocentric chromosome continuous chromatid present . For this reason there is more probability of crossing over in telocentric chromosome than others. Because incase of other chromosome due to presence of centromere in between position of chromatid the repulsion between centromeres inhibit more the crossing over whereas in telocentric chromosome this repulsion is minimum cause they are situated in terminal position..

  4. telomeric chromosome has more no of chiasmata formation bcz more the length more will be frequency of formation of chiasmata and teleomeric chromosome have centromere at end which create more chances of crossing over

  5. Sir jo crossing over wala diagram hai usme crossing over hone ke baad bhi pairing hai to kya pairing rehti hai crossing over ke baad bhi?? Aapne yeh bola ki crossing over jo hui hai wo dna ke dhage tutne ki wajah se hoti hai to crossing over ke baad pairing kese reh sakti hai??

  6. Sir.. Teloomeric chromosomes have max. Chiasmata frequency because
    ..
    It's having terminal centromere so repulsion is only on the terminals not in the middle and the rest whole part is totally exposed for Replication… So that's why…. Frequency increase….

    … May be 🤷🏻‍♂️ I guess 😅

  7. In the telomeric chromosome.
    Centromere present at the opposit pole to telomere.
    therefore there is maximum crossover due to large surface area interaction between the non sister chromatids.

  8. Sir ji kya crossing over pachytene me hi pora ho jata hai ya kuch diplotene me bhi hota hai(sir ji yadi diplotene me thread tot-te nahi hai to diplotene me uljhe hue dna threads alag alag kaise ho jate hai)

  9. In telocentric chromosome the length of each sister chromatid is more without any interruption as compare to other chromosomes hence the frequency of chiasmata formation is more.

  10. SIR I HAVE NO WORDS TO THANK U EVERYDAY…I M SOOO MUCH OVERWHELMED BY UR HARD WORK WHICH MAKES ME TO DO MY BEST..AN IDEAL PERSON FOR ME..BLESS OUR ALL COMMANDOS SO THAT ONE DAY WE CAN MAKE U PROUD..

  11. in telocentric chromosomes..the centromere is towards the terminal side, leaving a long arm on one side and a v. short arm towards the other side…as u said sir, more the length of chromosome more will be the freq of chiasmata formation……so if we take 4 chromosome of same length, telocentric one will hv more chiasmata compare to othr ones

  12. sir apne bataya ki diplotene phase me chromosome ka kuch part replicate karna rha jata h isliye pairing hoti h
    but ye kise sure hota h ki homologus chromosome ki hi pairing hogi ,non homologus chromosome ku nahi

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