DNA Topology || Linking number || Twist || Writhe

[@ShivaniSingh-jp8qw]

She has covered Watson completely in her videos. Very well explained

[@wildpredator1616]

Wow. That's some unique information. Thanks a lot

[@animeshhb]

Can anyone please explain why writhe is less than zero in case of RH helix??? Because if writhe is less than 0 that means we are applying negative supercoiling to right handed helix which will in turn decrease the number of twist and Linking number. Again, applying writhe greater than 0 will cause the right handed helix to twist more in right handed side causing increase in number of twist and Linking number. I may be wrong. Please explain 🙏🏻

[@Kiwi.an_bean]

I think here the negative and positive sign when calculating only shows the direction of turning with respect to the original clock/aniti clock twisting of DNA. By definition negative supercoiling usually refers to when DNA is un winded whereas positive supercoiling is when DNA is condensed further. But here cause the linking number can't be changed and is kept constant we use -(negative) or +(positive) signs to maintain the ratio between twists(Tw) and writhe(Wr). ( As Lk = Tw+ Wr) So even if a strand of DNA which in RH in nature is being twisted clockwise it's supercoiling would still be positive as the number of twists (in equation) decreases and to maintain constant Lk we're required to add writhe (Wr) hence making it positive. This is what I understand,do provide info if I made a mistake.

[@Kiwi.an_bean]

Just like how DNA in humans is stored via coiling around histone proteins,it's by definition an ex of positive supercoiling and we can say that here the number of twists might be decreasing as it's writhe is increasing (coiling around histone proteins). So as per equation Wr would be + as twist might be decreasing in number but still decreasing of twists doesn't equal DNA not condensing as it is being coiled into smaller size. I.e, just cause number of twists are decreased doesn't mean condensing isn't happening.

[@srikantpanda7993]

good one

[@sabitasinku9548]

Mam great explanation 👍👍👍👍 support from Odisha

[@RethinkBiology]

This means a lot, thank you, please do share with friends.

[@PowerhouseCell]

Woah this is really cool! Love seeing the overlap between maths and biology :D It's great to see other biology KZbinrs!

[@RethinkBiology]

Thank you, this means a lot. 😊

[@PowerhouseCell]

@@RethinkBiology You're welcome! I've always wanted to make a DNA Topology video on my channel haha, yours was great!

[@radheyradhey5434]

Great

[@RethinkBiology]

Thanks a lot

[@aniketdas7803]

Really helpfull ❤️🙏

[@RethinkBiology]

Glad it was helpful!

[@bhavishapatel8459]

Very well explained ✌️ keep it up😋

[@RethinkBiology]

Thanks a lot 😊

[@tanu6464]

😍😍😍😍😍😍😍😍😍😍😍

[@suprioparbat2095]

Very Nice Explanation! 👍👏

[@shibanandasharma9558]

Thank you ❤

[@RethinkBiology]

You're welcome 😊

[@saykar0393]

Great!

[@Lwilight]

Well done

[@RethinkBiology]

Thanks a lot!

[@Lwilight]

@@RethinkBiology Absolutely, you guys are an excellent resource for students, keep it up!

[@RethinkBiology]

My pleasure! Please share..

[@iswamyyadav]

Good mam #highschoolbiology

[@RethinkBiology]

Thank you

[@iqraijaz58]

Beautifully explained. I have subscribed.

[@RethinkBiology]

Thank you for being with us 😊

[@saigonmonopoly1105]

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[@deblinamandal4555]

Amazing

[@RethinkBiology]

Thank you! Cheers!

[@auriffarooq2740]

Wrong info Write show amount of coiling. 5 + three writhes is 8. Now 8 time s we need to open both strands. Your example change lk to again 5 that is again definition of lk

[@saigonmonopoly1105]

that negative electomagetism loop

[@louisebrt243]

Trank you !!

[@설레임-w8w]

하이고 어렵다 ㅠ