asmi
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A)Which one corresponds to 10 nm and 30 nm size.,which one is sensitive to nucleases and insensitive to nucleases .
1. euchromatin
2.heterochromatin
B) histone helps in packaging of nucleosome:
1.H2
2.H3
3.H1
4.H4
C) which one relaxes + supercoils and which one relaxes negative supercoils.
1. topoisomerase I
2. DNA gyrase
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| usmle prep
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H1 helps in packaging of nucleosomes.
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| kris2c
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:idea: Which one corresponds to 10 nm and 30 nm size, which one is sensitive to nucleases and insensitive to nucleases.
1. Euchromatin ---> 10nm  sensitive to "Nucleases"
2. Heterochromatin --> 30nm
:idea: Histone helps in packaging of Nucleosome:
1.H2 *
2.H3 *
3.H1 -----> this is for tightening nucleosomes together
4.H4 *
:idea: Which one relaxes (+) supercoils and which one
relaxes (-) supercoils.
1. topoisomerase I ---> relax (-) supercoils
2. DNA gyrase or topoisomerase II ---> relax (+) supercoils
uhm...
:-k
___________________
Kris2c
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| usmleasr
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i am not sure about super coils other two i agree with kris..H1 is linker DNA ..other 3 H2 H3 H4 form nucleo somes..
euchromatin is one expressed ..so has to be loosely bound...10nm fibers..
heterochromatin is condensed..30 nm fiber
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| asmi
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Thanks kris,
You are absolutely right :icon_salut:
Heterochromatin is insensitive to nucleases .
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| usmle prep
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what is + supercoil?
& what is - supercoil??
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