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Number of base pairs per turn in 'A DNA' is
Number of base pairs per turn in 'A DNA' is
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Solution
The correct option is A 11
The variation of energy with the twist of the base pairs about the helix axis shows the straight DNA which is free in solution and most stable with about 11 base pairs per turn.
A-DNA and Z-DNA differ significantly in their geometry and dimensions to B-DNA, although still form helical structures. The A form appears only in dehydrated samples of DNA, such as those used in crystallographic experiments, and possibly in hybrid pairings of DNA and RNA strands. Segments of DNA that cells have been methylated for regulatory purposes may adopt the Z geometry, in which the strands turn about the helical axis the opposite way to A-DNA and B-DNA. There is also evidence of protein-DNA complexes forming Z-DNA structures.
The variation of energy with the twist of the base pairs about the helix axis shows the straight DNA which is free in solution and most stable with about 11 base pairs per turn.
A-DNA and Z-DNA differ significantly in their geometry and dimensions to B-DNA, although still form helical structures. The A form appears only in dehydrated samples of DNA, such as those used in crystallographic experiments, and possibly in hybrid pairings of DNA and RNA strands. Segments of DNA that cells have been methylated for regulatory purposes may adopt the Z geometry, in which the strands turn about the helical axis the opposite way to A-DNA and B-DNA. There is also evidence of protein-DNA complexes forming Z-DNA structures.
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