Hmm . . . that'll be a big disappointment to the double-stranded RNA viruses and other organisms and cellular functions that depend on dsRNA ( which include stem-loop structures, which are-double helical ! ) . dsRNA tends to take on talk ) 02 : 30, 26 August 2012 ( UTC)
42.
A good simple physical model of DNA " works " in the sense that you can see why the molecule has a double helical shape, you can compare the major groove to the minor groove, you can see why A pairs with T and G with C, and you can see how an accidental pairing of A with G can create a bulge in the molecule.
43.
In their seminal 1953 paper, Watson and Crick suggested that van der Waals crowding by the 2 ` OH group of ribose would preclude RNA from adopting a double helical structure identical to the model they proposed-what we now know as B-form DNA . This provoked questions about the three-dimensional structure of RNA : could this molecule form some type of helical structure, and if so, how?
44.
In their seminal 1953 paper, Watson and Crick suggested that van der Waals crowding by the 2 ` OH group of ribose would preclude RNA from adopting a double helical structure identical to the model they proposed-what we now know as B-form DNA . This provoked questions about the three dimensional structure of RNA : could this molecule form some type of helical structure, and if so, how?
45.
A-DNA is thought to be one of three biologically active double helical structures along with B-DNA and Z-DNA . It is a right-handed double helix fairly similar to the more common B-DNA form, but with a shorter, more compact helical structure whose base pairs are not perpendicular to the helix-axis as in B-DNA . It was discovered by Rosalind Franklin, who also named the A and B forms.
