| Re: How many base pairs in "twist" of double helix? I googled: DNA twist angstrom
Looks promising; here's an example: DNA Spiral
2. How many bases are included in each twist of the DNA molecule?
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The Watson and Crick structure of DNA sometimes called B-DNA...yes there
are different forms of DNA...the real story in biology is always more
complex...this is the most recognized form of DNA, partly because the
pattern it produces in images using x-rays resembles the DNA we find in
sperm. This being said, here are some of the dimensions of B-DNA
...
* Its diameter across the helix is about 20 angstroms
* It has ten base pairs for every complete twist of the double helix
* The helix has a rise of 34 angstroms for every complete 360 degrees of turn
* Since the helix is not the simplest twist that is often shown in secondary school books of cheap models, but what I think of as a helix upon a helix, the indentations of the helix are unequal and there is a deep or major groove and a shallow or minor groove. For a decent model go to: DNA structure
...hope this helps.
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